The 6.8uf VSF was on the tweeter(Vifa XT19).
All caps are broken in, they're from other speakers with hundreds of hours on them. |
How is the VSF that you tested used in the xover(e.g. tweet, mid, woof)? Which tested caps, if any, were not broken in? |
Would I notice a difference between an aluminum and copper VSF on my mid? |
Tonight a friend and I swapped out Solen, Clarity MR's, Mundorf S/O, and Duelund copper VSF's in a pair of custom speakers I designed and built.
Other than the MR's being slightly quieter and slightly more dynamic, the Duelunds put the rest to shame. The VSF's sounded more natural and had a sound stage twice the size of the rest. For the soundstage alone, I would take the VSF's. But their tonality/timbre really put the icing on the cake.
Now my only problem is...can I resist the CAST? |
I am using the Mundorf Silver oil for the tweeter and the excellent Jantzen Superior caps for the mids with Jantzen Copper foil inductors and the Best resistor made for loudspeakers the Duelund with excellent results .The Jantzen Superior caps are a great caps and one of the best buys out there. I have used many brands in amps.preamps and loudspeaker crosovers.I have 5 years and have used
Auricaps ,Clarity,Hovland The Duelund are the best if money is no object. |
And yes, I consider the quality of coupling caps quite important. |
I don't disagree at all, Steen aimed to take the best of the vintage technology and utilise it better.
Prior to his own designs, he used vintage designs such as paper in oils, and wax/paper types. |
Frederik one comment I made a few months ago was that the bigger the cap the bigger the dynamics. Even a bigger plastic cap had better dynamics than the small one. I took a lot of heat for that comment.
Comments were very common that "the size of the cap has nothing to do with anything". Some said it complete lunacy. Steen said "Go for older types following the simple rule that bigger is better".
You can correct me or disagree as I have no problem with that.
I kind of thought you would have thought the vintage foil in oil for the midrange being the second best to your caps (Duelund) by a long shot a crazy statement?
I found wayyyyy more difference in a Duelund CAST and VSF in the tweeter than a VSF and vintage foil in oil in the midrange.
Are coupling caps as important as passive crossover caps?
I do not know if you know of Arthur Salvatore but he ranks the Klipschorns as the greatest of vintage speakers and were class C (upper) used to be Class B. I have emailed him knowing he is a Klipschorn fan (and he is formerly from Toronto just over an hour from me) saying he has got to hear these speakers when up hear. If stock they were Class C (in a tough list) these are of NO comparison. I have owned them for 28 years and can say they ain't your Dad's Klipschorns!
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I can sense, there's little chance we're going to disagree on your findings. :) |
Frederik in my test which of course is only my one set of speakers. I could mix and match vintage foil in oil in one speaker and Duelund in the other and listen to both speakers. As soon as one speaker had plastic caps and one with the vintage foil I could listen to only one or the other speaker at a time. It was almost like they were out of phase.
Also when a plastic cap was put in for the midrange and Duelund for the tweeter and the signal goes through midrange cap. The Duelund did not give the same improvement. (yet the Duelund did when used with the vintage foil midrange cap)
By far the second best cap was the original foil cap in the midrange. Again no plastic. Many Klipsch fans say the AA crossover is the best I often wonder if it the foil caps they used then. Newer Klipsch crossovers used plastic (industry norm) and do not have the following.
I have yet to hear a customer of yours not think your caps make a natural sound.
My modern SS amp did not make the same improvement using Duelund as the vintage tube amp does either. My amp of course was loaded with plastic caps.
There is also a large following of vintage guitar amps, (my tech guy who plays guitar would have nothing but vintage tube guitar amp) vintage stereo amps all with no plastic as a common thread. The thing both vintage guys will talk about is the tone!
I do want to thank you as I have yet to find a downside to you caps.
My gut says and I am going to find out if your caps do the trick in a vintage amp. My gut says a vintage tube amp with (no plastic anywhere almost) and a set of Duelund coupling caps will blow me away. All the "real feel" of the vintage/foil with a massive noise reduction to really let you hear what is going on. To me your caps are the best of both worlds. |
As you correctly state, Steen was of the conviction that plastic was a malaise when it came to sound reproduction. He considered all statically chargeable materials imperfect in that regard. Stated popularly he meant only natural materials would create a natural sound.
His theories are certainly the reason why we use no plastic in our products. Be advised that his findings are based on listening tests, I cannot claim irrefutable evidence. |
Dgarretson I would agree totally on the vintage PIO caps.
I did like the vintage foil in oil in the midrange 2nd favorite to the Duelund but in the tweeters vintage was just garbage. So much slurring and noise just trash. I think/hope you will be surprised by the Duelund when you do get them. It is the realism.
I wish Frederik would clarify if the realism is the no plastic?
Frederik you mentioned quality of the whole chain. In that "quality" does that mean getting rid of plastic? Steen felt that very important.
I am just asking this as I do not know whether to fix up the paper bobbin OPT vintage amp or do a more modern one.
I have heard very expensive modern tube amps and yes they were smooth but not real sounding.
Fas948 has had the reaction I would hope for from Duelund coupling caps. I find Duelund does not show full glory if mixed with plastic caps. Is non plastic OPT the same?
Maybe Frederik could answer that when running a (plastic mid range cap) into the Duelund tweeter cap I did not get the full Duelund sound. I did with the vintage foil in oil cap the Duelund sounded great in the tweeter. What I mean by this is that one plastic cap in the chain was not good. |
Dgarretson
You will have even more shocking results using the Clarity MR on your woofers than the tweeters :-)
Thats where the clarity really excells, best bass I have heard from any system, WAY more impact than any mundorfs have in Low frequency response as you state above. However they MR ain't cheap in some of the values needed for a woofer, but well worth it if you don't want to screw around. By the way the only other Cap that holds up nearly as well in Low frequency impact is the Jantzen superior, all the other clarity caps, mundorfs, hovlands etc... Are dry and aenimic in comparison to the rich perfect bass the Clarity MR and Jantzen can produce, but all around the clarity mr for full range frequencies are a more refined cap. |
I also use Duelund R and concur with Face. Duelund R sounds both cleaner and smoother in my Merlins than stock Caddock MP power resistors. At some point I will try Duelund C-- but not until I've attended to other mods to components that I believe have better price/performance ratio. Meanwhile, ClarityCap MR in Merlin tweeter is VERY good, and I will shortly be trying MR in Merlin woofer.
Volleyguy, I won't bother to compare the PIOs to each other, but only point out how tricky comparing caps can be, even to "well-educated" ears. Before I wired in the A/B switch to allow instant comparisons, I simply replaced the Mundorf Silver/Gold dry caps that I was accustomed to, with various PIO caps in sequence. In nearly every case I was inclined to say Wow! how impressive a change. But what was really happening is that my judgment was being carried off by the emotional content of the presence region. After installing the A/B switch, I was able to evaluate each cap carefully, and in the end came back to Mundorf. Once and awhile I need to switch in a PIO-- say to hear the last measure of stoic weathering in Johnny Cash's voice on Solitary Man. But there is fine detail that just goes missing with these PIOs, and a slurring of LF that becomes monotonous. |
Duelund resistors to help out here.... Bigger soundstage, better dynamics.
Mundorf Resistors for half the price of the MILLS at about 1 to 2 dollars each are slightly better... The mills seem to narrow the sound a bit, and are not as clean.
Yes the duelund resistors in series with a tweeter followed by a duelund cap are the best, very natural and wide open sound. I have tried several of above combos, and actually from the get go seemed that duelund resistors got a little of a "BRight" wrap due to being silver, but they are more smooth and transparent than all the other resistors, but they should be at like 15 times the cost. |
I'm currently using Duelund resistors. They remind me of mox type resistors without the glare. Very clean and transparent unlike Mills. |
Dgarretson with all the caps you tried, you have not tried Duelund correct? The resistors yes? Curious if not, why not?
There are a set of used/brand new never used ones for sale here on the site now. They are VSF .33uf if anyone is interested. (100v crossover caps) |
Wow Dave on the fly! Care to rate the PIO ones? |
The clarity MR's will be as smooth and blow away any mundorfs over time... Probably around 500 hours or so.. Mainly the Mundorfs are great for midrange and hi's on speaker crossovers, but if your using in amps or other electronic full range signal coupling applications the Clarity MR caps are the best period. Not even the other clarity caps come close, totally different caps and sound. |
Your observation is consistent with the difference I've noticed between good dry-construction caps as compared to oil caps. I have switches on several source & line-stage components that allow on-the-fly comparisons between both types(Mundorf Silver/Gold(non-oil version), vintage Sprague Vitamin Q PIO, vintage LeClanche PIO, Jensen PIO, vintage Russian K40Y9 PIO). Most oil caps sound smooth & seductive at first listening, but in the final analysis tend to obscure detail and sound tubbie & sluggish. They do have their strengths--particularly in the presence region. |
Since I'm still awaiting delivery of my Duelund caps from a friend, I decided to to compare the Mundorf S/O's and Claritycap MR's that I have on hand in the time being.
I found the MR's sounded sharper, more accurate, more dynamic, and had better separation than the S/O's. The S/O's were smoother, but at the expense of everything else mentioned here. |
Sorry my speakers have a series tweeter inductor. .245mh. How does this affect sound quality? |
Dave I did not replace the series resistor is the crossover yet. Can you explain why series resistors make so much difference? Noise? Or Frederik that would be great for me to understand this. |
"Frederik was the CAST developed for Burt's horn systems?"
He was certainly the guy, who prompted us to go beyond the VSF. I wouldnt say the caps were developed specifically for his speakers though. They do seem to be a good fit.
"Is that why I noticed so much noise difference from VSF to CAST is the exagerration of noise caused by horns?"
Well, I dont use horns myself, and notice quite a difference as well. I believe its more a question of well designed speakers, than the choice of, ported, sealed, horns etc.
"This may be a touchy subject you may not want to answer and I understand, but the cost of CAST? Can they ever be mass produced? or VSF? Is it a volume issue or a manufacturing process issue? I remember reading Steen saying when the VSF came out that they only could be hand made."
They are certainly not mass produceable at the moment. I would say a mass production would only be possible if we were to develop our own kind of machinery, which is not currently feasible. Certainly, I would like to be able to do so in the future. However, this area of business is not typically something that creates large investment ability.
"Another question that has intriqued me is the noise reduction from VSF to CAST? Why? I for one did not expect it. Both modern caps and I understood noise reduction from vintage to modern but from top notch modern (VSF) to CAST I was not ready for. Is it the hardening process? Also have you reached the limits with CAST or is there still that same kind of noise reduction still possible?"
The CAST is special in the sense that we can harden it after the vacuum impregnation, something not feasible with the VSF. I hope in the future we will be able to take it further than the CAST. The CAST 630v cap is already using a more elaborate system than the regular CAST. We are researching different metal foils, paper types and CAST materials, those are other venues that may or may not yield improvements down the line.
"Could I expect the same kind of noise reduction on coupling caps in vintage tube amp to VSF or CAST that there is in the passive? or not the same magnitude?"
An impossible question for me to answer in good conscience. For one thing, I havent heard the improvement you got. Secondly, I have no experience with your electronics. I use CAST myself in my electronics, and do not want to do otherwise, but if its worthwhile for you?
"Thanks again."
A pleasure. |
Frederik was the CAST developed for Burt's horn systems?
Is that why I noticed so much noise difference from VSF to CAST is the exagerration of noise caused by horns?
This may be a touchy subject you may not want to answer and I understand, but the cost of CAST? Can they ever be mass produced? or VSF? Is it a volume issue or a manufacturing process issue? I remember reading Steen saying when the VSF came out that they only could be hand made.
Another question that has intriqued me is the noise reduction from VSF to CAST? Why? I for one did not expect it. Both modern caps and I understood noise reduction from vintage to modern but from top notch modern (VSF) to CAST I was not ready for. Is it the hardening process? Also have you reached the limits with CAST or is there still that same kind of noise reduction still possible?
Could I expect the same kind of noise reduction on coupling caps in vintage tube amp to VSF or CAST that there is in the passive? or not the same magnitude?
Thanks again. |
Thanks,
I aim to keep my participations in fora low on publicity stunts, doesn't help you nor me...
Regarding, what is the most important part. I find that to be quite difficult to answer. In my years in audio I've come to the conclusion that quality matters. I know that sounds easy but instead of saying a CD-player is 20%, an amp 30% and speakers 70% ( I know the total gets too big ), I've found that if either component or link in the chain fails in some way or another it's going to be very detrimental to your sound quality, beyond what some simple % values may or may not suggest.
Whereas our components in place of others create a small, large, vast difference is again a difficult question to answer. Personally, it probably will not surprise you that I'm in the same camp as Volleyguy, Stormen and Fas948. However, the "art" of making a system is of course a matter of getting the foundation where you want it to be first and then go from there. For further elaboration some of Steen's articles are quite good, as you can see he spends quite a lot of effort talking about mathematical filter functions, cabinets, drivers, phase etc. His work with components started when he was done with all the other parts (done to his satisfaction, that is).
To clarify, I run what could be called a full Duelund CAST system, with CAST components in all parts of the chain. Do I believe this improves the sound more than other brands of caps, inductors and resistors, certainly. Do I also believe that the used chips, topology, cabinets, drivers etc. etc. may play just as big a role, certainly.
Att: Volleyguy: Thank you for the compliment, most people do not realise how much you value positive feedback as a small manufacturer. But even if a guy only buys 2 resistors from us, and subsuquently reports back he really likes them, it makes my day!
Best regards,
Frederik Carøe |
Sorry of course that should say "your" not "you" opinions. |
I want to thank you Frederik for your wonderful sounding caps.
With the desire to get the most out of these caps I also would love to hear you opinions on what else in the chain does matter?
Thanks |
A well-considered & diplomatic response from the manufacturer with a refreshing lack of hyperbole. |
Thanks,
While I certainly appreciate the kind words about our products, I wanted to comment slightly on the comment Steen made about the relevant value of the cross over. What he meant at the time was that the cross over as a whole needs to be in order both with the filter function it provides and with regards to parts quality. Parts quality in itself doesn't do it, though as you can no doubt imagine I do consider it an overlooked part of the chain. Furthermore, I'm in accordance with the views put forward that a lot of other factors in the chain play a great deal of importance, it's one of the things that makes this such a fun hobby. |
Duelund_coherent_audio,
Let us have it please! |
Hi,
Been following this thread with increasing interest, as you may well imagine. For the record is my participation welcome, or would you rather I keep away?
Best regards,
Frederik Carøe
Duelund Coherent Audio |
Volleyguy, I don't dispute the significance of quality crossover parts, and am myself using Duelund resistors in conjunction with Claritycap MR. (I'm looking forward to reading the results of Face's cap shootout.) But to put the value of Duelund capacitors in perspective, it might be useful for you to explore a systems approach by say, switching to updated tweeters in your speakers, or trying better internal wiring. Where selection of piece parts is concerned in electronics, I've become much more interested lately in very low-noise resistors such as TX2575. This technology was simply unavailable in vintage era. While one may argue that Fischer engineers understood the lost art of "voicing" equipment around available piece parts, I kid you not that the sound & transparency of resistors priced $.10-$10 is all over the map-- and just as significant to the sonic outcome as a $500 coupling cap, particularly in terms of revealing inner detail. And generally there are more Rs than Cs in the signal path to make a difference. Dwelling on the role of one coupling capacitor in the system begins to sound like an 85 year-old cardiac patient who believes his entire circulatory system has been cleaned up because he had a heart bypass. |
Dave I take it by what say on system approach you are still not convinced that the crossover is (and according to Steen always will be) the weakest link in the system. You are not convinced 50% of your speaker $ and 25% of system $ should be in the passive crossovers.
I am not argueing just curious as even I admit until I heard the difference from VSF (which was the then king of caps) to CAST no one could have convinced me all the noise that was still left with even VSF.
After hearing the difference I am a Steen believer that there was/maybe still is MASSIVE gains to be made in the passive crossover caps in noise reduction.
After what I am hearing about the CAST in electronics as soon as I can figure out which tube amp to use that is an area I am going to be going. I can not even imagine how they will sound compared to worn out vintage foil caps? I expect massive noise reduction.
I have a gut feeling from what I have read from Steen (no plastic in the chain) a vintage amp with vintage tubes because of the no plastic in the output trannies and point to point wiring and CAST coupling caps for the super natural quiet sound. What do you guys think crazy? Still sticking to foil like the original in the amp but I am sure the CAST are MILES, and MILES quieter. I do see they make 400v VSF's now. A more affordable option |
Felix, Always good to hear from someone who knows how good a modded SCD-1 can be. I have not heard the drop-in analog modules such as VSE, ModWright, etc., but rather have developed my own approach in combination with ideas from Ref Audio Mods, Allen Wright, and Zanden. After many iterations beyond initial step of component-for-component piece-part substitutions, I am happy with a transformer-coupled analog stage with just two TX2575 resistors in signal path(which replace two inferior stock Sony SMD resistors that none of the other modders touch), one battery-powered monolithic buffer, and no coupling caps, discrete op amps, or other active or passive components in signal path. In the stock analog circuit there are dozens of devices in signal path that color sound in addition to the coupling caps. Moreover, the analog stage accounts for less than one-third of the net improvement of mods performed throughout the player.
IMO, the problem with this Duelund thread is that even if Duelund makes the best caps in the galaxy, in most applications, taking a systems approach that deals with other weak links in the chain will produce superior sonic results for less money. At Duelund prices, I am happy to use the world's next best coupling cap, and focus on other areas. Coupling caps, of course, are easy to replace and compare-- which may account for their cult-like following.
As to aftermarket clocks for Sony, I've thought about Ultraclock, and will email you directly regarding other options. |
Face,I have done this comparison (I also included V-Caps) and the Duelund VSF & the V-Caps are the winners. If you can get the CAST, go for it and be prepared for a whole new natural sound. For me and many other people with very demanding ears, the CAST is the very best.
Enjoy your comparison. I had a lot of fun doing it. |
Dave, I saw a picture of your SCD-1 and Im impress about the amount of work you have done to it, looks nice. You really like batteries:-)
I have seen & seriously compare other modded scd-1/scd-777 with add-in modules to bypass the analog stage and I honestly was not impress with the sound quality for the amount of money this boards cost. Dont get me wrong they do change the sound quality from the stock components but to my ears it was not pleasant.
The audio board on these sony models is well designed and as I mentioned before, in my experience, changing key stock electronic components is all it takes to make these players to deliver a sound quality to the level of any player costing over 15K. I always recommend putting most of your money on the entire audio signal path components (from the RF board to main board and to the last output wire (silver wire) on the audio board, of course there are other areas that need improvement.
Last year I purchased a used SCD-777 just in case I ever need spare parts, the previous owner have upgraded this player with Allen W. level 6 mod and while it did sound good compared to the stock components but I can not justify spending the asking price for the modules, I think they are extremely over priced.
BTW I noticed that you have the SC4 on your player, I used to have it too. If you are interested I can recommend a better clock module. The only issue might be that I live in Europe. |
If anyone happens to have a pair of 4.7uf VSF or Cast they'd like to part with, I'd be interested. |
Felix, I was told that by someone who has modded the stock SCD-1 analog stage instead of replacing it completely as I have. In any case, there are much better places than Duelund to put money and achieve profound results inside that Sony. |
In the next week or two I should be comparing Mundorf S/O, Claritycap MR's, and Duelund copper VSF's, I can't wait. |
Removing the two 2.2uF output stage caps is a big mistake (I know because I have tested). Replacing the op-amps with 627 plus the Duelund VSF will give a sound performance you can not imagine (I plan to use the CAST in the future).
The SCD-1 is an incredible player, the secret is to replace the right components, the clock is the only add-in board that I have installed, everything else I have done is about replacing the cheap components.
Cheers,
Felix |
Fas948, several modders of SCD-1 have simply removed coupling caps from output stage & observed no meaningful DC off-set. |
I forgot to mention that for my electronics Im using VSF DC and CAST 630V. The INPOL-2 is a well designed amp plus beautiful looking and these were the missing caps for one of the best integrated amp in the market IMHO.
Like with any amplifier, you really need to know what you are doing. Pathos will not share any technical information and on the INPOL-2 there are many sensitive areas (high voltage) that you need to be extreme careful.
|
I have just recently upgraded the caps on the pre-amp section on my Pathos INPOL-2 with Duelund VSF & the mighty CAST capacitors and I can not begin to describe in words how amazing these capacitors are. If anyone has the budget and space on a component go for the CAST. If you dont have the budget yet, save save save until you are able get them. Duelund CAST are the very best there is in the world of capacitors (audio signal path).
I am also using a pair of VSF on the output stage of my SCD-1 and the sound is just great. I would like to use the CAST but there is no space available. However I might consider an external setup in the future.
I have been lucky to audition many of the top capacitors in the market (audio note silver, V-Caps, Mundorf silver/gold/oil, etc.) and to my ears the CAST are the very best.
The CAST deliver the most natural sound, after 100 hours on burn-in time they start to show their sound beauty. |
Smglaw
I do not know about that on the passive parts the difference is 10x with Duelund from the x101d, to x100st and 500c. The difference in the caps is shocking. The Fishers sound similiar one better than the other but still from the same family. Maybe plastic caps are all similiar but Duelund caps from even Mundorf are the equivalent of going to tubes from SS or more. Duelund is in my opinion the biggest improvement I have ever heard. Like I have said before I wish I had CAST mid range caps that I ordered and not the VSF that came in. It was (at the time $400) and would be well worth every cent and I am cheap!
That being said I would like a Fisher CX2 and if it was 10% as much better than Fisher int as Duelund is over regular caps I will be thrilled!
Every person I have had over hearing these speakers have all had the same comment and that is "that is what caps do!" Everyone is shocked at the difference not one person has ever said I can hardly tell the difference. The difference is so huge that they take time to take it all in. Same reaction all the time was first 30 minutes liked the old caps after that they could not believe what caps can do and were just shocked. One friend just shook his head for an hour in complete disbelief.
I am actually taking the speakers on the road in the spring to a Audio get togther so that other Audio guys can hear them. It is so huge (and Klipsch are big) that I feel it is well worth it for them for me to take them.
I have rolled many kinds of tubes in (from the 5 Fishers I have) and consider that all small potatoes compared to the passive crossover caps. Steen has turned me into a believer, no doubt. I do not think anything as important as the passive speaker crossover parts. |
Some elements of the CX2 topology can be found in the X-202 and C series receivers. But no preamp section in the integrateds and receivers is the same as the CX2 (not even the X-1000). More importantly, none sounds as sweet and musical. The CX2 is the best stereo pre-amp Fisher ever made.
The more important point of all of this is that you should not allow the quest for perfect passives to overshadow the weight of active components and basic circuit topology. The latter has far more impact on the sound than the former. Before I would spend $1-2k on x-over capacitors, I would consider a CX2 implant (if you can even find one) or similar primary or active element system upgrade. Even $300 can buy a mountain of retubing.
Passives are like cables. They can help a good system perform better, but they will not transform a system suffering significant deficiencies elsewhere. And they can mess up what was an effective formula. Witness my earlier comments on the "Solenization" of vintage gear into tonal sterility. That some of your Fishers sounded so good to you on what are common grade passives should underscore that balance (even though they are stuffed full of beautiful Beyschlag carbon films).
Consider them as seasonings on the main dish. But they're not the meal. |
Dave I really liked Tempo's reviews more than Tony's as I found his confusing. When reading Tony's he gets the Duelund right, but not the magnitude. I do think the difference from Mundorf Supreme and Duelund VSF is huge! I think that is what Tempo is saying is the difference is HUGE but 3x may be strange wording. I also agree with Tempo as I found the Silver in Oil tilted the sound upwarded and (for me) I agree with Tempo and see no value in the Silver in Oil. Tony rates every more expensive Mundorf higher and many people I have heard do not like the Silver/Gold?
I wish Tony would come out with some adjusted numbers. I think only the best can be 10/10 and if he rates CAST the best (and I sure can not argue with that) than everything else should be less. I remember thinking a Sonicap would be good from Tony's rating of 8.5 and I think their crap! Tony rates nothing less than a 6 which is like all caps pass. Tempo at least says some are Tier F or whatever and that puts it into perspective. Tony's rating's give one a false sense of what they have.
Just more realistic numbers from Tony would be nice like a CAST at 10 VSF at 9, Supreme 6.5 and Sonicap at 5 and a Solen at 2 then if I read that I would know there was a difference in caps which there is. |
Sgmlaw
Is not the x202 the same pre-amp section as the famous 400CX2? It is interesting you say the 7591s are beefier it is exactly that I think is why I like them better. Tight defined bottom end. Interesting you say that about the tubes as well as I have told the tech guy who has the x101d not to move any of the miss mash of tubes from where they are as I think it sounds fantastic! |
Volleyguy,
Stereophile tends to like items that you can buy new in a salon. They are not going to recommend a harder to find, vintage production tube that is generally only available used. The EH 7591A is a "nice" output, better than the JJ in my opinion, the latter being a little tizzy on top at times. But its fat size aside, the EH simply does not present the midrange presence of a Westinghouse, or a coin base Sylvania for that matter. Also, none of the current production 7591As have the grid leakage tolerance of the older production. While potentially pricey, I would try to hunt down a good quad of old Westinghouses (old as in used/test strong, as brand new quads are quite rare). They will be a significant step up from an EH. They are also less likely to break down than an EH can in the wrong circuit.
The 7591A is an interesting tube. Some would say it is the least tube-like sounding output tube, and it was quite a marvel of engineering at the time, being one of the last major output designs. It will be punchier and go deeper than a 6BQ5, especially in a SS rectified Fisher. Because only two manufacturers produced it during the vintage era, whatever brand you locate will be a Sylvania if a coin-base, or a Westinghouse if not.
The beauty of a good 6BQ5 is its middle, which is unmatched in my opinion. It is not powerful, but you don't need great power with horns.
Just as with passives, it is sometimes good to mix small signal tubing across stages to a desired result. Using all of one manufacture can sometimes be counterproductive. One sage piece of advise if you intend to start rolling: buy used/test strong stock. It is MUCH cheaper and you will have much more variety to choose from than with NOS. And most used/strong tubes will last just as long as an NOS. It is also a lot more fun.
At this point, I do NOT recommend running any Fisher tube instrument bone stock. Repairing individual items as they fail is not a good course at this point. Again, go check the vintage forum archives at AA for particulars on what should be done. I know I've written a lot there over the years. In particular, once the bias supply is updated, any 7591A will lead a longer and much cooler life.
It really is not fair to compare the original X-101 with the later X-101-D until both have been properly reconditioned. The former is now 50 years old, and is in dire need of reconditioning. It is no wonder it may not sound competitive. But of that family, I prefer the X-101-B the best.
If you really want to enjoy the Fisher tube sound, the pinnacle is the 400CX2 preamp. In my main system, a fully restored example feeds a larger Classe/Thiel pairing to delightful effect. |
Volleyguy, Tony Gee has a better handle than Tempo on how to rate caps. With Tony's method there is modest bracket creep. Caps that once led the pack at a 10 rating have been gradually surpassed by 10-20% improvements, raising the benchmark for SOTA to around a 12-13 point rating. The incremental progress one hears with equipment at the top of the high end occurs within a class of products that is trying to close a narrow gap between 9/10s and 10/10s of what's possible in audio. To talk about 3x improvements at this level is rediculous and pretty much discounts one's credibility as a reviewer.
Rationalizing value is a different issue. If trying for that, I would be tempted to opine that a handful of $11 Texas Components TX2575 resistors in preamp is better value than a $2000 in xover capacitors. |
