Preamp Deal of the Century

Hi Slowhand. No.......without a rectifier, the preamp would not power up. No rectifier = no power. The rectifiers's duty is to convert the AC voltage[ 115-120 volts alternating current] from the wall plug to 6 volts DC [direct current] for operating the other tubes in the preamp. The regulator tubes[6L6,6f6 etc] are used to smooth the residual ripple in the dc voltage "after" the rectifier has converted the ac to dc. If you want to use the preamp with the 5y3 for rectification duty, there is a proceedure you can use to prevent or minimilize any cathode stripping of the other tubes. It's a bit of an inconvenience but it can be done. Power up the preamp for at least 5 minutes with the stock rectifier,this allows the other tubes to slowly turn on and stabalize in the circuit.Then turn off the preamp and quickly insert the 5y3 in place of the gz34 and turn it back on "immediately". "NOTE" Please understand that I am "not" recommending substitution of the stock rectifier with the 5y3 or any other directly heated rectifier for that matter! Warming the cathodes or heaters of the 6sn7's and the regulation tubes with the recommended rectifiers will minimilize the cathode stripping of those tubes. Cathode stripping is caused by the tubes being subjected to a blast of full voltage before they have had a chance to warm up and stabilize themselves in the circuit. Man...O... man.... Mick would surely be rolling his eyes if he reads this post!

Hello WcMustang, Congrats on your new acquisition. Tricked up? Can you elaborate. Did you order it with the px4 directly heated triode? I too am considering buying one myself. I have never heard the tube in a preamp stage however I have played with the a few px25 triodes over the years. These directly heated triodes, when used in an output stage of an amplifier have an incredible purity to them,amazing resolution of very fine micro detail and nuance that most output tubes only hint at. Hope you will post your thoughts after break in.... really looking forward to it!

Hi Fiddler. To employ the 7193 in the chardonnay one would have to drill a hole beside each tube socket to accommodate the wiring to the caps . Probably not so good if you ever wanted to sell it. I run my wiring up through the extra tube socket of my cortese as mine is configured for a pair of single triodes/channel as opposed to the single socket dual triode 6sn7 versions . Another way would be to run the extra wiring down from the bottom of the chassis and up the sides if you want to give it a try.The good thing here is the operating points of this family of single triodes [6j5,6c5,6p5,2c22,7193 etc] are the same as the 6sn7 whereby no modifications are necessary to the circuit of the 6sn7 based suprateks. Perhaps you might want to try a 6j5, 6c5, or the 6p5 first as they don't require the grid caps, the wiring change is relatively very simple and would certainly allow you a lot more flexibilty with your gain. The round plate versions of the 6j5 and 6p5 vacuum tubes as well as the 6c5 meshplates sound better than all of my 6sn7's. Trying a few of them first will certainly allow you to hear the voice of this tube family. As mentioned,the 7193 and the 2c22 need a pair of top caps per tube. These top caps a very difficult to source nowadays and it is imperative that they fit snuggly on the contacts of the tube. Not recommended for those with children or pets. You are more than welcome to email me off line for more imfo.

Hey Gang. Anyone else using the Grange with the px4? I am seriously considering ordering one but I am a little apprehensive as I would have to part with either my syrah or the cortese to raise the funds. Would be nice to hear a little feedback from a supratek user that has upgraded to the Grange. I have a welbourne labs attenuator on order for the Cortese but it's currently in a back order situation. Wouldn't make the move until I have installed it in the cortese but was hoping some users will post in the meantime. Thanks David

Hi Gang. Ongaku, thanks for the post. Sandro, congrats on your new supratek and I am sure you will enjoy the ride. EThifi, Have you spent much seat time with the preamp in the low gain setting? If it is loud at 9 oclock on the volume control, it leaves you with a very small window for adjusting the proper gain variations of many recordings...... WCmustang....While neither my syrah nor the cortese use the ecc88 in the phono stage, I do have an ARC sp-10 and the Klimo merlin in others systems. Both employ the ecc88/6dj8/69922 family of tubes and are very fine sounding high end preamps. I have also owned as well as repaired and modified many other preamps that have employed that family of tubes. There are some great ones, some good ones and a lot of mediocre tubes in that family. Many of the nos ecc88 family of tubes have a tendency to be somewhat microphonic and can also be noisey as well. The crop of currently manufactured tubes..... while most are quiet and void of microphonics,in my honest opinion; none are fit for use in any high resolution phono circuit and to my ears "just won't make music". The pre 1970's tubes from amperex, siemens,telefunken,mullard,valvo etc are light years better than post mid 70's and 80's examples,particulary the siemens made tubes. Further more:There are a ton of re-labelled examples floating around and have been for years.In my experience, the only modern tube of any consequence is the military version of the Soviet 6n23n or 6n23ev,infact... these are the quietest tubes in the family with the tightest triode sections as well.The post 1980 phillips ecg versions are hideous sounding. The 60's version white labell Holland made Amperex [d getter versions] are terrific as well as the US amperex versions. The pre-70's Siemens e88cc's were my favs in the Sp-10 and the klimo and preferred over the Telelies and the mullards. Both versions of the legendary CCA's from either siemens or telefunken are as good as it gets in this tube family however the late 70's examples are nowhere close sonically to the earlier examples. The early Valvos [pre 70's again] red labells are great as well. One may also use the e188cc's or 7308's as subs and all of them will handle a higher voltage and are geniune 10,000 hour tubes. JPMS, Thanks for your perspective on the px-4/300b supratek options. The dilema for me is, which one to sell if I decide to go with the Grange. I am leaning more toward selling the Syrah as my cortese is considerably better sounding and far more flexible in my system. I much preferr the sound of the nos round plate 6j5's over any of the 6sn7's. There are also many more single triode substitutes for the 6j5 .... like the many vintages of the 6p5's, 6c5's,6ad5's,6ae5's,and the fabulous 7193. Due to no real commercial demand for single triode octal tubes [yet anyway]all these tubes are dirt cheap, very plentiful, and many sound better than the dual triode 6sn7. To be candid here: My apprehension stems from having my doubts about whether the px4/300b version will outperform my cortese with the above mentioned nos tubes.

Hi Jazzdude. Thank you for your prompt response. I have little doubt the line of the Grange will best the cortese with the same single triodes in it for line gain. But is the cost of going that route really justifiable? If I do order one it will definately be wired to accomodate a pair of single triode octals per channel as opposed to the dual triode 6sn7.I can always rewire the sockets to accomodate the 6sn7's anyway.The delema here is: My main rig is voiced primarily for vinyl playback as I rarely listen to digital in that system, thus my apprehension in regards to going to the grange. I would have to sell either the cortese or the syrah to do so. I am leaning toward selling the syrah at this point as I will move the cortese into my second system to replace the syrah if finances permit. My cortese is just incredible with the 7193 in it!!! however the influence of the line gain is negligable at best when using the phono stage of the cortese anyway... thus my anxiety here.Anybody in the Golden Horseshoe of Ontario with the grange or cabernet?

PS: Jpms. You are a true gentleman sir! I sincerely appreciated your email today, thanks again. cheers David

Hi Edmund. The ASL 1009's are fabulous amps for the money.

Hi Steelhead. Yeah, Your very welcome sir and I'm glad your happy with it, a superb tonearm for mc cartridges. congrats on your chenin. cheers David

Hi Gang: Yes indeed, quiet 6sn7's are hard to find and all of that family of tubes tend to be somewhat prone to microphonics. Herbies tube dampeners are a blessing here as well as isolation. The Metal base GZ-34/5ar4 is without doubt the finest sounding of that family of rectifiers. When using substitute rectifiers like the 5v4,gz33,5z4,gz37,6106 etc,it is imperative that they test above 95% and both sides measure the same. The chugging sound some are experiencing here when playing vinyl is due to the excessive voltage drop of the rectifier type used. Insert a weak rectifier of any type and you may experience this artifact regardless of type, however the gz34/5ar4 will not exhibit this trait until it's much weaker than the others.Furthermore, ones choice of regulation tubes will not have any impact on this artifact. While a weaker rectifier may work in many other applications... they will be of marginal success in any of the supratek's that employ a phono stage. I have a nos Valvo gz-34 [test's just below 90%]that I use in a pair of vintage siemens klangfilm amps and they ehibit this trait in both the cortese and the syrah when using the phono stage. I also experience the same thing with a nos 5v4 and a Bendex 6106 and they both test above 90%. " Important Note"... all of the rectifiers that are employed in the supratek's are of the "indirectly heated" full wave variety, the 5y3gt mentioned else where is a "directly heated" rectifier type and not recommended. The use of directly heated rectifier types in the suprateks will eventually strip the cathodes of your other tubes. Not a good thing for those employing rare and expensive nos tubes. A directly heated rectifier will cause premature tube life with the other tubes as the getter of the tubes is used up quickly releasing gas in the tube.When cold,the gas molecules are struck by high energy electrons from the cathode, being positive they are attracted to the negative grid. The gas molecules will shoot right past the grid and onto the cathode,and therefore eventually eroding the cathode surface and compromises the life of the tubes. The other tubes employed in the preamp should not have instantanious voltage applied until they are warm, this allows the tubes getter to absorb the gas molecules that have accumulated from that last use of the preamp.

Sburke. Thanks for the imfo in the your last post. It sounds very much like a bendex 6106 whereby it takes a long time to energize.

Hi Gang. Simon, Yes, the Bendex 6106 takes about twice the time of any other indirect rectifiers to power up. It also requires a way more run in time than any of the others to sound it's best. Regarding the Gz37, I completely agree with Fiddler here 100%. It's just not the rectifier for the Supratek and he has described it's sound in the supratek to a T. Mind you... Your reference to a Phillips Mini-watt gz37, which I have never tried and wasn't even aware that Phillips made one. My experience was with the nos Gz-37 made by Mullard and I am not much of a fan. In my rig, the bendex is the winner in both the syrah and the cortese with the metal base gz34 a very close second.

Hi Sandro. You have another 200 to 300 hours of run in time before the supratek really finds it's stride. You must try the premium 7308's you are using in the ARC for the phono stage in supratek. It's an interesting comparison though with the ARC,I have a modded out ARC sp-10 mk2 that I still very much adore and will never sell it.It was my first true reference preamp that just simply trounced everything else back in the day. A wonderful voice to be sure, however my cortese betters it in every parameter and the line stage isn't really even close. The mod by Great Northern Sound certainly raised the bar for the ARC stuff,particularly in the bass response department[the achilles heel of the SP-10],but by contrast... the resolution and decay in the bottom end of the supratek is at a whole higher level. I have yet to hear any other tubed preamp compare in this area and still shake my head every day.

Bwhite. Amen!

Hi Gang. Doc... congrats on the new cortese... it truly is stupid good huh. I can only re-iterate to what mcmustang is alluding too, as the benefits are immediate upon first listen. Start with a good nos rectifier first.The early philips metal based GZ34 that mcmustang is using is about as good as it gets if you can locate one. They can be a little pricey but will also last longer than you or your equipment, pug it in and forget about it! Actually... Any of the vintage mullard gz34's are light years better than the stock rectifier thats supplied with your preamp and all of them are built like tanks and will last just about forever. For those with the 6922/6dj8/ecc88 tube family in the phono stage, there are many different flavours for voicing with but most of the 60's vintage tubes of that family will stomp on the stock tubes mick supplies as long as they are quiet and non-microphonic. I too,think the pre-70's siemens cca is the best of the family, although the white labell amperex e88cc's [d getter versions] present a musically compelling alternative. Line stage??? For those with suprateks employing the 6sn7 dual triode in the line stage.... many flavours here as well. I did try the eh6sn7 in my syrah and was pleasantly suprised, I found it to be very quiet and a tonally well balanced tube overall, but the tung-sol round and kenrad black are certainly in another league altogether....far more organic, with superior dynamic contrast,depth of stage,and the ability to resolve that fine micro detail and nuance that seems missing in action with the EH. Both the tung-sol round and the kenrad black possess a certain decay to percussive notes that's akin to a real instrument in the room. As usual... your mileage may vary. Enjoy!

Hey Doc. What cartridge are you using?

Hello gang. Fiddler... thanks for the heads up, as I doubt I put anymore than 20 hours of seat time with the EH6sn7's in the syrah.I will certainly run them in again as I do like their tonal balance. DOC... You mentioned a little hum at very high gain in the phono stage. Hum, as opposed to tube rush or tube noise is generally a grounding issue somewhere between the cartridge/arm and cable interface to the phono stage. A 60hz buzz that piggybacks the signal from your cartridge and sometimes can be a pain in the butt to get rid of.

Hi Gang. Mustang... Ahmen and well said! Lugnut... "you got mail".....Simon....If you can ascertain the vintages of the good singles you have I would most likely have a mate for any one of them. Feel free to email me. Just catching up on the thread here as I recently experienced a full scale computer crash, I am a certified knucklehead with these damned computers. AHHHHHH!. For those without a tube tester or do not have a trusted source for nos tubes.... the EH 6sn7 is a very synergistic tube for line gain in the supratek's and really a no brainer. I have been running in a pair in my Syrah [about 40+ hours] and am more than a little suprised at how good they really work in the curcuit, they sound considerably better after the 24 hour mark. Gotta go now.. cheers

Hey Slowhand. How about a progress report.

Hey Larry. January 04!!!! Are you kidding? Geez, I have been seriously considering ordering a new grange but don't think I could wait anywhere near 2 years to get it.

Hi Gang. I'm waiting on a custom stepped gain pot[vishay resistors]to install in the syrah even though I will lose the remote function, I will also install it in the cortese for comparison. If I order the grange, either the syrah or the cortese will have to go first.Though I am hoping the new pot will bring the sound of the syrah closer to the sound of the cortese.

Hi Gang. Slowhand, Congrats on the new toy. Yeah, the run in time is always a major pain in the butt for most any new equipment, particularly hardwired vacuum tubed stuff.Now that Mick is using the Mundorf capacitors in the suprateks will only prolong the exercise to be sure, not to mention all the transformer coupling employed in the circuit design. Any capacitor employed in the signal path of any given audio circuit will need a steady diet of a modulated frequency to fully open up. Oil filled types in particular are notorious for an excessively long burn time. The Jensen oils,Audionote oils and the Mundorf supreme caps all take at least several hundred hours to completely open up the window. The Mundorf supreme's midrange is magical, incredibly clear and concise right out of the box. With more run in time you will find that window opens larger and larger in both the vertical and horizontal plane.That incredible focus and resolution of the midband will slowly expand in both directions of frequency. The bass frequencies will take the longest to fully open up but when they do they are incredibly resolved.The speed,the pitch, the attack and the decay of bass instruments per sey, percussive bass in particular....cello, stand up bass,plucked bass etc are all just so well resolved it's incredible and almost to good to be true. Moving up in frequency from the midband....brand new the Mundorf's are already very extended,smooth and articulate. It's difficult to imagine and even harder to explain because it's not just so much as reproducing the notes here but the mundorf's ability to capture the sound of silence, the air and the atmasphere surrounding the notes.The space between two or more instruments playing together in the same frequency domain whereby one can clearly focus on each of the musicians instruments as well as ascertain the distance in perspective between them. The Mundorf supremes uncanny ability to clearly focus at both frequency extremes is in a class all by itself in my opinion. You guy's may want to try them in your speaker crossovers well. The Tannoy Westminsters use high quality film caps and resistors in their crossovers to begin with but I was completely floored at what the Mundorf supremes did for them.It's not so much a tonal balance thing here, but that subliminal space and timing thing I was alluding to earlier. The only down side here is that they take even longer to run in when used in a crossover! For those that are impatient or don't like to hear the ongoing change while running in capacitors, Get yourself a copy of the George Cardas frequency sweep LP and let it play for a day or two on each track of the record, your good to go in about 10 days. For those that don't use a phono stage... theres the denson cd, it's basically the same thing, just put it on repeat when your away from your rig, You don't need even need to turn your amp on for this exercise unless your using them in your speaker crossovers. Tom.... If you can't find a copy I can send you mine. cheers

Hey Steve. Thanks for the offer sir, as I may just take you up on that one, however I am sitting on the fence for the time being until I can get some seat time in with the stepped ladder potentiometer I have custom ordered for the cortese. Should be installed in another week.

Hi Larry.I guess it would be similiar to a flower-lover observing a rose bud as it opens up into a beautiful flower. Perhaps some people may find the ritual of capacitor run-in an enlightning or rewarding experience. Once is more than enough for me thank you very much, though it really is amazing to hear it morph out. The quickest way I know of, is to wire the capacitor in series with an 8 ohm resistor and then hook them across the speaker terminals of any old receiver/ amplifier.The 8 ohm resistor is basically a dummy load for the amplifier to see.Leave it on for 4 or 5 days dialed in to a radio station and your good to go. If you have a spare cd player you can simply run it in repeat mode with a selection of music containing an extended bandwidth. I use the Denson "frequency sweep cd" as it contains a full scale sweep that covers every octave. Warning!!!you certainly wouldn't want to listen to it though.

Hi Larry. Congrats on the supratek. Like any new gear,it will take a good 40 to 50 hours of run-in time to settle in and find it's voice.The suprateks sound great right out of the box but it's pretty neat to hear the metamorphosis.Most new tubes need a day or so to settle in anyway.A few of the gang here have rolled in the EML 45 meshies and will hopefully chime in.

Hi Tom. I am not at all surprised.Like the majority of oil filled capacitors, the mundorf supremes take a couple of hundred hours to fully open up. In particular, the bass frequencies takes the most time. If you want to speed up the process... run a cd on repeat when your not listening to your rig [just leave your amp turned off]

Hey Indigorose. Congrats on the new Supratek....and a GRANGE no less. Simon, there are many applicable alternative subs for the 6L6 in the regulator position. IMHO the tung sol 5881 as well as the rest of 6L6 family are grossly overpriced/performance due to the huge demand by the guitar guy's. The voltage rating for any version is a non issue in the supratek anyway and nothing to worry about. The early shoulder bottle types are typically the better sounding though. The nutty prices we see on the metal based gz34's are for a very good reason.... they really are that good in most high resolution amplification however, a good old mullard, amperex or Valvo are very close if tests strong and each section is closely matched.

Hey Larry. Your post is a class act, no apology needed IMO. Great to hear your supratek is starting to come around. It gets even better after a few hundred hours of run-in.

Hi Allen. The 5u4g will work for rectification duty but really not recommended in the supratek. It is a "directly heated" rectifier wherby the 5ar4/gz34 is an indirectly heated rectifier.... meaning it has a much slower ramp up time preventing any cathode stripping of the other tubes.

Hi Allen. Yeah, I can appreciate the beauty, however considering the cost of any nos 5au4, the sovtek looks a whole lot better in a box.

Hi Colin. When used for regulation duty [rather than used as an output tube] the 350b, 6f6g or any of the other tube choices should last longer than you will! That said: the rectifier will have a far greater influence on the sound of the amplifier regardless of ones choice of regulation tubes. Considering the cost of admission for a pair of strong testing 350b's, one would be miles ahead investing in the metal based version of the GZ-34. Yes, they are rather expensive....but far and away the best sounding full wave rectifier on the planet.

Hi John. Firstly, congrats on your new addition: amazing eh. Amandarae...a very good description regarding the duty of the rectifier and regulation. John, are you experiencing this image wander artifact with the phono stage only.... or is it noticeable with cd playback as well? The supratek preamps exhibit the most focused and stable imaging out there, and to this day the best yours truly has ever heard in that regard. I would hazard to guess this image wandering to be a tube related issue as opposed to speaker placement. The rectifier being the usual suspect here and the common denominator. It would be a good idea to test your rectifier,making sure it test's strong and matched on both sides.... a weak or an unbalanced rectifier will surely exhibit some image shift or wander. For example: the sovtek 5ar4's are notorius for image shift and wander in many high rez tube circuits. I wasn't aware that Mick is now supplying nos Mullard rectifiers as a stock tube with his preamps, kudos to Mick. The nos Mullard 5ar4/gz34 will traditionally last for many many years however, being that they are a full wave rectifier... I have seen more than a few with unbalanced halves. Further more: mismatched regultors can also exhibit this artifact.

Hello Houstonreef. Congrats on your new found supratek. The linestage tubes will be the first pair of the larger [octal based] tubes behind the smaller phono tubes. The original line stage tubes supplied with the Syrah were the Sovtek 6sn7's. What type of 6sn7 tube was the previous owner using? Most any other nos 6sn7 should be a major improvement over the Sovtek's. The newer suprateks are delivered with the Electro harmonics 6sn7, certainly far better sounding tube than the sovtek's however still not in the same league as some of the better nos 6sn7's. Your welcome to my pair of EH 6sn7's and/or the sovtek 6sn7's for the cost of the postage. Everyone have a very Merry Christmas and all the best in the New Year.

Hello Frankiealverti. Certainly, the nos sylvania 6F6gt will perform as well or better than any other 6f6 type for regulation duty in the Supratek's providing they test strong and are closely matched for gm. I am still using a pr of them in my Syrah. The regulator tubes can have an influence in the sound of the supratek's however, the difference's are rather subtle here.They are used in conjuction with the rectifier to smooth out the residual ripple of the rectifier in the power supply . Far greater rewards are gained by changing out the stock rectifier first for a strong testing nos gz34/5ar4 before even thinking about rolling out the regulator tubes. Without rolling out the stock rectifier first....changing the stock regulators for something else would just be an exercise. By the way: When I first recommended the 6F6g for regulation duty way way back near the beginning of this thread, it was more to inform people that the 6F6G [shoulder shaped glass types only] was a low cost alternative to the stock Sovtek 6L6/5881 that Mick was supplying at the time.Most Nos tubes in the 6L6 family are rather pricey to say the least and some in that family are hideously expensive [the genelex kt66, Western Electric 350's for example]. At the time, I was using a pair of Western Electric 350b's only because I had a few pairs laying around in my stash. I could not and would not recommend them in good conscience, the cost for a pair of them is far better invested in music or elsewhere in your rig. The high cost of nos 6L6 types are due to the demand by the Guitar amp crowd. There are a whole host of nos tubes that will work for regulation duty, many are less expensive to acquire than the new issue tubes in the 6L6 family.

Houstonreef. The Ge 6sn7gtb.... if it is the sidegetter version, it is the proverbial "over achiever" if there ever was one in the 6sn7 family. A great score for paltry sum these can be bought for and they fly way below the radar relative to the cost of the other nos tubes in the family. [for the time being anyway]and they sound very good in the Supratek's. Sonically speaking, they are very smooth with a well balanced tone from top to bottom, decent at resolving subtle detail and posses a very punchy bass line [one of the best of the nos 6sn7's in that regard] a robust and reliable tube that's generally free from microphony and low in noise.Certainly not as texturally layered and transparent sounding as the Kenrad blackglass or Tungsol roundplates but certainly not bad in that dep't either. [ then again, only a few others nos examples are] and they generally sell 5x the price. It has been mentioned in the thread that Mick has voiced his current preamps with the stock EH6sn7 and it is a large improvement over the sovtek 6sn7. I would certainly agree with the general concensus when compared with the sovtek however, I do not concur with the general consecus here when compared to many nos 6sn7/vt-231/5692 varieties. The GE 6sn7 sidegetter easily best it, the reasonably priced RCA grey glass versions literally stomp all over the stock EH 6sn7 in every dept. Move further up the family food chain.... to the Kenrad Black or the tungsol roundplate....well.... a whole nother stratosphere to experience. Comparing the two would be like comparing the Supratek Chenin to an old Conrad Johnson preamp employing tired tubes. The 6GK5's in the pro/comm box are probably a late production tube rebadged with their label. Most of the 6gk5's out there are late production tubes and probably all made at the same facility anyway and then rebadged with a Mullard logo or number of other company's name. The early nos examples all had factory date codes. I have a pair of old stock Amperex's with factory codes and bugle boy labels that are far better sounding than the later production examples without the codes. The US made RCA 6gk5's are the way to go here if you can't find the older tubes as they are generally low in noise and all sound consistent.I suppose it's a moot point here for those with the latest production Supratek preamps that are sporting the Covi designed phono stage however those with older Syrah's and cortese models that employ Micks version of the renowned Loesch design should go out of your way to dig up some old stock 6fq5's in place of the 6gk5....A major impact and a big surprise to be had here folks! Regarding the 6bg6???????? Houstonreef, are you positive they say that somewhere on the tube! I am surprised, no more than surprised they would even work in the Syrah, unless the previous owner had the tube socket rewired to accomodate a 6bg6. The 6bg6 is electrically very close to a 6L6 however,it is traditionally employed as an output tube in an ampifier but requires a top hat on the top of the tube to operate in any given circuit. Just "Mind Boggling" to me as to why anyone would go to the trouble of using that tube for regulation duty in the Syrah anyway.

Frankiealverti. Houston...We have a problem!!!! Are you certain the tubes are 7029's. I have never heard of a 7029 designation. Perhaps you are confusing it with the 7027 or the 7027a. If it is a 7027.... Yup, the 7027 is electrically similiar to a 6L6 and should be fine in the supratek. That said: Am I missing something here? No offence but I would be "highly suspect" and immediately ask myself why anyone one would go through the exercise of relabelling tubes,and for what reason other than financial gain. Flat out Fraudulant if you ask me! The original old stock 7027 is a rare breed indeed and I have only come across this tube once or twice in over 30 years. A local musician brought in an old Ampeg guitar amp that employed the 7027 tube. I could not find replacements for them and had to retrofit his amp to operate with the 6L6's. Rumour has it, that the 7027 is the King of Tone and the cats meow in the this old Ampeg. The gentleman I am referring to is an incrediblly talented blues player and quite a famous recording artist. His comments were....What the f_ck did you do to my amp man! Well sir... " I put some [old stock] 6L6g's in it man as I couldn't find the 7027's anywhere" I could only imagine that the guitar amp crowd would probably trade in their back up guitar for a pair of these! Frank...I don't doubt the original old 7027 sounded better in the Heathkit W5's but I would be willing to wager that they are probably new stock chinese or russian metal base 6L6's with the labels washed off. Why take the chance in your Supratek anyway? Regarding the preamp making noises when your using the phono stage. Have you tested the rectifier? I would hazard to guess that your Mullard GZ-37 is either very weak or has grossly imbalanced halfs.This artifact you describe is really not that uncommon particularly in the supratek with phono stages. Yes, I believe the GZ34/5ar4 would be the safer choice. By the way: WOWZA and well done man!... You have one fabulous rig there sir and a very fine ear. To this very day I am still kicking myself for selling off my Radford ST-25. Over the years....I have had my share of highly regarded amplifiers paired with the Quad 57's and I can honestly say I have never heard a better amplifier than the STA-25/quad combo. Outfitted with the Genelex kt77 is pure magic with a capitol M. Now add the mighty supratek into the mix....sigh. Can only imagine!!!!

Hi Houstonreef. OK,things are a little more clear now. As I mentioned in my last post the 6bg6 is an electrical equivalent to a 6L6 however it requires a top hat connection to the contact on top of the tube to power it up. Could very well be a factory version from Supratek for all I know. I would suggest you email Supratek and ask Mick if he made it that way or perhaps you could ask the previous owner if he rewired the socket to accomodate the 6BG6 tube. To be candid here: Unless you are into tube rolling of the regulator tubes it nothing to be concerned with anyway. RE: Power up procedure [important]. When the JC-1 is in "standby mode" there is no voltage or power at it's output whereby you can leave it powered up 24/7 if you wish.It is very important to be sure the preamp is powered up and running PRIOR to switching the amplifier from standby and into PLAY MODE . Powering up the preamp when the amplifier is in play mode can potentially damage your speakers, amplifier or both. When shutting your system down.....It is imperative to turn off the amplifier first before the preamp. In your case, switch the amplifier out of play mode and back to standby mode before powering down the preamp. You can leave the JC-1 in standby mode 24/7 if you wish.

Hi Frankiealverti. Hmmmmmm.... If the symptom is common to both rectifiers I would think the problem is elsewhere in the preamp. The phono stage tubes in the Syrah are battery biased,perhaps the batteries need to be replaced and hopefully they may very well be the cause.

Hi Frank. Yup, change it out and let us know the result. Cheers david

Hi Houstonreef. Sounds like your having a bit of a time with your syrah. Is it it a 60 cycle hum or is it a buzz that seems to piggy back the signal? Do you get it on the phono stage as well?

Hi Simon. The Mullard GZ-37 works well in the Syrah and should sound better than the stock sovtek.

Hi Simon. Your Mazda labelled Mullard gz34 would be the one to keep as it not only sounds better but will last for many years to come. In my experience.... the gz37 will need to test near 100% and be tightly matched on both sides to get the best performance from it....It is only marginal if not. Yup...the sylvania 6L6ga black glass is a very good sounding tube and much sought after by the guitar amp crowd. I think most of old stock 6L6 tubes sound considerably better than the tungsol 5881 however few are as robust.

Hey Stiltskin. Great post. And you have to love the return on your investment on the tung-sol rounds.

Wow! I have not been following this thread that closely as of late but I think it would be a whole lot more constructive to address this glare issue collectively rather than questioning ones sensory acruity or posting antagonistic and/or ambiguous retoric. Hey gang, glare can manifest itself in too many ways and can be often be rather difficult to exorcize. System synergy and resonance control are of paramount importance here, paricularly in a system capable of such high resolution. Consider how many variables involved here.....room size,room dimensions,sound pressure levels,room gain,component compatabilty,speaker type, speaker efficiency, nominal impedance and crossover type,speaker Q, amplifier topology and speaker interface, tubes,wire, component support and resonance control etc,etc, etc. A complex equasion and invariably takes some effort[and money] to bring out the best in ones rig. Opus and Maril: Would you be kind enough to post your system here? A little insight as to your past experience re: equipment and speaker type, music genre,room etc. Perhaps we can get to the bottom of this. Cheers!

Hi gang. Just checking in on the thread and have not had the time to post my thoughts here in regards to the glare issues Opus and Maril are experiencing. Hopefully,I will find some time over the weekend. Jtgofish....BTW, all of the supratek preamps are wired with pure silver wire. However, your wiews on the use of silver wire for both speaker cabling and interconnects do mirror mine. Later....

Hi Paul. I use a cortese with the Tannoy Westminsters [98db] Dead quiet!

Hi Opus. I'm sorry I couldn't respond a little earlier and thank you for posting your system as it puts a lot of things into perpective here. A very fine system sir,I am quite familiar with most of your gear and it's nice to see another vinyl guy.... as vinyl has always been my preferred medium for "voicing" my own gear. I sure can appreciate your frustration with this glare dilema, it's got to be driving you crazy by now. However, please don't shoot the messenger here....stay the course and you will discover the supratek is not the culprit. If your nos tubes in the preamp test strong,are void of microphonics and low in noise than lets look elsewhere in your set-up. BTW, are the Kenrad's the blackglass vt-231's or the clear glass 6sn7's with the parrallel black plates? [huge difference between the two]. As Stiltskin alluded to earlier, system synergy is of paramount importance here particularly with a high gain,high resulution preamp coupled to amplifiers of the same pedigree. Personally speaking....I can only offer my own experience with the use of Silver cabling but: I have had "Zero" luck with any pure silver wire in any of my rigs. An interesting story....about 10 years ago I remember hearing some top of the line Siltech interconnect and speaker wire in a friends system which consisted of: an ARC sp-8 mk2,[originally mine] a conrad johnson mv-55 outfitted and adjusted with nos tesla el34's,driving a pair of Vandersteen 2ce speakers,VPI table with rega arm, grado sonata.A very musical system and I thought... WOW,this is consideraby better than the Cardas stuff he was using prior.I was quite impressed with this so I went out and purchased the same cabling as I was using Cardas cross at the time in all 3 rigs. To be candid here and make a long story short,it was the a sonic disaster in my room[s] regardless of associated gear. I must say that I did like it's vibrant bass/ midbass quality however it was rather lean in the midrange and seemed to add a specific sheen to the presence range. Female vocals,cymbals,strings and horns seemed threadbare without body or foundation. At first I thought this was a burn in issue and the tandem needed more run in time.I was using it with a pair of proac response 3's, Arc SP-10 mk and a ARC d-79b amplifier,none of which could ever be accused of sounding bright. I then tried it in my main system rig: a huge dedicated room [ approximately 36ft x 32 ft with 16 ft ceilings]with 4 dedicated ac circuits, acoustat 2+2's,MFA Luminescence pre, Melco reference table outfitted with the venerable "the arm" by Sumiko, a Koetsu rosewood and all cardas golden cross cabling. With the Siltech in the chain... the system was unbearably bright. The presence range was very zippy sounding,bordering on edgy and was decidedly more forward in presentation within the soundfield.Hey, the SP-10's phono stage is as good as it gets at rendering a sense of depth in a good live recording... Yup, the Siltech could be considered clear and transparent and I could imagine it could be the cats meow in some rigs. To be blunt and honest here...It just drove me to distraction. Fast forward a few years...... I had acquired a pair of huge Tannoy Westminsters from a local recording studio studio for placement in this huge room and was consulting with a few other horny Tannerds with regards to updating the crossover, rewiring and voicing these humungous horn loaded transducers.The late Harvey "the Gizmo" Rosenburg had spent countless hours voicing his highly modded pr of Westminsters and was using Goertz silver wire with an active crossover and dedicated tubed amps. I was very apprehensive [to say the least]of employing any Silver cabling after my ordeal with the Siltech however, I consulted with Harvey regarding my silver wire apprehension and after many phone conversations he finally convinced me to give the Goertz a try. Well.....to make another long story short... Glare galor! Out came the silver and in went the Cardas Golden Reference, hard wired from the speaker to the outboard crossovers and back to the amps. OPUS...Just an thought here. Do you know the approximate crossover frequency on your custom hybrid speakers? I can only surmize it would be in or near the presence area or the upper presence area [2k to 3khz]. Can you bi-wire them? Silver isn't the best choice with most ribbon type tweets that I have played with, particularly when crossed under 5khz. If you can bi-wire...just for fun try some cheap copper lamp cord on the ribbon only. This should give you some kind of idea as to the signature of the silver. Regarless, I just have to say the supratek family of preamps are without doubt a true reference quality source component. I love both my syrah and cortese and can't even fathom using anything else. All the best in your endevour. Cheers.

Hi Gang. I haven't checked in here in ages.... Current Supratek preamps are using the Auricap at the output. Fiddlers post on the V-cap teflon is right on the money. Teflon capacitors in general are considerably better at signal coupling than most other capacitor types when employed in any high resolution audio electronics. The V-cap teflon is a quantum leap above the rest. Any teflon film cap [regardless of manufacturer]should yield a substantial improvement over the Auricap.All capacitors do require some run in time to fully open up...BUT keep in mind that teflon based film caps do take many more hours of run-in time to open up to full bandwidth at the frequency extremes. That said: even when brand new, one can hear the superiority of a teflon cap with regards to signal purity, resolution,focus and tonal balance right from the get go. I have been using the V-cap in my Cortese,and as couplers in my amplifiers for a couple of years now and to be candid here....I just couldn't go back to the other film types regardless construction. The hype and all the superlatives given the Vcap are fully justified here. They must be heard to be believed! Hell...I was so taken aback with Telon capacitors I even use a Vcap for a bi-pass cap in conjuction with a mundorf silver supreme in the tweeter section of my beloved Tannoy Westminsters. Run-in or burn-in time: For those that want to swap out the Auricap for another cap? Some of you may want to hear this transformation occur [rather intriguing really] For those that don't have the patience or already know the score....When your not listening to your system, simply run a signal via a tuner or a cd player [in repeat mode] for a couple of weeks with the preamp turned on, there is no need to have your amplifier turned on unless you want to listen to it of course.

Hey Fla. Congrats on the new Cab dual. I would be very interested to hear your thoughts regarding the new dual cab as I am seriously considering ordering one to replace my Cortese. The whole concept is just brilliant, particularly for those that are bi-amplifying. Cheers.

Hey Fla. Did you get Dual cab up and running yet?