Thoughts on tubed preamps?

[ahofer]

[Never mind, I see that references were provided above and Noobie hasn't returned to dispute those. But this was my immediate reaction]

Regarding evidence that blind testing is preferable/useful: My presumption of good faith is being sorely tested here.

https://www.aes.org/e-lib/online/browse.cfm?elib=6338
https://www.aes.org/e-lib/browse.cfm?elib=5549
https://asa.scitation.org/doi/abs/10.1121/1.1917190

Ask yourself why blind tests are the AES protocol (as they are here, for instance - https://secure.aes.org/forum/pubs/conventions/?ID=4160)

One might well reverse the question - do you think sighted bias exists (lord knows there's plenty of evidence of that, and it was conceded above)? If it does, what method do you suggest for controlling for it? how else would you determine whether an observation is strictly audible as opposed to suggested/invented?

 

[egellings]

I periodically measure the home made preamp's clean looking voltage swing, noise, F.R. and distortion. Deviations are small, less than I am likely to be able to tell by listening. Unless the performance really goes south, I likely would not hear it. There's also the dirty eyeglass lens effect happening. My glasses slowly get soiled as the day wears on and I don't notice it much, and when I clean them I notice the big improvement. As the tubes age, the performance, if it degrades, does so in such a gradual way that I don't notice it happening. I keep a fresh reference set of tubes for the preamp, and will once in a blue moon try them to see if I notice a difference beyond that caused by placebo effect. If there's a noticeable improvement with the changeout, I order a new set of tubes and keep the 'reference' set for later tests. In 8 years, I could not justify replacing tubes based on this test result.

 

[MattHooper]

Aaaagh!

I'm kicking myself!

I just returned my pal's Bryston amp and I forgot: I wanted to try a very basic, crude experiment of recording the sound from the speakers with each amp playing - Bryston vs CJ tube amps - to see if I could tell the recorded sound files apart, without knowing which was which. (I don't have a voltmeter handy, but figured I could level match if need be in Pro Tools). Dammit!

 

[egellings]

Shoot! It be that way sometime.

 

[billmr]

Similar effect on horns (sax, trumpet) as on guitars, in my experience. It can be a pleasurable effect.

But on piano...meh...

I just got spammed from someone who thinks I should buy Rogue Audio Preamp, and I was curious if one of these had ever been measured.

I have had several tube amps over the years, and I especially liked them on cold winter nights, The plasma tv helped too.

Both sounded and looked good.

 

[beefkabob]

I just got spammed from someone who thinks I should buy Rogue Audio Preamp, and I was curious if one of these had ever been measured.

I have had several tube amps over the years, and I especially liked them on cold winter nights, The plasma tv helped too.

Both sounded and looked good.

I've listened to one of their power amps. It was so distorted, i couldn't make out the song's words.

 

[JuliaCoder]

Voltage gain is where tubes are reputed to sound better. Preamps have little or none of that. So, I'd expect to see tubes in the pre-output stage of speaker amps and in headphone amps for 600 ohm headphones. But those are hard to find. It seems the only thing that matters is having tubes somewhere.

 

[MakeMineVinyl]

Voltage gain is where tubes are reputed to sound better. Preamps have little or none of that. So, I'd expect to see tubes in the pre-output stage of speaker amps and in headphone amps for 600 ohm headphones. But those are hard to find. It seems the only thing that matters is having tubes somewhere.

Voltage gain is what a preamp does. It is all about voltage gain.

 

[dougi]

I just got spammed from someone who thinks I should buy Rogue Audio Preamp, and I was curious if one of these had ever been measured.

I have had several tube amps over the years, and I especially liked them on cold winter nights, The plasma tv helped too.

Both sounded and looked good.

Stereophile have good measurements on a couple of different Rogue preamp models.

 

[egellings]

Boy, if an amp doesn't know the words, then we have a problem.

 

[mhardy6647]

Boy, if an amp doesn't know the words, then we have a problem.

Suitable for karaoke use only.

 

[beefkabob]

I am not kidding. I listened to several songs, and it was like every singer had been replaced with Biz Markie.

 

[Bob from Florida]

Since power amps are typically driven to full output power with a volt or maybe two volt input signal amplitude, I don't see where the added voltage swing of a tube preamp is any advantage, since a SS preamp with 15 volt rails can easily provide enough drive to get max output out of the power amp. It's no big deal.

One place it can make a difference is headroom in a phono pre-amp. A well designed moving magnet tube phono pre-amp can have greater headroom and handle pops and clicks better. Solid state with that kind of headroom is harder to come by. Now if only interested in line level sources then a good tube or solid state line stage should be fine. Cheap ebay tube pre-amps with 12 volt plate supplies are bogus.

 

[NeonHD]

How basic and how far back do you want to go? DBT as a necessary control in any sensory experiment has been known for over a century and is discussed thoroughly in literally any introductory text on sensory science or experimental psychology. And just about any other experimental science like pharmacology, epidemiology, medicine, biology...

Audio people became more aware of it with publications like Munson and Gardner, JASA Volume 22, 675; 1950; Lipshitz JAES Volume 29 Issue 7/8, 482; 1981; Clark JAES Volume 30 Issue 5, 330; 1982; Lipshitz 8th International Conference: The Sound of Audio (May 1990); but the necessity of DBT as a basic control is subsumed under basic experimental design and pre-dates all of these references.

It's not that it's "better," it's that it's absolutely necessary for validity. It is the most basic of all controls.

Sorry for the necropost, but I had to make an account just so I can like this post. Couldn't have said it better. I'm a psychology major and can confirm that in order for ANY scientific measurement regarding the senses to be valid, double-blind testing is needed. This is to mitigate the effects of observer bias. It's literally a fundamental part of experimental research and design. People who are skeptical against such fundamental principles might as well argue against the scientific method while they're at it.

 

[loudnoise]

There's no doubt that tube amps are the best sounding. But there are some great solid-state amps too.
I personally like solid-state amps over modeling amplifiers.

 

[SIY]

There's no doubt that tube amps are the best sounding.

Uh huh.

 

[Gorgonzola]

Just gotta get my 2 cents worth in here.

I've never owned or used a tube power amp. I have used three different tube preamps over the years, several solid state, and a couple of passives. I don't have a categorical conclusion about which is "better".

I have my impressions about the sound of each -- I don't feel the need to prove these to others or, FTM, to myself. You may find them useful or not; (it's easy to spot the people who will dismiss them out of hand).

Simply put, I believe the passives are the "cleanest" and effect the least changes to the source recording. However, (in my subjective experience), passives sometime reduce dynamics but it depends on the up- and downstream components.

I have no general conclusion about s/s preamps. They are very similar to each other, (seems to me). At one point I had an AV processor that permitted DSP to be by-passed and using that, I concluded it was significantly less "clean" that s/s preamps and the tube preamp I'd used around the same time.

I've used three different tube preamps in the fairly recent past. Differences were "not subtle", to employ a subjectivist audiophile phrase. First and worst was a Glassware Aikido: very great loss of "air", dynamics, and detail. Second and much better was the Schiit Freya +: much less loss of the aforementioned qualities. Third and best is my Sonic Frontiers Line 1 SE+: this almost equals the passives in terms of detail and dynamics but add just a taste of warmth, body, and subtle dimensionality.

SLY makes the point that well designed tube and solid state sound the same; the Sonic Frontiers come close to proving, (i.e. demonstrating), that to me.

I should say the tube rolling made a subtle difference in case of the Sonic Frontiers. Currently I'm using vintage Amperex 'PQ' USA white labels at the gain stage. They give the most "body" to the sound but I have decided whether I like as much of that as I'm hearing -- clearly it is an addition to the source sound, not a fully accurate reproduction. With the Reflector 6H23P-EB/6922 tubes, the SF sounds quite close indeed to passives.

 

[Frank Dernie]

I should say the tube rolling made a subtle difference in case of the Sonic Frontiers. Currently I'm using vintage Amperex 'PQ' USA white labels at the gain stage. They give the most "body" to the sound but I have decided whether I like as much of that as I'm hearing -- clearly it is an addition to the source sound, not a fully accurate reproduction. With the Reflector 6H23P-EB/6922 tubes, the SF sounds quite close indeed to passives.

The whole concept of tube rolling in hifi amps seems bizarre to me.
I completely understand in guitar amps where the valves were being run away from their linear region and different valves had different transfer functions in overload so sounded different.

In a hifi amp the valves will be being used in their linear range so unless one is faulty any change in SQ is more likely to be imagined than real.

I suppose it is a bit of fun for equipment enthusiasts who aren't big into music listening.

 

[Gorgonzola]

The whole concept of tube rolling in hifi amps seems bizarre to me.
I completely understand in guitar amps where the valves were being run away from their linear region and different valves had different transfer functions in overload so sounded different.

In a hifi amp the valves will be being used in their linear range so unless one is faulty any change in SQ is more likely to be imagined than real.

I suppose it is a bit of fun for equipment enthusiasts who aren't big into music listening.

Well I think the fun part is often overlooked. At the same time it's not fair to imply that music listening and equipment appreciation are mutually exclusive.

As for tube rolling in the hi-fi case, differences are very subtle and might well be imagined in many case, (same for op amp rolling only more so).

 

[Bob from Florida]

Well I think the fun part is often overlooked. At the same time it's not fair to imply that music listening and equipment appreciation are mutually exclusive.

As for tube rolling in the hi-fi case, differences are very subtle and might well be imagined in many case, (same for op amp rolling only more so).

A lot of folks tube roll different model tubes - comparable from a pin out perspective. This will change the sound usually because the circuit is no longer correct and you are hearing distortion not there before. The only sub I used to use in a Phono stage was 12BZ7 for a 12AX7 that worked reasonably well. Guitar amps are all about distortion so subs can be quite good there.