What GE tubes specifically did you use for the preamp? Are those still the best one’s you’ve heard? I think I may give this thing a try since it’s so cheap.
The link to the Amazon page where I bought those tubes is in that post. I don’t know if they’re the “best” but there seems to be limited options for that tube type. These GE tubes are much better than the stock tubes.
Yeah all I know is the Voskhod sound better than the stock tubes. I said they sound “classier”, which might be a new one for audio descriptions, lol. But yeah, it means good mids and a ton of clarity, good soundstage. Stock tubes also sounded… muddy, or just lacking detail, compared to these.
So I own a Hagerman Tuba. But the Tuba lives in the bedroom (where I would use it more) and I wanted tubes in office. So I decided to give one of these tube buffers a try. The one I got was from FX Audio and it was about $30. The tubes were GE JAN 5654W and were $25 for the pair. I set up the tube preamp between my RME ADI-2 DAC and THX 789. Because the ADI-2 and 789 have two outputs and two inputs respectively, I could set it up so that I could instantaneously switch between having the tubes and not. I did the testing with my HD600 and here are my impressions:
- It didn’t make the 789 sound worse. At least as long as you didn’t turn preamp knob too far past 12 o’clock. It gets really distorted if you do.
- It brought up the lows up a bit and it relaxed the upper mids and highs some.
- It helped improve sound stage a little.
Overall the change in sound more subtle than I was expecting. But depending on the sound I’m looking for, it’s still an overall improvement. So I will continue to use it some of the time in my system.
If anyone else wants to get into tubes, I don’t really recommend this unless you’re on a super tight budget. I’m sure anyone new would want something more substantial. Although it is possible the other brands might be better than this one.
Update:
It turns out the extreme distortion at high volume was the result of the preamp clipping. This can mostly be remedied by reducing your DAC volume. This is worth doing because the tubes have greater effect at a higher volume setting. So in conclusion, I can recommend this particular setup more than before. But it’s still worth investing in a proper tube amp.
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Might be that the tubes haven’t burned in too – or you got bad tubes. Something like 50 to 100 hours of burn-in is recommended for tubes (literally “burn-in” this time: gets rid of unwanted stuff in the tubes).
With my Tube-03 my volume is set to max and there’s no distortion whatsoever. I got two pairs of (6J1P-EV) tubes, one starting to distort at 10 o’clock 
, and the one I use now, zero distortion.
Well that’s interesting. I did let them burn in but not for quite that long. Do you get a better tube sound if you max out the volume as opposed to having it half way?
Yes 
“volume” should be labeled “tubes +/-” really. It’s like “how much tubes do you want in your sound”.
Also, it’s chi-fi and tubes and these get hot, don’t leave it on at work at night. Fire hazard. 
(Like all tubes I’d say – whatever the price).
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I’ll try letting them burn in more. Although the particular tubes I have don’t get that hot. I can touch them without too much issue. Maybe I should have got different tubes? The GE tubes were well rated and recommended for this thing on amazon so I’d figured they’d be decent choice.
I can’t keep my fingers on mine after a few minutes. Maybe move em around in the socket and push em a bit to be sure they’re 100% well connected, too. Better connection might equal better sound.
I bought Voskhod 6J1P-EVs because someone on Amazon said they got impressive soundstage from em. Perfect for me because I got more bass (warmth), more smoothness (sounds “classy” lol) and still decent detail and “air” (10khz+).
Edit: 25$-ish for the pair too. I want to try GE tubes too… even if I’m pretty sure nothing will make it sound better than what I hear right now.
I let the tubes burn in longer, but that didn’t seem to make a difference.
So I went on Amazon and submitted a question to other users with the same preamp and tubes on whether they experienced significant distortion if go past around 1 o’clock. 2 people said they had the same problem while 1 said he has “'no problems with distortion cranked up.” He also suggested my amp could be clipping if the amp input voltage is greater than 2 V. So I decided to take some measurements my multi meter.
RME ADI-2 RCA Output at 0 dB: 3.3 V.
RME setting to get 3.3 V out of Preamp: -14.5 dB
RME setting for getting 2.05 V out or RCA: -4 dB
Tube Preamp outputs 3.3 V at about 10 o’clock
Preamp max output is about 6.7 V at around 3 o’clock
Preamp output voltage will start decreasing after going past 3 o’clock.
So in conclusion, it’s pretty clear that preamp is the one clipping for one reason or another. If I lower the volume of the ADI-2 enough, I can max out the preamp volume without getting major distortion. The “tubiness” of the sound also does appear to increase with preamp volume based on early tests
Oh, crap.
Well, yeah, that was one of the two possible problems. I did not knew the Tube-01 did this too. iWii reviews found this in the dac-tube-amp combo, but I think he sait 5 volts. 6.7 is… more than the double? 
I do not have this problem with my tube-03 either plugged straight into my AVR or my amp (and my multimeter isn’t here). Sorry anyway.
But… you can “lower the adi-2 preamp” and max the “tubiness” now? Sounds better?
Yes when I’m using the preamp, I will be lowering the DAC volume. Although I think I’m still getting a little distortion when maxing out the preamp volume. So I will keep it around 3 o’clock.
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Hope you enjoy it!
FYI I found out it makes… like, many times the difference with speakers versus headphones. For me anyway. My inexpensive speakers were a bit aggressive, and too bright for me at times. The tube buffer fixes this – also adding a ton of depth/width versus the “2D” soundstage I had before.
Odd. My little buffer does not have this issue either. But I think @LeDechaine and I both have models with tone controls. I wonder if that has something to do with it? Very well could be some QC issues too. One complaint I do have with my buffer is the tubes don’t sit very securely. They stay in place for the most part but a sizeable jolt to the desk or its shelf can unseat a tube and then there’s a lot of buzz.
Oh ouch, not for me. They’re hard to put in there. But it’s an easy fix, just move a few of the metal pins of the tubes like one millimeter (…and don’t break em lol) and the tubes will fit more securely in place.
Yes, to get too much volume/distortion with this amp (tube-03 or tube-03 clones), you probably have to put bass + treble + volume to the max heh.
I don’t think it’s a QC issue since two people responded saying they had the same issue. But I suppose people with the problem might be more likely to respond. So who knows.
Also this made me laugh:
I don’t think he’s very satisfied with his tube preamp lol
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It’s a weird issue because… tubes. You never know if the tubes are the problem or the amp. But if it pushes 7 volts I’m guessing it will push 7 volts all the time, whatever the tubes?
I got four 6J1P-EV tubes. Two start distorting at 10 o’clock on my Tube-03. Two don’t distort at all with the volume at 100%…
Do you have the cheap-ass chinese stock tubes they came with? They’re essentially worthless but, maybe just put these in, see if the voltage is different with the volume at max (I don’t know lol), but above all, you can hear if it distorts at max volume with these tubes too – maybe it depends on the tubes.
I was experimenting on cheap tube buffers for a while now, and my conclusion is that they generally aren’t worth it, even if you have good tubes. The sound changes aren’t enough.
I think in the end, it’s worth it to get either a proper OTL or (more likely since you want the power of a solid state) a hybrid like the TA-10/20. The effect of tubes is so much more than tube pre for some reason, and because it’s hybrid, it can run planar.
My favourite setup at the moment is running the Argons off the TA-20, using 1951 RCA black tops. It’s got a much more power single ended than the 789 at 50ohms, and the effect with the tubes is amazing.
Personally, it was just the best for my speakers that needed just a little bit more warmth. Or, ironically, for my SMSL Sap-1 (inexpensive Class A headphone amp with lackluster 10khz+ highs), because this inexpensive tube buffer also extends the highs.
More than enough for me to make me go “wow” because I never heard that much soundstage and depth from my speakers. A bit weird with headphones sometimes, but this little thing sure made me smile.
But I understand, if you really want an enormous difference, yes, go for big-ass transformers and big-ass tubes.
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Ah ok, as far as I understand tube pre’s work better with speakers than they do with headphones. They did after all exist as a market long before people were putting them before headphone amps. Someone told me once it’s about the impedance of the amps.
But I was talking from my experience with headphone amps and tube pre’s.