Upgrading specific components in a tube amplifier

I have upgraded my Quicksilver Mono 60.

I have to admit -- it is VERY hard to compare how things sound after it’s been a while. Auditory memory is pretty bad. I think I hear differences but I have no control group to check. What I do know is that it's likely that I improved the sound.

That’s my approach to a lot in audio. Phrased as a motto:

Make improvements of a sufficient degree that I can have moderate confidence there is now better sound.

capacitors and resistors are generally easy.  focus on the signal path.  save the old components in case you don't like the new sound.  

tube sockets are a lot more work and probably get upgraded only when they become worn out.  Tube rolling, especially with old tubes with oxidized contacts, can degrade them.

Power supply upgrades generally require a better understanding of how it is designed so study and make sure you have an understanding of what you want to accoplish.

Jerry

Thank you for your replies. 

The audiophile gentleman I was talking about upgraded the capacitors to Arizona Capacitor Blue Cactus and resistors to Audio Note Silver Tantalum/Niobium 2 watt. Since this person is to specific I was wondering if the components had a significant and positive effect on the sound overall. 

I am still reflecting on purchasing the Yamamoto VT-52 amplifier and I have been told that they are absolutely astonishing but the tube sockets could be improved, that's why I also asked about those. 

In your experience, do such modifications lead to noticeable improvements in sound quality, or do they risk altering the original design in ways that might not be beneficial?

To answer the question.... It can, and It can.  Different components and manufacturers can have a different sound.  I've messed around with many different pieces of equipment over the years.

For example.  I have an older Dared MC-7P preamp that I picked up at a yard sale a few years ago.  This is a Chinese tube unit that sold for around $800 new 15 years ago.  It came with some crappy capacitors in it.  I replaced them with Mundorf and Clarity caps.  Oh, what a positive difference it made.  

Then I had a Classe Model 70 amp that sounded very nice.  Smooth, warm, good resolution, but a bit soft in the upper treble.  Someone recommended that I replace the several of the electrolytic caps with foil and teflon caps. As it was already showing it's age, I went ahead and recapped the amp.  It went to hell.  Bass got muddy and the treble went from soft to agonizingly bright.

So, the lesson I learned is that audio engineers sometimes make choices for specific reasons.  Sometimes it is for manufacturing issues or costs, sometimes for managing the sound or voice of the equipment. 

Do your research, ask questions,  take pictures and document your changes, in case you have to reverse what you did.  Don't be afraid of contacting the manufacturer and ask questions.  You will be suprised at what they may tell you to go ahead and do (or not do.)  Designer Nelson Pass is famous recommending upgrades to his older designs.  Same with Steve McCormack and the guys at Conrad Johnson.

And make sure you are making modifications for the right reasons. Are you doing it because you want to have fun and enjoy the hobby?  Are you making a repair and it is an opportunity to possibly improve a short coming? Are you dissatified with the piece of equipment?  [Would it be cheaper to sell the gear and invest the money (including what you might spend on parts and labor) into something better.  Can you afford to write off the investment in the equipment you are modifying?  (Somethimes it can be real hard to sell modified equipment.)]  

Just my 2 cents... wait, better make that a nickel since they want to stop making pennies, lol.

- Jeff

Different resistors and capacitors are popular for different applications.  Figure out which resistors and caps you're looking to upgrade, post the values and where they are in the circuit, and current brand, and you'll get some good recommendations.

Upgrading parts can certainly be worthwhile, and can be audible, but what you prefer is always subjective. Be aware that some caps take some time to burn in, and don’t always sound better immediately.

For me, recent mods started with adding a VTA board to my Dyna 70s. In addition to a different driver stage, those mods also beefed up the power supply. At the same time, I upgraded the coupling caps, resistors, and internal wire. It’s tough to be certain what contributed to specific changes, but the whole amp sounded better across the board to me. Switching to a solid state rectifier followed.

Tube rolling can lead to some significant audible changes too, and while not usually inexpensive, they don’t typically involve any modification, assuming the amp will accept the tubes types you try, so it’s easy to experiment if you’re willing to obtain the tubes.

Lastly, my tube amps are now bi-amped, have an inline high pass filter before the amps, and only power the midbass and tweeters from ~ 60hz up. The woofers go through an active low pass crossover and are powered by a SS amp below 60hz. Relieving the smallish tube amps of the responsibility of powering larger woofers in the lowest octaves most definitely led to improved clarity, and in my case was relatively easy and affordable to do.

Once again thank you very much for taking your time to write so thorough responses to my inquiry. 

 

Are you doing it because you want to have fun and enjoy the hobby?  Are you making a repair and it is an opportunity to possibly improve a short coming? Are you dissatified with the piece of equipment?  [Would it be cheaper to sell the gear and invest the money (including what you might spend on parts and labor) into something better.  Can you afford to write off the investment in the equipment you are modifying?  (Somethimes it can be real hard to sell modified equipment.)]  

Relevant and necessary reflections that I believe one should carefully consider oneself before proceeding with these major adjustments.

Figure out which resistors and caps you're looking to upgrade, post the values and where they are in the circuit, and current brand, and you'll get some good recommendations.

As I mentioned I'm considering Yamamoto Sound Craft VT-52. It is supposed to be an astonishing amplifier made of high quality craftsmanship.

After reading the article of switching components here and there, I started wondering how that would work on a Yamamoto amplifier. II have a pair of Audio Note speakers, entry-level, although they may be upgraded to AN SPe/HE very soon. Then I started to play with the thought of changing bits of Yamamoto to Audio Note components (capacitors, resistors and perhaps tube sockets as I heard Yamamotos aren't the best) to see if you could improve the amplifier a tiny bit. Perhaps it could also promote synergy with my speakers, who knows... 

The intent is not to have a Yamamoto amplifier that becomes a clone of Audio Note but rather, identify if there are components within the Yamamoto circuit that could be improved. 

Having overhauled a vintage tube amp from the chasis down, I would say the 3 most noticeable component improvements were the big smoothing caps, any  old wax caps and  the big one... tubes!  It was obvious when it happened but it took me 4 years to find a good strong set of vintage Japanese tubes for a vintage Japanese amp. And no doubt a british built amp would sound best with tubes made in the UK of that era also. 

Many of you mention tube rolling and I can't wait to indulge in this exciting activity, even though it seems it won't be as cheap as somebody claims. The Yamamoto amplifier I'm looking at uses the exotic and rare VT-52. 

Perhaps I should try to restate my question and present it in a hypothetical way.

If I were to switch resistors to Audio Note Silver Tantalum/Niobium 2 watt, change the output capacitors to Audio Note silver foil capacitors and change the tube sockets to Audio Note aluminium/steatite bases in a Yamamoto amplifier. Would it have significant changes to the presentation of the music? Please bear in mind this is a thought experiment. 

@carlsbad2 Thanks for the detailed information in your posts. What’s your answer to the other question the OP asked:

In your experience, do such modifications lead to noticeable improvements in sound quality?

I don’t see that you’ve relayed what you’ve found noticeable and I think this is a key trigger point for the OP (and others). Given your technical expertise, I’d love to learn about your subjective impressions of, say, how much a capacitor or other change leads to improvements which can be heard.

@apollinaire - just to continue the thought experiment....

resistors - I would think that would depend on what resistors are currently in the Yamamoto and which ones are in the signal path. Considering the price point you are at, the existing resistors are probably not trash.  Thus I would think only minimal improvement or difference.

capacitors - Probably the most likely to change the sound/voicing of the amp.  Again, depends what is in there now and where in the signal path.  Would it be better or worse? or just be different?

tube sockets - I would think it would be minimal change in sound, if any.  Changing them may be more about durability than sound quality, especially if you are swapping tubes a lot.  (At the price range the Yamamoto is in, I would think they are not using 25 cent, bulk purchased by the shipping container, sockets used in the $300 Chinese integrateds on eBay.  (No offence to the builders of said units.  We understand you have price points you have to meet.)

I upgraded my 45, 2A3, 300B, and 845 SE amps cathode RC circuit with transistor/MOSFET shunt regulator circuit. I can now adjust the cathode bias voltage for the power tubes. 

The sound quality improves significant with superb clarity. Real cool.

From pics I can find on line, the Yamamoto VT-52 amp has some impressive parts quality underneath compared to most.  Not saying nothing can be improved, or that you won't like the sound of some different parts better, but it already appears to be fairly evolved, and isn't exactly loaded with low hanging fruit.  

Have tried isolation feet under it?

@hilde45 

"Make improvements of a sufficient degree that I can have moderate confidence there is now better sound."

I agree with the sentiment, for the exactly same reasons. Especially as the "improvements" become more subtle. 

I tend to live life the same way.

Make good life choices and you'll live a longer and happier life.

Exclusive Audio of Japan says this about the Yamamoto VT-52,

"The capacitors and resistors used are carefully selected from all over the world with the best sound quality selected through auditioning"

Is this the insides of the amp you want to make cap changes to, and why again?

You're looking at adding quite a bit of silver with the Audio Note components you specified in your post. I'd expect this may thin out mids, bass, less warm presentation. I have no issues with silver, just needs to be balanced with copper. On the other hand if existing presentation excess warmth or dark sounding silver could be just the thing.

Many nice caps out there including the Audio Notes. My favorites are the Duelund Cast tin plated copper. Also very much like Takman carbon film, some like the metal film. My favorite for max resolution/transparency are Texas Components TX2575 (nude Vishay). I'm using both the TX2575 and Cast caps in my 300B monoblocks.

Should have statedTakman and Texas Components are resistors. Tubes can make a large difference as well, especially power tubes.

Thank you all for all of your insights.

I have read numerous articles, reviews and threads on various forums that confirms the high quality of Yamamoto and I don't think at all there would be a reason to change anything at all. It was just a thought experiment to get an idea of the possible outcomes of changing components as capacitors, resistors and tube sockets. 

You're looking at adding quite a bit of silver with the Audio Note components you specified in your post. I'd expect this may thin out mids, bass, less warm presentation. I have no issues with silver, just needs to be balanced with copper. On the other hand if existing presentation excess warmth or dark sounding silver could be just the thing.

This is quite interesting. It seems that a lot of people strive for an all silver situation in Audio Note forums, but somehow I'm starting to believe that silver might have a too bright, clean and neutral resolution, whereas I prefer a much more deep, flavorful and colored sound (without it being too dramatic, rather more natural and romantic if one can say that). 

It depends on design of the amp. SET with no feedback can be more sensitive to component change. But you also need to consider how those components work together in the amp. I.e. it could be that a X brand cap for one stage + a Y brand cap for the other stage that gives you a better sound. 

@apollinaire ..."Then I started to play with the thought of changing bits of Yamamoto to Audio Note components (capacitors, resistors and perhaps tube sockets as I heard Yamamotos aren’t the best)"..

Here is a thought mentioned on the other thread. Skip the Yamamoto 3w+3w amp and buy an AudioNote OTO SE 10w amplifier to go along with your desired AN speakers you mention. You can order it with proven caps and resistors, no guessing and screwing around. They come up 2nd hand used rarely.

Truly - this will save you a ton of wasted time and guess work allowing you to start listening to speakers/amp/parts components inside all designed to work together from the get-go. I only share this IF your real goal is not fooling with widget component changes and more about listening to music sooner. They spend 1000s of hours testing/trying/listening to their designs.

Many of us here here swap caps/diodes/resistors thinking we can outsmart the original amp designers, and it works sometimes, not all of the time. In the case of AudioNote amps/speakers working together well, Peter and team at AN truly know what they are doing. Go listen and compare at a show if you can somehow.  Just a timesaver tip fwiw, best of luck.

I have been considering the OTO SE amplifier, which is widely regarded as an excellent choice, and I can certainly understand why. I had the opportunity to listen to it recently, and I really enjoyed its sound.

That said, there is something I am trying to better understand.

The OTO SE is undoubtedly a great amplifier, but it does not, for example, include a completely negative-feedback-free signal pathway. To achieve that, one would need to look at the Jinro or higher-tier models, which come at a significantly higher cost. I have also contemplated investing in a higher model, but I often find myself considering how many concert tickets and vinyl records I could purchase with that amount. Ultimately, my passion for audio is rooted in a deep love for music.

Recently, I have come across smaller manufacturers, such as Yamamoto and Audio Tekne, who seem to produce high-quality amplifiers at a different price point compared to Audio Note. I fully appreciate the immense costs involved in running a company as comprehensive as Audio Note, which manufactures all its components in-house and offers numerous variations of each amplifier. Their reputation and craftsmanship naturally contribute to their pricing, which I completely respect.

However, I wonder if it might also be worthwhile to explore the work of dedicated, passionate independent producers, particularly those in Japan, who bring a similarly high level of artistry and commitment to their craft. I hope it makes sense.

Hey @apollinaire you are not wrong in looking to upgrade parts inside an amp. Lots of gains to be made at most price points. First off your connection points of RCA inputs and speaker binding posts, check out KLE or WBT. Super low mass designs that are a bit finicky to solder but make great gains in increased clarity right off the bat. Next make sure your internal wiring is super well separated for power vs signal wire. Tight spaces can lead to increased noise that is easy to remedy.

Next up you were talking signal path capacitors, and those could and should be changed but ONLY after you have a baseline what the amp sounds like. As @sns stated, going with AN silver caps could be awesome (and $$$!) they could also voice the amp pretty thin and not what you want. Get some time on the amp and listen for what you'd like to improve. More detail, more body, more transient speed, etc. I'd advise looking at neutral sounding copper film caps as space allows. Some of those can get pretty big . Look at Audyn True Copper Max, Duelund CAST CuSn, A.N. Copper, etc. for a very balanced and clean tone. If you need a little heightened treble, you can check Mundorf S/G/O. If you need super snappy transients and clean tone look at VCap ODAM which are great on size as well. Point being, listen to what you'd like to fix and adjust accordingly.

Good luck with the mods!

-Lloyd

@apollinaire ...but it does not, for example, include a completely negative-feedback-free signal pathway. ".

Zero, negative, local, global feedback, and more debated here over the decades on Audiogon. Search and check out some of the long threads about this too.

Regardless of the amp designer and circuit design chosen, I always go back to what sounds most musical to my ears given different tube sets and speaker pairing too.

As long as you know what sort of sound you are looking for, you are well on your way, and enjoy the music!