Some interesting reads

[E-Stat]

Ajani suggested this and RGA was just praising Grant Fidelity. I do not have much money right now to spend on upgrades and not sure what I want. I see Grant Fidelity has a store on E-bay and has a special on what looks to be similar, their B-283 Tube Processor regularly $219 for $150.

Don't get me wrong. I use tubes in the required gain stages in both my music systems. Triodes running class A are excellent output devices. On the other hand, I cannot imagine how any additional and otherwise superfluous stage can *fix* the sins of that which precedes it. A perfect gain stage can only render the circuit unchanged. Any *correction* itself would necessarily be added distortion. My suggestion would be to improve the quality of the building blocks, not add band aids.

rw

[Feanor]

Don't get me wrong. I use tubes in the required gain stages in both my music systems. Triodes running class A are excellent output devices. On the other hand, I cannot imagine how any additional and otherwise superfluous stage can *fix* the sins of that which precedes it. A perfect gain stage can only render the circuit unchanged. Any *correction* itself would necessarily be added distortion. My suggestion would be to improve the quality of the building blocks, not add band aids.

rw

'Stat, you answered the question. The tube 'buffers" do what tubes do in general: they add low-order harmonic distortion to the signal. This type of distortion has been proven to sound pleasant. It adds the things tubes are praised for: warmth, body, harmonic richness, depth, an "organic" quality -- or the semblance of these things. Also, where relevant, tubes' low order distortion masks the unpleasant, high order distortion present in s/s amps that use a lot of negative feedback. I strongly suspect they this distortion works to mask certain nasty digital effects such as jitter.

Thus a significant portion of the tube advantage can be obtained inserting a simple tube circuit basically any where in the signal path, even if that tube circuit is just unity gain buffer. I have explained all this before but people don't listen. (Let me remind everyone that I'm a tube user myself.)

[E-Stat]

Also, where relevant, tubes' low order distortion masks the unpleasant, high order distortion present in s/s amps that use a lot of negative feedback... I have explained all this before but people don't listen. (Let me remind everyone that I'm a tube user myself.)

So how does the "good" distortion mask the bad distortion? Especially given the fact that the magnitudes of distortion for line stages are typically in the 0.01-0.03% range if not lower. Unless of course this buffer design, unlike any line stage, has added deliberately high levels of distortion to achieve this effect. The theory would also suggest that this masking effect would hide the *real" distortion profile of sources upstream of the tubes. A Toshiba 3950 still sounds harder and less dimensional than a GamuT CD-1 through those VTL amps. I hear significant differences in apparent hardness of various CDs through the Manley Sigma Delta DAC / linestage.

If you recall, I have an Audio Research preamp, but use it solely for vinyl. Since the GamuT has sufficient drive to power the amps directly and bypass the unit altogether, I can truly compare what it does to the signal. What I find is that is that the preamp shrinks the image width (likely due to the volume/balance control as its measured separation is relatively poor) and reduces resolution as I find every gain stage does to an extent. The theory would suggest that things would be better, not worse, with the unit in the path.

It adds the things tubes are praised for: warmth, body, harmonic richness, depth, an "organic" quality

Or choice "B", preserves such qualities when they are present in the recording. I have numerous examples of CDs and vinyl alike in my collection that do NOT exhibit those desirable traits when run through either music system containing tube components. The Best of the Hollies, for example, has always sounded thin, flat, one-dimensional and a bit hard regardless of the system on which I play it. I listen to it solely for sentimental reasons as it brings back pleasant memories from my childhood. Unfortunately, this is just one example of the "bad-stuff-sounds-worse-on-good-gear" phenomenon. I forgot exactly what piece it was, but something I brought to Sea Cliff once sounded almost unlistenable with its sins laid bare on the spectacular all tube system there.

I don't find that any really good tube gear can turn a sow's ear into a silk purse.

rw

[Feanor]

So how does the "good" distortion mask the bad distortion? Especially given the fact that the magnitudes of distortion for line stages are typically in the 0.01-0.03% range if not lower. Unless of course this buffer design, unlike any line stage, has added deliberately high levels of distortion to achieve this effect. The theory would also suggest that this masking effect would hide the *real" distortion profile of sources upstream of the tubes. ...

But I think this masking does occur. People do report the "warmth, body, harmonic richness, depth, an 'organic' quality" resulting from the insertion of a simple, unity gain tube buffers. And I can reported based on my use of a tube preamp versus the passive preamp I used before.

...
I don't find that any really good tube gear can turn a sow's ear into a silk purse.
...

Of course I agree with this.

[E-Stat]

But I think this masking does occur. People do report the "warmth, body, harmonic richness, depth, an 'organic' quality" resulting from the insertion of a simple, unity gain tube buffers.

Maybe they truly needed an impedance buffer! Here's one case where the addition of a tube buffer stage was superfluous: Musical Fidelity DAC Another unit tested added some gain and admittedly helps some CDPs with weak op amp output stages: X-10D.

And I can reported based on my use of a tube preamp versus the passive preamp I used before.

"Warmth" can always be achieved via altered frequency response. Perhaps your SF is like older C-J units having a slightly chocolate flavor to their tonal balance. The MKII version of my preamp sounds leaner, but the output devices are unchanged.

rw

[Ajani]

Maybe they truly needed an impedance buffer! Here's one case where the addition of a tube buffer stage was superfluous: Musical Fidelity DAC Another unit tested added some gain and admittedly helps some CDPs with weak op amp output stages: X-10D.


"Warmth" can always be achieved via altered frequency response. Perhaps your SF is like older C-J units having a slightly chocolate flavor to their tonal balance. The MKII version of my preamp sounds leaner, but the output devices are unchanged.

rw

I think this line in your second link best sums up the use of tube buffers:

With both these units, it will be very hard to predict whether or not they will work an improvement on the sound of any specific system.
.................................................. ..............
But more than usual, you should try to audition these units in your own system before you make a purchase decision.

But in fairness to the buffers, that quote is true of all audio products... Will a Passive Pre sound better than an Active? Will no Pre sound better than either Passive or Active? Will a Turntable sound better than a CD player? Will Tube sound better than Solid State? At the end of the day, you just have to try it for yourself to see if it works for you...

[E-Stat]

Will no Pre sound better than either Passive or Active? Will a Turntable sound better than a CD player? Will Tube sound better than Solid State? At the end of the day, you just have to try it for yourself to see if it works for you...

I certainly agree about system matching considerations. Passive arrangements are highly sensitive to specific gain and impedance matching issues. Similarly, tube power amplifiers are not a good match for all speakers. Where my VTLs are wonderful with the stats, they are not so much with the Advents where a "lesser" Threshold sounds better.

I do not, however, believe that all tube gear make music better by "masking distortion". My experience suggests it has to do with the nature of their distortion spectra which is shared by a few SS designs as well.

rw

[Feanor]

...
"Warmth" can always be achieved via altered frequency response. Perhaps your SF is like older C-J units having a slightly chocolate flavor to their tonal balance. The MKII version of my preamp sounds leaner, but the output devices are unchanged.

rw

In fact the Sonic Frontiers are somewhat (in)famous for a solid state-like sound and are not archtypically tubey. Using the standard Sovtek tubes my SF sound remarkably like the Adcom GFP 750 I'd been using in passive mode.

I wanted a bit more of the tube sound but got a measure of it only after some tube rolling. My best result was with Amperex white label 'PQ' tubes.