To my ears, I prefer my own "hybrid"
I like a Tube Pre on a SS amp.
DIY 6SN7 Aikido -> DIY Krell KSA50 Clone -> Magnepan Tympani IVa = best of both Tube/SS worlds IMO...
Best preamp I ever heard on my amp/speakers is a BAT VK-3ix (tubed pre) - absolute magic...some day I'll get my BAT, until then I am quite happy with my Aikido.
OT - Please, don't flame me over my inefficient energy wasting Class A amp either....
I like a Tube Pre on a SS amp.
DIY 6SN7 Aikido -> DIY Krell KSA50 Clone -> Magnepan Tympani IVa = best of both Tube/SS worlds IMO...
Best preamp I ever heard on my amp/speakers is a BAT VK-3ix (tubed pre) - absolute magic...some day I'll get my BAT, until then I am quite happy with my Aikido.
OT - Please, don't flame me over my inefficient energy wasting Class A amp either....
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Ah, ok.
But most don't even think of transformers for voltage gain so I think it was fair to bring that into the discussion.
se
Voltage gain does not mean energy gain. Transformer is a passive component till the time perpetuum mobile would be invented (mag amp is another story).
It does not matter how many passive components and where have been placed in the signal path amplification stages are mandatory either SS or valve in order to make sound come out of the loudspeakers.
Actually every passive component decrease signal energy and distort it.
Moreover analog signal amplification topology achieved its maturity 5 or 6 decades ago. Neither well equipped engineers with anechoic chambers and expensive spectrum analyzers no diy-crowd could invent something really new nowadays.
Some sources would not have enough gain, and you would be stuck again with the problem of long speaker cables. Monoblocks and a preamp that can drive long cables without degradation solves that issue, one that is quite audible BTW.
That's not really true. Before I came along no-one was using the Circlotron, and now it has become the most common output circuit found in OTLs, making OTLs a lot more practical and reliable than they were before.
So far in the US it seems I am the only one using them in preamps, *with* fully differential circuitry, something that existed 50 years ago, but was not something you saw in audio, again until I came along to put them there.
I've seen enough creativity in the DIY community in the meantime that the idea that nothing new can be done (something they said to me in school back in the early 80s, FWIW...) is absurd. Don't look at breakthroughs, look at the evolution.
Ralph, what does a Circlotron get you in a preamp that only swings a few volts? Conventional circuits seem to be pretty adequate for the job.
Perhaps. But that of course would depend on how much gain the amplifier has and how much power your speakers require.
But more often than not, a separate preamp/amp combination results in a hell of a lot of excess gain.
Your average preamp usually has about 20dB of gain and power amps around 26dB.
Most amps don't require more than a volt or two for full rated power and most sources have full scale outputs of around a volt or so. So 20dB of gain is far more than is needed in the vast majority of cases.
I haven't found that to be a problem depending on how you're defining "long."
Why should a preamp somehow be more capable of driving long cables without degradation than a power amp? What's special about a preamp in this regard compared to a power amp?
Certainly from a financial point of view it would be advantageous to be able to sell someone three boxes instead of one, but I can't say I see any particular technical advantage.
se
Current. The signal current from a pre is so low that the frequency response is generally not altered with a long cable run (assuming a reasonably comptent preamp and nonpathological cables). As you know, with longer speaker cables, you can get frequency response errors.
Aw, c'mon Steve, you know Ohm's Law. I think you were in enough cable discussions to know how a speaker cable can alter frequency response, and not just "low pass." A preamp-to-power amp interconnect? Not so much.
I can't see what the length of the speaker cables has to do with a pre-amp. Am I missing something? 
regards
regards
Yes, I know Ohm's Law. But I don't know how a cable effects frequency response depending on how much current is flowing through it.
All else being equal, what's the difference if you're dealing with a few amps of current or a few milliamps?
Yes. But I don't recall anyone claiming it was because of "current."
se
I can't see what the length of the speaker cables has to do with a pre-amp. Am I missing something?
Simple. It's "current." What, are you stupid or something? 😀
se
I can't see what the length of the speaker cables has to do with a pre-amp. Am I missing something?
Greg, I think the underlying meaning was that if the power amps are at the speakers (and fed from a central pre amp) then the speaker cables are short, whereas if a power amp sits central (alongside the preamp), or is an integrated amp, then the speaker cables are long.
The ability of the preamp to control the interconnect is the issue here. Please go back to earlier points in this thread- I covered this issue before.
What the Circlotron gets you is a simple circuit that allows balanced direct-coupling to the output, in a way that allows for current so you can control the cable. This means no big coupling cap- if you use coupling caps at the input of the Circlotron you can keep them rather small and they will not do any harm.
Getting rid of the output coupling cap is a big deal in a tube preamp. Most tube preamps have very large coupling caps so that they will make bass into a transistor amp. The very size of the cap causes coloration and imparts a 'slowness' to the sound that many people think is an inherent 'tubey' coloration. Its not- its the cap.
What the Circlotron gets you is a simple circuit that allows balanced direct-coupling to the output, in a way that allows for current so you can control the cable. This means no big coupling cap- if you use coupling caps at the input of the Circlotron you can keep them rather small and they will not do any harm.
Getting rid of the output coupling cap is a big deal in a tube preamp. Most tube preamps have very large coupling caps so that they will make bass into a transistor amp. The very size of the cap causes coloration and imparts a 'slowness' to the sound that many people think is an inherent 'tubey' coloration. Its not- its the cap.
That's interesting; I've heard other people say that. Is it factual or your opinion? I mean, are there some figures and / or references that you could point me to so I could have a read?
Thank you.
I went through all of your posts in this thread and pretty much about all you said about the ability of a preamp to "control" the interconnect is that the preamp has to have a low output impedance.
Well, power amps have low output impedances as well. Typically lower than the output impedance of many preamps.
So again, what exactly makes a preamp somehow more capable of driving long cables than a power amp?
se
I cannot agree more. There are some very expensive large coupling caps in my collection which i just cannot use. About 1uF is the largest value which works well, even if it's a bit limiting with respect to the input impedance of the power amp.
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