@atmasphere I see some assumptions on your part which could probably come from a misunderstanding. First off, I love the SIT-3 amp. Low volume, high volume, I love the amp all the way. What C-1 does, it allows SIT-3 to play louder (if and when needed), but SIT-3 does extremely well at even the lower levels. In short: at no point I voiced any dissatisfaction with SIT-3, but emphasized the synergy between the vfet pre and vfet amp. About C-1: my unit is fully restored and with SIT-3 I use it with all tone controls defeated (including loudness). If you have not heard the line stage of a C-1, I wish you have the opportunity to do one day. I am also thinking that if you like tube preamps, you will be in for a pleasant surprise listening to a vfet preamp :) Tone controls in the C-1 come in handy with certain amplifiers, or to tune in the room. I did not find it necessary to use any of the tome controls with SIT-3. About the simplicity of design: The simplicity of design can be argued back and forth. Designers have learned since the 70s and are able to simplify modern designs. Also, certain components are built better today then were built in the 70'. All that is true but also many things done in the 70' have been forgotten. In the case of Yamaha, most of the complexity comes in the form of circuit protection of sorts...quite crazy in the case of the B-1 for example, or tons of features in the C-1 pre, which at first glance is the anthesis of "wire-with'-gain". Some features of the 70's amplifiers are probably there just because the marketing department wanted them to be there. Some of these features can be defeated or carefully bypassed. Additionally, after 40+ years of use, some of the original ancillary components are at the end of their functional life and can be substituted for better components built today, and one can use the 70's vfet amps the proper way ;) and ensure that it would ran for many more years to come. Making a side note here: complex or not, these 70's amps run for 40+ years already. I giggle when I hear some manufacturers marketing claims related to 20 years warranty as if that would be of any relevance....yet you see many consumers basing their opinion of brand preference based on such irrelevance. What is important in the end is what the amp sounds like and will the amp be around long enough for the owner to enjoy it. That is simply the ultimate test, right? One could argue for instance, that SIT-3 has relatively high THD, right? But if most of the harmonics are of the even kind and if overall the amp sound as good as it does, how important are the technicalities? Same goes for the Yamaha or Sony amps...yes more stages, NFB, etc...but if the amp sounds good, why do technicalities matter? As far as I know, there is no scientific proof or empirical evidence that just for being simple, it must also sound best. Since we are talking about Yamaha, one of their other statement pieces, the MX-10000, is one of the most revered amps of all times. Yet, it is one of the most complex designs I am aware of, has stupid low THD, but in the end, it sounds phenomenal and can pretty much drive any load speaker. I hope I was able to clear any misunderstanding. I am a fan of anything that sounds good to my ears, agnostic of how complex or simple it was built, in technical terms :) |
Pass Labs SIT amps are very appealing. The warm and full sound seem to be consistent across most
vfet amps and the resemblance to the "tube sound" is not by coincidence
since the SIT I-V curve characteristics are similar to those of a triode.
The list of my curent SIT Amps collection: Yamaha B1, B2, B3 (C1 preamp) Sony TA-N7, TA-N8550, TA-5650 Victor (JVC) JM-S7 Sansui BA-1000 Lo-D (Hitachi) HA-500F |
@ericteh , I now have a First Watt SIT-3 in my room right next to the other Vfet amps :) I concur that it has great finesse and yes, it is a low gain amplifier. The low gain is not a problem if you ran the SIT-3 with the proper preamp and efficient speakers. I have the SIT-3 hooked up to a Yamaha C-1 that can push out like 3v, For speakers I am using Yamaha NS-2000 that are 90dB+ . The all vfet sound of the preamp and the amp is addictive. An excellent match for the Beryllium drivers of the NS-2k.. |
@jayrossi13 , thanks for sharing! re: " I mostly listen at reasonable volumes (70 db to 80 db range) and find the music doesn’t have to be loud to sound good. " and re: " Which is "better" would be a matter of a coin toss. " I personally prefer finesse and quality over brute force. However, I am spoiled to have both with either one of the classic vfet amps...The finesse and airy sound of SIT-3, plus the "whoomph" to shake things when required. |
@atmasphere Thanks for your feedback on trying a tube preamp. A luxman tube pre has been on my crosshairs for a long time and will probably bring one in soon. As far as the C-1, I am not sure what you mean by: " Your Yamaha is outclassed by the amplifier" ?? would you define "outclassed"?? The SIT-3 needs a preamp with sufficient gain to come alive. The C-1 provides that plus C-1 is the only vfet preamp ever build. The synergy between the vfet preamp and the vfet amp, is something to be heard. You should try that combo if you have a chance. I have not tried other preamp yet because the C-1/SIT-3 combo sounds superb. If I want "more" I can switch out the SIT-3 with one of the B amps from Yamaha, which have the similar airy sound and distinct vfet warmth, but much more headroom and authority. BTW, my C-1 and other vfet gear is fully restored and sounds the way Yamaha intended it to sound ;) |
just to ground on reality a bit, If you have not fully restored these units, you are really hearing the impact of aging on these units and comparing that is really subjective. Simply getting the ~45 years old amplifiers stable enough to power on and play music might not equate to an accurate representation. Speaking of the TA-N7 alone, N7 is a superb amplifier, but there are noticeable differences even between N7 units with different degrees of restoration, leave alone comparing them to other units. Speakers you pair them with is also a critical factor as N7s will not do as well on hungrier loads. The N-7 fully and properly restored with bulk caps replaced and a critical set of ill fated semiconductors will fare well against most amps, including its vfet rivals from Yamaha and others. To the same token, a properly restored Yamaha such as a B-2, will give the N-7 a full run for the money. After many hours of listening and tweaking these machines, both on the bench and the listening room, I find the N7 is very precise with a tight bass and airy highs. On the same token, the B-2 goes deep in the lows and has a clear advantage here, especially when pushing anything lower than 8ohms, yet keeping comparable on the highs and separation / depth, but with a wider soundstage. I can't say that I would trade one over the other so for this reason I will keep both..as a matter of fact I will be keeping two of each. If you liked the dual B3s in BTL, you need to hear 2xB2s or 2xN7s bi-amped. My hypothesis is that 2XB3 bi-amped do better than 2xB3s BTL, which is something I am yet to find time for setting up.
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Both, the B-3 and the JM-S7, are fantastic amps. I can't agree more about the sound signature of the B-3. Unfortunately for you, now you are tainted by the vfet virus and I have a prediction to make that your vfet collection will gradually grow :) I have most of all Vfet amps ever made and I never get tires of listening to them. B-3s are special indeed and besides the Sansui BA-1000s, they are the only vfet amps that could be used in BTL mode, albeit, if you have hungry speakers, the B-3 or the BA-1000s are not the best choice, while using them in BTL mode. You will also enjoy the Victor but the sound signature of the NEC vfets is different than that of the Yamaha. Note that all three of your amps will need restoration soon. |
The TA-N7 is the one to have. It sounds excellent. Very clean and transparent. Different signature than the TA-N8550 which has a lot warmer sound. I did have a N88, but did not keep it because it had issues and I did not want to spend the time to fix it at the time, so I sent it back. Eventually I will get another one. My friends who have both, the N-7 and N-88, give the N-7 the edge in versatility and overall sound performance. My understanding is that the N88 could sound good too, but it requires more thought on system matching. |
yeah, I read some different opinions and I will not try to justify why anyone would state that, other that they had units of different conditions, or did not perform true A/B listening. In my system where the amp would be the only variable, a properly restored B-2 or B-1 will sound same or better in most situation than a B-3 or B-3 duo. The problem with the B-2 or the B-1 is that they require lots more work and some simplification to bring them back to prime. The simplification part would actually allow for by-passing some of the selector functions and streamline the signal path. This brings them to a simpler signal path level, similar to that of the B-3 (or TA-N7, JM-S7, TA-8550, BA-1000, SIT-3, for that matter). I spend countless hours of A/B listening to most V-fet amps ever made. One thing I can say is that ALL of them are very engaging, where some would sound different than others or have more authority, but the differences are subtle. Another out-right statement I can make based on my listening impressions is that none of the other amps matches the B-1 in terms of sound stage and 3D of depth. The low-end of the B-1 could be blurry if the wrong type bulk caps are used. This is true for all the others, but it is more noticeable with the B-1. An important callout is that during the restoration, if the wrong replacement parts are used, that WILL impact the sound signature of the unit and not in a good way. For my restorations, I keep a well preserved and mildly refreshed original unit of each model as frame of reference for the other units I am restoring. During the restoration process I do not introduce any components that would negatively impact the sound signature of the original. Sadly, replacing components just for the sake of replacement, is a practice wildly popular which in most cases would actually cause a "rebuilt" unit to sound worse than the original. |
Hello PR, Actually there are a few vfet connoisseurs in France....but I agree that vfet units are so exotic and very much extinct...unless you find a vintage unit and have it properly restored. Nelson Pass has some newer offerings, but those are becoming rare as well. I agree with you about the using a different preamp and not the one in the ta-5650. The Lampizator is in a different class and I am not surprised you like it so much. I am aware of Lukasz and his creations, but I do not own any yet. About the ta-n88: I agree it could be a bit too transparent but it is a good preamp, nonetheless for those that like that level of transparency. If you have not had it serviced yet, that could also be a reason why it might sound "dry/sterile". Also, if not serviced, your unit could experience PSU failure (some zener diodes in there are ill-fated) that could take out the transformers. |
@kitr, Yes, the TA-N7 has the veractor "diodes" / death diodes, but it also suffers of problems with fusible resistors. The thermal runaway of those fusible resistors is horrible and over time they drift substantially from the original value. When they drift past a certain point, they will take out a vfet or two. Also, the BJTs in the final stage need to be replaced as they are also known to fail. Net, Net, while the TA-N7 does not have the death rate of the n4650/n5650, it needs to be restored nonetheless. The problem is that there are very few techs that fully understand vfet units and even fewer who would take vfet units for service or restoration. This is valid for all vfet units. Depending of where you are located (I mean on which continent) I could point you to someone qualified to service your units. |
Yes, Victor JM-S7 is a Vfet amp (sse above) Victor JP-S7 It is not a Vfet pre-amp Sony TA-5650 has a vfet in the pre-amp section, but I can't really call that a vfet preamp @kitr, The Yamaha C-1 is the only vfet preamp ever made, all the way to unique vfets made for, used only in the C-1 and nothing else. The C-1 it is also an absolute statement piece in terms of sound and it is my ultimate preamp and the frame of reference I use, when I compare anything else I get to listen to. While I did not try every preamp on the face of the earth, I did try a few...and to date, none gave me more pleasure of listening to, than the C-1. IMHO, the C-1 is really in a class of its own and even at 40+ years old, there are very few amps (new or vintage) that can equal its sound performance. Side note: I have restored more C-1s than very much anyone else except the Yamaha centers and one tech in France. The restoration process is an adventure of its-own. Extremely intense from an effort perspective and there is ZERO room for error. Most of the units I restored were fully working even after 40+ years which is a statement on its own, considering the C-1 is a complex beast in terms of the many options it has....all working just fine, if you ever need them, or bypass if you are a wire-with-gain seeker. Some units needed repair and some were of the worse case scenario, but all C-1s I restored are now singing like new, or better :) The C-1 is built like a tank, but some of the ancillary components are ill-fated and when they fail, they could take out a vfet or more. That said, any piece of audio equipment would need restoration after 40+ years and while the failure rate of the C-1 or other Yamaha vfet units is actually very low comparing to that of any manufacturer, it is still a good idea to provide preventive maintenance. It is amusing to see how some manufacturers use something like a 20-years warranty as a sale's pitch and also sad that many consumers fail for it. Maybe for newer equipment that is full of digital stuff is a valid pitch, but for the analog stuff that is alive and kicking after 40+ years, what good would a 20-year warranty do? |
@atmasphere maybe there is some enthusiasm in @kitr statement but it is not inaccurate. Most vfet amps will ride right along the top 1%-5% of the amps build new or old, in terms of sound finesse and detail. True, none will win any races for driving difficult loads (much below 4 ohms), but for average to efficient speakers, they are extremely difficult to match by other SS amps and some of the vfet amps do just fine against vacuumed glass. If you have the opportunity, you should try to pickup something like a B-3 or a B-2. For the B-2, I would send you something that would take care of the "stuff" in the signal path, so that there is nothing between the rear input and the driver board. B-2, B-3 are DC amps. Most of the ancillary circuitry is about protection, which actually works quite well, hence the high survival rate of these amps after 40+ years. Don't worry too much about too many stages or other "old school" amp design. If you have the opportunity, try getting one and if it is still kickin' even in original condition the sound is extremely engaging. With some proper TLC, they are world-class amps. |
@kitr, you are starting to build a vfet geat collection that is quite impressive. Congrats on your recent purchases! Any of the gear you called out can be repaired if the vfets are still OK, with C-1 being the most difficult to repair out of the rest. Restoring them to proper order, is quite a different thing than just getting them to work again. I am glad you got the B-2 to work again and thanks for sharing your listening impressions. Depending on how the B-2 was restored / repaired, will determine if it would sound noticeable different than the B-3 or B-3 x 2/ BTL mode. Key aspects of the B-2 restoration are the choice of bulk caps replacements and how the selector assembly is addressed. B-3 is simpler and does not have the selector assembly issue B-2 has. In BTL mode the B-3s might sound different to you but will have difficulty driving any difficult loads (below 6 ohms). That is not the case with a B-2. The warmer sound and soundstage of B3 in BTL mode might be a matter of speaker marching as the vfets of the B2 and B3 are technically the same and the circuit design is also mostly similar. I found that I actually prefer the B-2 over the 2 x B-3s in my system, and I did extensive real time A/B listening with no variables other than the amplifiers, so I guess is a matter of system synergy?? additional observations: If the C-1 you bought was listed as non-functional, if it is one of the units sold at the auction site in JP recently, CAUTION on who you take it to for repair! Do not take it to the corner tech / shop for repair or you will be sorry. You must make sure that you specifically ask the tech if he has experience with this unit...not with other Vfet units, but specifically with the C-1. Otherwise you will be sorry. The AK forum is full of such stories where a "tech with 30+ years of experience" takes on the job, just so that he returns the unit to the owner with fried unobtanium small vfets. C-1 has multiple types of small vfets, some only used in this unit and nearly impossible to source if gonne bad. You will find one person in the US that still works on these, one in Canada and a couple in Europe. Amp8 in Japan would also take on these units. The TA-N88 uses a pulse lock PSU that has the tendency to self destruct....which takes out a vfet or two. Hoping that is not the case and that yours can be repaired. For the Hitachi, there is no service manual or schematic available. Someone on a JP forum back-engineered the schematic but use that at your own risk as I do not believe it is fully accurate or complete...I couldn’t find the link at the moment. Good luck with all your units. I hope you get them properly serviced and restored so that they provide you with sweet vfet musical bliss for the next 40 years! |
hi @fiesta75 the B-2X is a really nice amplifier indeed. I have compared in the sense that I do have a couple of B-2Xs amps and I am well aware of their sonic qualities but my units are not fully restored yet and it would be immature to state an opinion, one way or another, between my B-2Xs and the vfet units. @kitr I have no doubt your units are in OK working condition. Full restoration with the specific key components addressed is a bit more than just a refresher and a recap. As and example, the B-2 you compared to the 2XB3s and others, based on your video, that B-2 looked like it was no where near the state of back to prime (e.g original ill fated drivers and pre-drivers, original signal path routed via the original selector robbing you of details, etc). Comparing that B2 with anything else would only yield an opinion on the effective age of two different units and not how they would work in prime condition. This is particularly important is when you compare vintage units with modern gear.... it is important they have relatively close effective age so that the actual age can be ignored, rendered a non-factor. As far as properly restoring a TA-N7 or the B-3s, our definitions of proper restorations might vary. All I can tell you is that it is not as simple as replacing a bunch of parts and hoping it will sound OK. It is not about the bench tests either. It takes a good amount of time and research to make an already good sounding amp sound excellent. I have listen to all of those amps and very much any vfet amp ever made, and have done it numerous times, with different units in different conditions, with various degrees of restoration, etc. Based on what I know today, I do not think I could come up with a similar pecking order, as that pecking order would have changed at least half dozen times over the years as I learned more about these units...their strengths and weaknesses, areas of improvement / that must be addressed, etc. Then the rest of the other relevant factors would compound the problem even further..., such as the rest of the system components which could work with one amp but not the others (B2 and sissy preamps is an example that comes to mind...B-2 can sound awful with certain preamps..ask me how I know), the type of music, etc. Last but not list, the audio memory comes in play. We as human have a surprisingly short audio memory..so comparing something I heard a few months back with something I would be listening at today, it is no way a relevant comparison. Now, those are things I learned based on my personal experience, based on my curiosity and depth of involvement with these vfet amps over the years which is extensive, yet it is not general by any means BUT, if I learned one thing for certain is that coming up with a specific pecking order would have to be done with the all the amps at the same listening session and with all other things being equal and even that might prove to be difficult. For similar reasons I will never state who I think is the most beautiful woman in the world or which vfet amp sounds best ;)
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Hi @kitri I am glad to hear you have the Hitachi sorted out 👍 I also want to point out that it is possible to make the amp sound worse than they actually did when new, if critical components ate not replaced with proper replacements. That said, your assessment of the Hitachi vs the Yamahas, is just about right. About the C-1 and the Sony, I hope you find someone qualified for the job. Remember, if something wrong with any of the Sony vfets, there is still a possibility you might get it to work again. That changes drastically when it comes to the C-1. Yamaha has service bulletins out for the C-1 that must be implemented, depending on the serial number of the unit, otherwise you might end up with a beautiful door stopper. I wish you good luck in bringing those two statement pieces back to prime. |
@kitr let us know. but do not be surprised if your friend ends up selling his Accuphase after that session.....my friend ended up selling his A-65 after a similar experience with a vfet amp. |
re: "It's really odd that the contemporary top of the line amplifier sounds worse than 45 year old piece." Not add at all and your expereince is not unique. I withnesed various astute audiophiles having similar reaction and favoring Vfet amps over some TOTL equipment of the likes of Accuphase, AR, Merrill, etc. The vfet amps of the 70s were build with parts that were some of the most linear amplification defices ever conceived. Unfortunately, they prooved too expensive to produce and were ultimately detroned in favor of Mosfets, BJTs, etc, due to cost of production advantaged. Nelson is the last amp designer that offically worked with new vfets in his FirstWatt series, which are also great sounding amplifiers, but due to limited supply of vfets, the production of theose units stopped as well.
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mjw25a, FW_SIT3 2nd harmonic is significantly dominant over the rest of the higher order harmonics. I do not believe that any more dominance of the 2nd would add any benefit. I have studied this quite a bit...on the bench with a proper audio analyzer and most importantly side by side comparison with other vfet amps. I can't wait for your impressions of the new amp. Based on the few photos I see on the net it looks like a nice project and of good quality too. Please share your impressions.
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@sp33ls , Awesome! Super happy for your experience and I like the quality of your build. rottalpha on AK and DIYa.. aka Atelier Hi-Fi on the tube |
ha ha, but it is not about measurements to see if it is built right as I think your amp looks to be built more than right. I did go a bit through the forum and I am tempted to build the same amp...I sure have plenty of tokin devices to do it... I did find some harmonics profiles of the amp posted by ZM and I do appreciate the 2nd harmonic dominance over the rest of the range. Very similar to that of the FW3, which leads me to believe that it sounds very very good at low volumes...maybe up to ~5w, then the THD starts to play a factor..once it tips the 1%+ scale. But that is to be expected since there is no NFB. I was hoping to win the auction on the Sony builds, but I guess I will just have to find a suitable alternative to build...so I did consider the sissysit3 ;) BTW, listening to a "refreshed" Yamaha B-3 now ...read: BIG SMILE ON MY FACE.
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