Can an amp and pre amp become timeless?

[FT251]

I’ve been into hi resolution audio for 20+ years, well longer than that but acquired high quality gear about that time. I veered off into other interests for 15 years but still had my system sitting idle in it’s dedicated room. I became interested in it again 6 months ago and began to update it. I still have my Rega Planar 25 table and a Dragon phono stage. I retained my CEC TL1 transport, but replaced my DAC with a Dinafrips Venus II, I also have the Hermes DDC which I feed my CEC into as well as my Cambridge Streamer. I sold my Genesis V speakers because they were having an issue with the left channel bass and since they were out of business I had no way to fix them, it was over my head. I found someone that wanted them and was willing to repair them himself. (he is very happy with them) I replaced them with some Goldenear Triton 1.r’s which I love. So here is the nostalgia part. I still have my VAC Cla 1 Mk II pre amp and my VAC Renaissance 70/70 Mk II amp. I feel they still hold up well sonically, so my thoughts are to send them both to VAC for the Mk III updates this fall of 2022, which includes replacing any necessary parts and "voicing" them back to new as intended when they were first made. I really believe these pieces are worthy of the restoration, are newer pieces today really going to make much headway? I cannot afford to replace these items with "like" items as I am retired and the discretionary income isn’t there anymore. I just feel like they are still really good and offer a very high quality sound. I mean 8- 300 B tubes can’t be all that bad can they? I’ve voiced the pre amp with with Telefunken 12AX7’s and I have a small stash of them. Tube sound is still great right?

 

[Cellcbern]

I’ve been into hi resolution audio for 20+ years, well longer than that but acquired high quality gear about that time. I veered off into other interests for 15 years but still had my system sitting idle in it’s dedicated room. I became interested in it again 6 months ago and began to update it. I still have my Rega Planar 25 table and a Dragon phono stage. I retained my CEC TL1 transport, but replaced my DAC with a Dinafrips Venus II, I also have the Hermes DDC which I feed my CEC into as well as my Cambridge Streamer. I sold my Genesis V speakers because they were having an issue with the left channel bass and since they were out of business I had no way to fix them, it was over my head. I found someone that wanted them and was willing to repair them himself. (he is very happy with them) I replaced them with some Goldenear Triton 1.r’s which I love. So here is the nostalgia part. I still have my VAC Cla 1 Mk II pre amp and my VAC Renaissance 70/70 Mk II amp. I feel they still hold up well sonically, so my thoughts are to send them both to VAC for the Mk III updates this fall of 2022, which includes replacing any necessary parts and "voicing" them back to new as intended when they were first made. I really believe these pieces are worthy of the restoration, are newer pieces today really going to make much headway? I cannot afford to replace these items with "like" items as I am retired and the discretionary income isn’t there anymore. I just feel like they are still really good and offer a very high quality sound. I mean 8- 300 B tubes can’t be all that bad can they? I’ve voiced the pre amp with with Telefunken 12AX7’s and I have a small stash of them. Tube sound is still great right?

I would go beyond restoration and replace key caps, resistors, wiring etc. with better than stock (e.g., "world's best" Duelund tinned copper foil caps and Vishay Z-foil resistors) as I did with my modified Pathos TT integrated amp. See: https://www.whatsbestforum.com/threads/pathos-tt-rr-mods-upgrades-2.31972/#post-758602

If the circuit design is good upgrading the parts can not only result in a "timeless" component but also one that holds its own with the very best current designs.

 

[Atmasphere]

Tube sound is still great right?

Well sure. But is that the same as asking 'can I do better?' And 'if so, how much does it cost?'

 

[Cellcbern]

Assuming the circuit design is good to begin with, modification/upgrade has always been the most cost effective way to "do better" because unless you are talking about the handful of highest end mega-buck amplifiers, most manufacturers use cheap parts in order to design to a price point. However unless you are a skilled DIYer (I am not) you need a very good tech and/or factory assistance (I had both) to ensure a good result. If I were in your position I would send the components to VAC for the Mk. III upgrades and see how much difference that makes. I would also ask them what else beyond these upgrades they had considered or experimented with (e.g., that might have been too expensive to put into production) that might make further improvements (e.g., better caps and resistors). That is how I started with the Pathos factory. It was their recommendation to upgrade specific caps that got me started on the upgrade path with the amp. All total I have spent about half the current retail price of the Pathos TT (about $4K - parts and labor) on modifications, with the result that the modified Pathos TT is at a "last amp I'll ever buy" level of performance. If you want to experiment with solid state components, try auditioning Class D or other solid state power amplifiers with the upgraded VAC tube preamp. I have never heard an all solid state system I could live with long term and will always have tubes in the chain. Finally, if you haven't already done so buy several pairs of NOS 50's/60's 12AX7's and 12AU7's for the VAC preamp. Prices for vintage Amperex and Mullard preamp tubes have gotten crazy but you can still find some of the old American long plates at reasonable prices. I use Sylvania long black plate 12AX7's in the Pathos TT with outstanding results.

 

[microstrip]

Replacing components by more expensive components can either improve or ruin the sound of equipment. The sound of a component in a circuit is associated to its function and the circuit itself. Using other people opinions in different equipment is a risk.

In an hobby ruled by user preference DIY benefit from strong bias and accommodation factor - as we listen to partial changes we get used to the modifications. I have sometimes carried such upgrades in expensive equipment, but always advised by the manufacturer.

IMHO sending the VAC equipment to the manufacturer is an excellent idea.

 

[Atmasphere]

Assuming the circuit design is good to begin with, modification/upgrade has always been the most cost effective way to "do better" because unless you are talking about the handful of highest end mega-buck amplifiers, most manufacturers use cheap parts in order to design to a price point.

Sometime in the last 25 years or so the semiconductors needed to be able to design an amplifier that really allowed you to run enough feedback became available. Prior to that feedback had gotten a bad name in high end audio because the amps out there that used it didn't use enough- and adding more was really not practical because the designs lacked something called Gain Bandwidth Product. If you don't have enough of that, you can't run a lot of feedback either. Feedback, by its application will add higher ordered harmonics and IMD of its own, causing brightness and harshness (while looking good on paper). But if you can run enough feedback, this problem goes away.

So now there are solid state amps that sound perfectly smooth like a good tube amplifier, but more transparent owing to vastly lower distortion. I've found that a lot of people have a knee jerk reaction to the idea that there are now solid state amps that can do this, but take it from a manufacturer of tube amps for nearly 50 years that this is so. IMO the days of tube power amps are quite numbered on this account. Perhaps just in time!

 

[Cellcbern]

Sometime in the last 25 years or so the semiconductors needed to be able to design an amplifier that really allowed you to run enough feedback became available. Prior to that feedback had gotten a bad name in high end audio because the amps out there that used it didn't use enough- and adding more was really not practical because the designs lacked something called Gain Bandwidth Product. If you don't have enough of that, you can't run a lot of feedback either. Feedback, by its application will add higher ordered harmonics and IMD of its own, causing brightness and harshness (while looking good on paper). But if you can run enough feedback, this problem goes away.

So now there are solid state amps that sound perfectly smooth like a good tube amplifier, but more transparent owing to vastly lower distortion. I've found that a lot of people have a knee jerk reaction to the idea that there are now solid state amps that can do this, but take it from a manufacturer of tube amps for nearly 50 years that this is so. IMO the days of tube power amps are quite numbered on this account. Perhaps just in time!

"Smooth and transparent" are not enough for me. I have listened to a number of the new solid state amps including the new Gallium chip Class 'D' offerings, and to my ears they all lack the liquidity of tubes and sound a little clinical compared to the best tube/hybrid designs. I have heard a few hybrid tube/solid state amplification pairings (integrated amps and separates) that achieve the theoretical "best of both worlds" (including my own modified Pathos TT), but haven't heard all solid state amplification as yet that does. I will keep listening. By "perhaps just in time" I assume you are referring to the inevitable disappearance of NOS tubes. Yet new tube and hybrid components continue to be released as do new tubes modeled on the old. Personally I have enough NOS tubes in my "stash" to last the rest of my life.

 

[Atmasphere]

Smooth and transparent are not enough for me. I have listened to a number of the new solid state amps including the new Gallium chip Class 'D' offerings, and to my ears they all lack the liquidity of tubes and sound a little clinical compared to the best tube/hybrid designs.

To be clear simply because you've heard one class D amp, even those with GaNFET outputs, does not mean you've heard them all. I've heard some that are every bit as liquid and organic as the best tube equipment.

What makes this so in any amplifier is its distortion signature, what many audiophiles refer to as the 'sonic signature' of the amp. In order to sound smooth like you describe, the 2nd and 3rd harmonics must be high enough that they are able to mask the higher ordered harmonics; the latter of which are the cause of harshness and brightness in any amplifier- and yes, contribute to a 'clinical' quality. To give you an example of how this works, SETs are very smooth and organic but actually have more higher ordered harmonic distortion than almost any solid state amp. They get away with it because the lower ordered harmonics are so profound!

So even if the semiconductors exist, the designer still has to see to it that either the distortion is so low that the music itself can mask the distortion (IME this means the distortion must be over 105dB down; pretty difficult to do), else the deisgner needs to pay attention to the distortion spectra (sonic signature) rather than simply looking to decrease distortion as much as possible. IOW the designer needs to pay attention to how the human ear/brain system perceives sound and apply the engineering to that rather than simply designing to look good on paper.

 

[Cellcbern]

To be clear simply because you've heard one class D amp, even those with GaNFET outputs, does not mean you've heard them all. I've heard some that are every bit as liquid and organic as the best tube equipment.

What makes this so in any amplifier is its distortion signature, what many audiophiles refer to as the 'sonic signature' of the amp. In order to sound smooth like you describe, the 2nd and 3rd harmonics must be high enough that they are able to mask the higher ordered harmonics; the latter of which are the cause of harshness and brightness in any amplifier- and yes, contribute to a 'clinical' quality. To give you an example of how this works, SETs are very smooth and organic but actually have more higher ordered harmonic distortion than almost any solid state amp. They get away with it because the lower ordered harmonics are so profound!

So even if the semiconductors exist, the designer still has to see to it that either the distortion is so low that the music itself can mask the distortion (IME this means the distortion must be over 105dB down; pretty difficult to do), else the deisgner needs to pay attention to the distortion spectra (sonic signature) rather than simply looking to decrease distortion as much as possible. IOW the designer needs to pay attention to how the human ear/brain system perceives sound and apply the engineering to that rather than simply designing to look good on paper.

Which solid state designs are you referring to? Want to make sure I listen to them if I can.

 

[Atmasphere]

The AGD Audion has got nice comments in this regard. Some amps using the Purifi module do too, but you have to be careful as some people don't seem to get the input circuit right and that has to be correct for the module to show itself off. Of course we recently entered that market too.

 

[Cellcbern]

The AGD Audion has got nice comments in this regard. Some amps using the Purifi module do too, but you have to be careful as some people don't seem to get the input circuit right and that has to be correct for the module to show itself off. Of course we recently entered that market too.

Listened to the entire AGD line at Capital Audiofest while sitting and chatting with the designer. They were very good but my comments with regard to comparisons with the best tube/hybrid designs stand. I could live with an AGD amp paired with a tube preamp, but not an all AGD pairing.

 

[Atmasphere]

Listened to the entire AGD line at Capital Audiofest while sitting and chatting with the designer. They were very good but my comments with regard to comparisons with the best tube/hybrid designs stand. I could live with an AGD amp paired with a tube preamp, but not an all AGD pairing.

Yes, I get that. The only feedback I have on the AGD is coming from our customers who of course are using our preamps. Would you put a solid state preamp in your system with a tube amplifier?

 

[Solypsa]

@Atmasphere what advantage may a tube preamp hold over solid state preamp in 2022, in light of your comments on power amps?

Are you working on a solid state pre to compliment your class D amp?

 

[Atmasphere]

@Atmasphere what advantage may a tube preamp hold over solid state preamp in 2022, in light of your comments on power amps?

Are you working on a solid state pre to compliment your class D amp?

Good question! Preamps typically have far less distortion than power amps, so probably not much if any. Our preamps were the first balanced line preamps offered to home audio (1989) so I might take this in a slightly different way, which is that of supporting the balanced standard. I see very little of that in high end audio today even though there's a lot of balanced equipment now.

One advantage is that its a lot easier to design a tube phono section that won't make ticks and pops due to superior overload margins. IMO this has been a problem in a lot of solid state designs over the last 6 decades. I was quite surprised when I discovered how a phono preamp can do this- sounding for all the world as if the ticks and pops are on the surface of the LP! As a result I'm very used to little or no ticks and pops when playing LPs, despite not taking any particular steps other than using a dust brush before setting the needle down.

The other issue might be input impedances, although that seems like a weak argument to me. One advantage solid state often has is to employ a direct-coupled output, but our MP-1 and MP-3 have done that since their inception.

 

[Labpro]

I have an opportunity to demo AGD mono amps. Should I be concerned about using a tube preamp? Thanks for the advice.

 

[Cellcbern]

I have an opportunity to demo AGD mono amps. Should I be concerned about using a tube preamp? Thanks for the advice.

I sat with the designer and listened extensively to the full line of AGD amps at Capital Audiofest. As good as they are their sonic signature was too "solid state" for me when paired with the AGD preamp. I would not consider owning them unless they were paired with a tube preamp.

 

[astrotoy]

My Cary Signature 2A3 SET monoblocks are over 20 years. They still power my similarly aged Avantgarde Duos. Change power tubes about once every five years or so. I bought both around 20 years ago. My Pacific Microsonics Model Two ADAC is of similar age. I bought it about 12 years ago. My two Ampex ATR-102 tape recorders are over 40 years old. They lived most of their lives in recording studios until I bought them (out of two different recording studios) in 2016. Other parts of my system are newer.

Larry

 

[Labpro]

Interesting feedback. Thank you.

 

[Atmasphere]

I have an opportunity to demo AGD mono amps. Should I be concerned about using a tube preamp? Thanks for the advice.

No. We have a customer that really likes the combination.

 

[Labpro]

Thanks for the feedback.