Tube Buffer vs Tube Pre-amplifiers?

[Verig]

If done correctly, adds nothing except addresses impedance mismatches (that are unlikely to exist in most systems with reasonably designed gear).

X-10D was released in 1996. There was perhaps a bit more actual use cases for it with all the stuff from seventies and eighties still in daily use.
X-10v3 came 2004. Never tried that one. I liked the old cylinder style more. It looked like it had to do something.

 

[MAB]

X-10D was released in 1996. There was perhaps a bit more actual use cases for it with all the stuff from seventies and eighties still in daily use.
X-10v3 came 2004. Never tried that one. I liked the old cylinder style more. It looked like it had to do something.

I never knew there was a newer version.
I did like the cylinder, it was so odd.

 

[Blumlein 88]

These are devices for musicians (electric guitar, electric bass, organ, etc.) not intended for use in a home hi-fi chain.

While true there is no reason you couldn't use them in a home system.

Basically tube sound is more of an amplifier thing. If not doing that might as well use plug ins.

 

[MattHooper]

My essentially know nothing “understanding“ has been that a mere tube buffer stage is where you are least likely to have audible tube colouration.

I admit, I sort of suckered myself into buying a peach tree audio integrated amplifier for another small system many years ago. It’s a solid state amp that makes a lot out of its tube buffer stage, with a single tube in a prominent window in the front panel. If you can see the tube glowing, it must have warm sound right? Subjectively I found zero difference between it and any other solid state amp. The tube is just for show and marketing. in fact, I prefer it didn’t have a tube as I see it as another possible failure point.

I also have a phono stage that has a tube buffer stage. I have no idea if in that case the tube is contributing anything sonically, but I didn’t buy it for that feature, but rather for the other convenient features it offered.

(Now, as for my old school CJ tube amps, you’ll be prying those out of my cold, dead hands…)

 

[EERecordist]

*** Please don't convert this thread into an attack on tube products ***
*** We know tube adds distortion, we have seen it in measurements ***

Those who are interested in Tube Products and have exposure to Tube Buffer and Tube Pre-amplifiers, please explain the differences and observations.

To start with - I have tried a few tube products, mostly sub-100$ tube pre-amplifiers you see on Amazon.
- They look nice when glowing, most of them have volume control with tone controls which essentially work
- I have not found them causing something to the sound that I could hear, but they did provide strong pre-amped signal

Now, someone tells me that I should try tube buffer which basically does not pre-amp the signal and rather do something else.
I have not found any speacific tube buffer being measured anywhere, and so asking here.

What do you know?
How a tube buffer is different?
Does it add or do anything better?
Do you have any recommendations?

Every gain stage adds noise. A preamp may have more than one gain stage. So I would say to start, minimize your tube gain stages.

A tube buffer is a preamp with no gain. It is not expensive to set up at home with an A-D and D-A converter and the free REW software to test preamps or buffers. You will not have the ultra-low distortion signal generator of the Audio Precision, but close enough for tubes. You can characterize harmonic distortion verses input level.

I would support the idea of using distortion plugins on a computer to experiment. Most plugins have a free 30 day trial. Each gain stage adds noise, so minimizing gain stages, the tube gain stages, is good for the signal.

Tube buffers, and tube preamps and amps, are small volume niche products. Hopefully the maker has an Audio Precision, and outgoing quality control measurements of noise and distortion. Or you could be a DIY maker just for curiosity.

Chinese tube gear makers should develop a faux tube amp for the looks, with the signal handled by a clean op amp / power gain. It would not be hard to build tubes with a super long-lived filament, or they could just put rejected tubes in the device.

 

[egellings]

*** Please don't convert this thread into an attack on tube products ***
*** We know tube adds distortion, we have seen it in measurements ***

Those who are interested in Tube Products and have exposure to Tube Buffer and Tube Pre-amplifiers, please explain the differences and observations.

To start with - I have tried a few tube products, mostly sub-100$ tube pre-amplifiers you see on Amazon.
- They look nice when glowing, most of them have volume control with tone controls which essentially work
- I have not found them causing something to the sound that I could hear, but they did provide strong pre-amped signal

Now, someone tells me that I should try tube buffer which basically does not pre-amp the signal and rather do something else.
I have not found any speacific tube buffer being measured anywhere, and so asking here.

What do you know?
How a tube buffer is different?
Does it add or do anything better?
Do you have any recommendations?

Tube gear can be designed with distortion that is well below audibility. Once that is achieved, there's really no need for better performance from an audibility point of view. Lower distortion than that would be for a purely acedemic pursuit. I agree that S.S. gear can be made with much lower, subaudible distortion than tube gear when you have the amount of open loop gain that transistor circuits and op amps have. The amount of corrective feedback can be very large with that.

My essentially know nothing “understanding“ has been that a mere tube buffer stage is where you are least likely to have audible tube colouration.

I admit, I sort of suckered myself into buying a peach tree audio integrated amplifier for another small system many years ago. It’s a solid state amp that makes a lot out of its tube buffer stage, with a single tube in a prominent window in the front panel. If you can see the tube glowing, it must have warm sound right? Subjectively I found zero difference between it and any other solid state amp. The tube is just for show and marketing. in fact, I prefer it didn’t have a tube as I see it as another possible failure point.

I also have a phono stage that has a tube buffer stage. I have no idea if in that case the tube is contributing anything sonically, but I didn’t buy it for that feature, but rather for the other convenient features it offered.

(Now, as for my old school CJ tube amps, you’ll be prying those out of my cold, dead hands…)

I wonder if the tube in that piece of gear is actually in-circuit, or if it is just a pilot light. If it's in-circuit, then it's likely just a cathode follower, which has a gain of a pinch less than one and
will only microscopically alter the sound quality.

 

[Waxx]

To answer the question, a tube preamp is a gain stage and a buffer (or it should at least be). A gainstage increase the voltage of the signal, a buffer is there to lower te impendance of the signal, but keep the voltage at unity (the same level as the input). The tube buffer is there to make the signal of the voltage stage fit for the next device, and is mostly a cathode follower layout, while the gainstage is taking it's output signal from the anode and provde voltage gain (increase of voltage). How this works electricly is a bit complex to post in an forum post but it's explained here: https://www.valvewizard.co.uk/

The colouring of a tube preamp comes mainly from the gainstage, even with tubes, a buffer should be fairly neutral in sound. Using a buffer seperate from a gainstage is only usefull if you use sources with a very high or wide range of output impendances (cfr, mainly old of very non-compliant esotheric stuff, not modern designs) or after a volume pot in a unity gain preamp. For colouring your sound a buffer is useless i think. I would even rather use an opamp as buffer for a trode tube as gainstage, that would make the tube preamp also colouring, but a lot cheaper and more stable in use.

 

[Peterinvan]

I asked ChatGPT to summarize...

• Function: Tube buffers are used primarily for impedance matching and sound enhancement without significant gain, while tube preamps amplify low-level signals and often provide additional control over the audio signal.
• Gain: Tube buffers provide minimal to no gain, whereas tube preamps provide significant gain to drive power amplifiers.
• Controls: Tube preamps typically offer volume and tone controls, while tube buffers usually do not.
• Application: Tube buffers are used to improve compatibility and sound quality in existing systems, while tube preamps are essential for amplifying low-level signals from sources like turntables.

Practical Use Cases​

• Tube Buffer: If you have a solid-state amplifier and want to add some tube warmth to the sound without changing the overall setup, a tube buffer can be a great addition.
• Tube Pre-amplifier: If you are building a high-fidelity audio system and need to amplify signals from multiple sources, especially low-output ones like turntables, a tube preamp is necessary.

Both tube buffers and tube pre-amplifiers have their place in high-quality audio systems, and the choice between them depends on your specific needs and the characteristics of your audio setup.



Factual?

 

[Waxx]

I asked ChatGPT to summarize...

• Function: Tube buffers are used primarily for impedance matching and sound enhancement without significant gain, while tube preamps amplify low-level signals and often provide additional control over the audio signal.
• Gain: Tube buffers provide minimal to no gain, whereas tube preamps provide significant gain to drive power amplifiers.
• Controls: Tube preamps typically offer volume and tone controls, while tube buffers usually do not.
• Application: Tube buffers are used to improve compatibility and sound quality in existing systems, while tube preamps are essential for amplifying low-level signals from sources like turntables.

Practical Use Cases​

• Tube Buffer: If you have a solid-state amplifier and want to add some tube warmth to the sound without changing the overall setup, a tube buffer can be a great addition.
• Tube Pre-amplifier: If you are building a high-fidelity audio system and need to amplify signals from multiple sources, especially low-output ones like turntables, a tube preamp is necessary.

Both tube buffers and tube pre-amplifiers have their place in high-quality audio systems, and the choice between them depends on your specific needs and the characteristics of your audio setup.



Factual?

I don't think so, a tube buffer will not colour the signal, and is a part of a tube preamp. Without the buffer the output inpendance of the gainstage is way to high for any power amp to receive the signal so it's absolute essential (or should be replaced with a transfo, that is less good). You can use a buffer seperate, but only for impendance correction, not as colouring or gainstage unit.

 

[Guddu]

Thanks everyone for chiming in.
I had different onion on tube buffer but seems like it may not even do anything if I try.
I have couple of products to try:
1) Schiit Vali - I did communicate with Schiit and they said it would act as buffer in stereo setup
2) new Aiyima tube pre-amp/buffer: Details suggest that it uses OPAMPs to pre-amp the signal with tone controls and tone defeat, while tube act as buffer but I haven’t tested myself yet

it’s just that I want to try again before I stop thinking about tubes for good or worse.

 

[mhardy6647]

Sorry, I can't recall the company that made them. But back in the 1990s I used a "starved tube" microphone preamp along into a Mackie mixer for recording. The starved tube preamp was a single space rack mount piece. It had the subjective effect of limiting peaks in a smooth and unobtrusive fashion. I used it all the time for my main pair of microphones, worked well.

I realize there have been myriad products that fit the description, but off the top of my head it sounds like (no pun intended) PAiA's "Tube Head" preamp.
Sold as a kit, there were two morphs: one for audiophiles shown below, and a rack mount version for folks who were workin' for a livin' with sound.

What do you guys think of the newly released Nobsound E6?

I think its great to see everyone with such an open mind here...... As far as "audiophile" tube amps striving for low distortion for the past 50yrs and now regressing, maybe thats because the "audiophile" tube amps with low distortion sound so much like their SS counterparts that people are...

www.audiosciencereview.com

 

[Robin L]

I realize there have been myriad products that fit the description, but off the top of my head it sounds like (no pun intended) PAiA's "Tube Head" preamp.
Sold as a kit, there were two morphs: one for audiophiles shown below, and a rack mount version for folks who were workin' for a livin' with sound.
View attachment 381632

What do you guys think of the newly released Nobsound E6?

I think its great to see everyone with such an open mind here...... As far as "audiophile" tube amps striving for low distortion for the past 50yrs and now regressing, maybe thats because the "audiophile" tube amps with low distortion sound so much like their SS counterparts that people are...

www.audiosciencereview.com

It was a different device. I'm pretty sure I read about it in one of the Home Recording magazines that were popular at the time, but can't recall the particular model save that it was from one of the better-known manufactures.

 

[SIY]

although there is a tendency for tubes to soft-clip when over-driven

Often stated, but not actually true. Tube amps are almost invariably RC coupled internally leading to blocking under overload. There's a very few amps out there which are transformer coupled internally, but that is not only stunningly expensive, it carries a bunch of new problems in.

quest is to see what a tube sound is as gazillion people say on internet.

There's an old saying that a million monkeys randomly hitting keys on typewriters for a million years will eventually produce the works of Shakespeare. The internet is proof that this is not actually true.

 

[majingotan]

Thanks everyone for chiming in.
I had different onion on tube buffer but seems like it may not even do anything if I try.
I have couple of products to try:
1) Schiit Vali - I did communicate with Schiit and they said it would act as buffer in stereo setup
2) new Aiyima tube pre-amp/buffer: Details suggest that it uses OPAMPs to pre-amp the signal with tone controls and tone defeat, while tube act as buffer but I haven’t tested myself yet

it’s just that I want to try again before I stop thinking about tubes for good or worse.

Schiit Vali has tube gain so it's a tube preamp and not a true buffer.

I have the Schiit Saga OG which is 100% a tube buffer circuit that I use as line attenuator for my headphone tube amp.

Review and Measurements of Schiit Saga Tube Pre-amp

This is a review and detailed measurements of the Schiit Saga passive/tube pre-amplifier. It is on kind loan from a member who has waiting literally months for his review! The Saga costs USD $349 from Schiit direct with stock tube plus shipping. The tube supplied with this unit was the...

www.audiosciencereview.com

I like glowing tubes and if you're pursuing a tube buffer for a sonic difference and not for glowing tubes, just get a tone control or digital EQ

 

[mhardy6647]

I like glowing tubes, too.
I like listening to their output as well.
Don't tell anybody.

 

[BentonF]

Found myself enjoying PAL and VHS and concentrating on it better than the usual HD the other day.

Are there any SET buffers with variable gain so you can adapt the level of gain to vary the level of distortion/glow/warmth/colouration?



.

 

[Zek]

Are there any SET buffers with variable gain

As far as I know, the buffer has no gain.
If it has variable gain, then it is a pre-amp.

 

[BentonF]

As far as I know, the buffer has no gain.
If it has variable gain, then it is a pre-amp.

Why does increasing the volume increase the volume whereas as the gain on electric guitar amp make it distort?

 

[Waxx]

Why does increasing the volume increase the volume whereas as the gain on electric guitar amp make it distort?

guitar amp tubes are driven very hard on high voltage (often against the limit of the tube). A pair of EL-34 tubes (One of the most popular tubes for guitar amps) in AB config, in a hifi amp gives 30 to 40w max, in a guitar amp 50w or even more. Also the preamp tubes are more often high gain so the power amp get's a very high input signal. In other words, the amps are dliberate calibrated to go into distortion in the high gain channels, while tube hifi amps are kept low gain, and so lower output for the same tubes and so have a much lower distortion.

The coloured speaker of a guitar amp also contribute a lot to that sound altough, Use a clean speaker with an analog tube guitar amp, and it will sound very bad distorted, but with the right speaker, it sounds like we love it. The gain that gives the distortion is in the preamp stage and the power amp stage, not in the buffer or the invertor stage if there is one (depending on the amp).

 

[mhardy6647]

While it is true that most if not all active preamps add gain*, the primary function of a volume control is attenuation.

_______________
* Technically, a "preamp" consisting of nothing more than a source selector, attenuator, and a buffer stage isn't an active preamp, I suppose -- even though it contains active electronic elements (tube, transistor and/or IC) and requires power to operate. We could be on the slippery slope between practicality and semantics.