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Too Many Tubes?

More as a thought experiment than as a description of an actual problem that may or may not exist...

Has anyone ever considred if there might be a problem with too many tubes in a given system? How many tubes is too many, and what might be some issues that could have a detrimental effect on system sound quality?

What do I mean by too many tubes?
1- too many physical tubes (by quantity). Consider an example where you have (let's say) 20 or more physical tubes distributed in your power amp, pre-amp, phono stage and DAC. Besides the obvious potential issues with heat and the cost of rolling and replacing so many tubes, what are the disadvantages (if any) of utilizing so many tubes?

2- Same question, but this time the concern is not the physical number of tubes but the variety of tube types used in a given system. Can anyone make an argument against (or for) using a large variety of tube types in a single system?

For years I used a system with a SS amp (Krell, then McCormack) and ARC tube pre and phono stage. The ARC gear used the same 6922 tubes, and it there was a well-defined (not necessarily great) sonic signature. It was also very easy to tell when a given tube was microphonic or going bad.

Lately, I have been swapping a lot of new (to me) used gear in and out, and the all-tube setups have varied from SET to integrated tube amps w/ phono to all CJ tube seperates. All good... well, mostly, but I have noticed that in the setups with many tubes and/or many tube types it is can be hard to pick out the characteristics of a single tube or tube type. I am not saying that that is good or bad - it just is what it is.

Comments?
br3098

Showing 4 responses by mapman

mapman's avatar
mapman
21,870 posts
 
Old Armstrong stuff sound fantastic in my digital rig. Only three tubes in the signal path for digital in my system (the ARC sp16 pre-amp). There are 3 more (12AX7 I believe) tubes in the phono stage of the ARC pre-amp and that works quite well also.

I have a tube DAC I moved from my main system into my other system which is all SS otherwise.

I listen to everything from old jazz to classical to modern rock/pop and even hip-hop, so neutral performance for all genres is a big requirement for me.
mapman's avatar
mapman
21,870 posts
 
If you like them and you have a tube tester when needed, maybe not.
mapman's avatar
mapman
21,870 posts
 
It's funny how many audio people are able to accept the benefits of tube rolling and its effect on sound for better or for worse but cannot digest other approaches to customizing the sound, like digital signal processing, tone controls, etc.

The results always speak for themselves and there are so many ways to tweak to get what you want.

So, it's just funny....
mapman's avatar
mapman
21,870 posts
 
"tube rolling & DSP are fundamentally different in that tubes may hv additive or subtractive characteristics in specific freq ranges, but they do not introduce addt'l layers of circuitry, s/ware algorithm, &/or other forms of complexity across the (entire) incoming signal."

The signal traverses the tube the same as it would a circuit.

They both affect/change the sound/signal as a result.

Plus circuits are the basic building blocks of electronics. Hard to live without them.

What makes one categorically good and the other categorically bad?

Doesn't make sense.

That's why its funny.

Darn stereos and circuits, always mucking with the sound!
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