Everyone who has bought the kit has tried that. It comes with Chinese 6N3P tube.
We have to use the kit's potentiometer dialed down to remove about 50% of the input voltage if you didn't want about 50% distortion.
Therefore, it is probable that somewhere in the kit circuit is insufficient voltage.
Yes, that is certainly true!
Line level is too much for it. Computer is too much for it. Tuner is too much for it. Mp3 player is too much for it. CD player is too much for it. TV is too much for it.
Fortunately the kit comes with a potentiometer to decrease all of these. Unfortunately, the consequence is that the output of the buffer is very quiet and may require a preamp after the buffer for make-up gain.
Problem: Needing to add a preamp because of the buffer.
Whoa...
There is a lot of fuzzy questions and fuzzy answers in this thread!
The buffer (yes, as someone stated above, there is no gain, hence it is a 1x buffer) psu gives +/- 30Volts and that is 60V over the tube, fairly good but does not give room for the ultimate dynamics, do NOT use a 15 or 18VAC supply with the original components, the capacitors might pop.
The 7805 filament regulator gets really hot with 6N3, the filament voltage is too low with only one 1N400x diode, use two or better three diodes in series, or replace with a 7806 reg. with one diode.
The sound is surprisingly good when the filament is not starved and you have done all soldering correctly, considering this being a $20 kit from china...try to buy the same parts in the US for $20...
I use a 2C51 tube and is quite satisfied with the sound.
I've also read that some people find the sound very good............maybe use another power supply........
Paging the tube experts. Can we do a preamp?
The tone is lovely, the resolution poor, the input voltage very limited, and a kit in stock condition is workable as a guitar effect.
This very accessible an inexpensive tube buffer, alas, still awaits input/repair/redesign by a tube expert. It seems that this could be a great beginner project for a useful 6N3P preamp, since buying the highly available Russian replacement tube (6N3P-EV), two electrolytic caps (100v) to facilitate higher voltage use, a 6v reg (OnSemi MC7806BT) for heater, and different resistor values (TBD) is still yet an accessible price point for such a project.
Fixes?
Usefulness: Transform it into a preamp for computer/digiplayer/iphone, very much a competitor to the MooseFet preamp and for the same task?
Resolution: Find the willing tube expert thereby also finding the correct component values for redeployment as a well performing preamp?
The tone is lovely, the resolution poor, the input voltage very limited, and a kit in stock condition is workable as a guitar effect.
This very accessible an inexpensive tube buffer, alas, still awaits input/repair/redesign by a tube expert. It seems that this could be a great beginner project for a useful 6N3P preamp, since buying the highly available Russian replacement tube (6N3P-EV), two electrolytic caps (100v) to facilitate higher voltage use, a 6v reg (OnSemi MC7806BT) for heater, and different resistor values (TBD) is still yet an accessible price point for such a project.
Fixes?
Usefulness: Transform it into a preamp for computer/digiplayer/iphone, very much a competitor to the MooseFet preamp and for the same task?
Resolution: Find the willing tube expert thereby also finding the correct component values for redeployment as a well performing preamp?
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This tube?
VINTAGE USSR Russian Tubes 6N3P-E/ECC42/6385 2pcs.1972 year | eBay
Is this the right/preferred upgrade tube?
VINTAGE USSR Russian Tubes 6N3P-E/ECC42/6385 2pcs.1972 year | eBay
Is this the right/preferred upgrade tube?
Those 6n3p-E should be decent
With Soviet 6n3p the safest bet is to go for -EV version (though the 'V' part may have not existed in 1972; there is also -ER but priced higher because of gold grids)
These are slightly more expensive and sound almost the same (perhaps a bit brighter, in my amp) than 6N3P-EV but look much nicer
5670 W 2C51 New JAN G.E. Tube eq. Western Electric 396A | eBay
I've had a pair playing in my amp for 6 years now and no signs of getting tired.
Thanks.
I have some of those G.E 5670 and also some Tung Sol 2C51, but these all go very dull on this particular circuit (albeit the Tung Sol is much higher resolution). So, proceeding cautiously on the tube upgrade since it is becoming a lot like throwing good money after bad (as usual for tubes?). Perhaps this circuit board needs different resistor values or something, but I'm not a tube expert, and therefore stuck. Theoretically, there's a fellow in the tube forum who knows how to adapt this circuit for optimal preamp performance with the 6n3p. And, there has been a long, long wait. . .
I guess 5.7V is too low for filament power supply (starving filament). Place an extra 1n4001 because it must be 6.3V +/-5%. This could be your clipping problem Daniel.
Otherwise 24Veff instead of 12Veff would be an option too as input power but find some fix for the filament regulator. Build a voltage quadrupler for two times 60V. Check ripple with scope after the two transistors........
Otherwise 24Veff instead of 12Veff would be an option too as input power but find some fix for the filament regulator. Build a voltage quadrupler for two times 60V. Check ripple with scope after the two transistors........
Thank you!
I used a 6v reg already and that didn't help. It seems possible to decipher the voltage part if I could have your recommendation as to transformer voltage? It looks like, I guess, a 14+14 transformer? Or should I use an 18+18 transformer? I do have some 100v capacitors available to replace some of the 50v caps.
On voltage boost, there was a previous post about putting a resistor in instead of one of the transistors (that limit voltage unnecessarily) and they never said which one and I don't have any 3 pin resistors that could directly replace one of the transistors even if I knew which one to replace?. . . so that bit may could withstand some deciphering? Help, I probably need to turn off the parking brake?
I am still a bit amazed that a weak computer sound card could cause a buffer to clip. However I do think that the device would be more nicely (re)employed as a preamp since a buffer only hopes to be as good as a wire and isn't so a preamp might make more sense than that.
P.S.
I have 6N3P-DR in the mail.
Thank you for this clue. I think that I needed the slightly brighter, since none of the other tubes I tried were as bright as the chinese 6n3p. Going forward, I'm hoping to keep the pretty tone, but somehow install some clarity/resolution and double the headroom. I've no idea how, but any change in generally the right direction would be nice.
P.S.
Since there's multiple boards available, I wonder about re-wiring for buffer+preamp or something like that. Options?
Hello Daniel,
If I recall correctly your new cat pressed the purchase key on your keyboard. I have two equally amusing cats.
I think you should call that purchase a sunk cost or an “Oh Poop” learning experience. If it clips on less than 2 volts input it is junk. To follow the buffer with a preamp defeats the entire purpose of the low impedance output buffer in the first place.
If you want a tube buffer in a kit, try out the Aikido Cathode Follower by tubecad.com . I believe there is an all in one version with power supply minus the transformer.
All for Fun
DT
If I recall correctly your new cat pressed the purchase key on your keyboard. I have two equally amusing cats.
I think you should call that purchase a sunk cost or an “Oh Poop” learning experience. If it clips on less than 2 volts input it is junk. To follow the buffer with a preamp defeats the entire purpose of the low impedance output buffer in the first place.
If you want a tube buffer in a kit, try out the Aikido Cathode Follower by tubecad.com . I believe there is an all in one version with power supply minus the transformer.
All for Fun
DT
Re-Purpose?
Well, they does offer power, a tube and a tube socket. I'm assuming that resistor values can be changed or the boards re-purposed. I have so far 6N3P-DR and a Tung Sol 2C51 tubes to explore. Despite the fact I know absolutely nothing about tubes, it is visually simple since the amount of connections is very small. I guess I just need to find example circuits for these tubes and try the options for discovery. Any suggestions for these particular tubes?
Well, they does offer power, a tube and a tube socket. I'm assuming that resistor values can be changed or the boards re-purposed. I have so far 6N3P-DR and a Tung Sol 2C51 tubes to explore. Despite the fact I know absolutely nothing about tubes, it is visually simple since the amount of connections is very small. I guess I just need to find example circuits for these tubes and try the options for discovery. Any suggestions for these particular tubes?
6n3p Russian. . . much higher resolution.
That 6n3p Russian tube is clear (unlike the chinese tube) and the frequency response is fairly neutral (which is the same as before). It is a partial success. But there are two remaining questions:
Vague Clues to sort (halp!!!):
1). How much to ". . .Increase the 470R to Cathode. . ." for less clipping? Increase the value or decrease the value to increase the current or what exactly to do???
2). Which transistor(s) to replace with a resistor and how (to remove extra voltage limiting so I can use higher voltage transformer)?
(in regards to this circuit <<< link)
That 6n3p Russian tube is clear (unlike the chinese tube) and the frequency response is fairly neutral (which is the same as before). It is a partial success. But there are two remaining questions:
Vague Clues to sort (halp!!!):
1). How much to ". . .Increase the 470R to Cathode. . ." for less clipping? Increase the value or decrease the value to increase the current or what exactly to do???
2). Which transistor(s) to replace with a resistor and how (to remove extra voltage limiting so I can use higher voltage transformer)?
(in regards to this circuit <<< link)
I built two of these:
The first one I replaced the caps in the power supply (8 + 1 + 1) with better quality caps, changed out the five volt regulator for a six volt one, and put a resistor in line with the led that illuminates the tube to dim it.
For the second one I lifted all the audio components off the board and reassembled them on a small piece of perf board to use as an input stage for a chip amp. I powered this one with a clean +/- 18 volt power supply from the LM3886 amp that it is now part of. I lit the tube with a 6.3 volt filament transformer.
In both cases the units work well, exhibiting roughly unity gain. Clipping, at least to my ears, has not been a problem and the sound quality changes are pretty much as expected.
Best,
John
The first one I replaced the caps in the power supply (8 + 1 + 1) with better quality caps, changed out the five volt regulator for a six volt one, and put a resistor in line with the led that illuminates the tube to dim it.
For the second one I lifted all the audio components off the board and reassembled them on a small piece of perf board to use as an input stage for a chip amp. I powered this one with a clean +/- 18 volt power supply from the LM3886 amp that it is now part of. I lit the tube with a 6.3 volt filament transformer.
In both cases the units work well, exhibiting roughly unity gain. Clipping, at least to my ears, has not been a problem and the sound quality changes are pretty much as expected.
Best,
John
I took a 1 ampere, dual bobbin, 28vct (a 14,0,14 center tap), cut the centerlink and paralleled the coils for a 2 ampere 14v transformer. Well, this ran cooler and one can turn the volume knob all the way to the top without clipping. Probably, I could have kept the 12v transformer and simply changed the board's power diodes to schottky.
So far, this buffer is fairly appreciable for buffering the computer, and I didn't need the EQ anymore. The bass harmonic is amazing. Just one inexpensive tube can do this?
So far, this buffer is fairly appreciable for buffering the computer, and I didn't need the EQ anymore. The bass harmonic is amazing. Just one inexpensive tube can do this?
Replacement 6n3 for ECC82?
Is 6n3 can replace (replacement) this schematic with the ECC82 or some changes are needed.
If necessary you should be?
I need this because I have a ECC82.
Thanks for your help!
Hi,This, which is the topic of the thread (as in post 1) can run:
6N3P, 2C51, 5670, 6CC42, 6385, 396a
Although it doesn't appear to be specifically appropriate for any of them
That's what it looks like.
Does yours have this schematic?
This circuit does have poor quality problems, but hum isn't one of its problems.
Is 6n3 can replace (replacement) this schematic with the ECC82 or some changes are needed.
If necessary you should be?
I need this because I have a ECC82.
Thanks for your help!
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Hi,
Where can I find this on the net a similar project just to be with ECC82 or PCC88.
Thanks for your help!