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12bh7 in place of ecc82

Hi to Everyone !

My long term project would be to build a very minimalist line buffer/driver to use, with a pot in front of it, as a line stage (no voltage gain required)
Reading on web I see that many well received tube power amps has a 12bh7 as driver of the power stage.
I understand is a very powerful tube and I guess also nice sounding
I am very bad at building circuit and I would buy a kit
I see a lot of kit for the ecc82
Can I put a 12bh7 at the place of a ecc82 without big problem ?
As I said I need just a nice line driver, no voltage gain required at all
Thanks and kind regards,
gino
 
I've read lots of positive remarks from posters swapping 12BH7 for 12AU7/ECC82.
Just be aware that the 12BH7 draws more heater current than a 12AU7, 0.6 amps @6.3v versus 0.3 amps @6.3v for the 12AU7.
jeff
http://www.mif.pg.gda.pl/homepages/frank/sheets/093/1/12AU7A.pdf
http://www.mif.pg.gda.pl/homepages/frank/sheets/093/1/12BH7A.pdf

Hello ! actually I made the same myself
I have this one

Croft acoustics micro tube preamp (Used)SOLD

The line stage is a buffer made with an half of ecc82 per channel
Not having a turntable I took out the two ecc83 of the phono stage and put a 12bh7 in place of the ecc82
I prefer the sound that is more robust now
But I would like to find a kit (at least a pcb) of a buffer employing a ecc82 (so much more common) and use instead a 12bh7
This tube is powerful, clean, I like it very very much
With a nice attenuator in front of it could be a very simple but robust and nice sounding line stage
Thanks and regards,
gino
 
Hi thank you for the advice.
But I need a kit to have any hope to succeed
I do not like my actual preamp

img_0268.jpg


it is too crowded, tubes are horizontally placed (I much prefer vertical position), I do not like the pot but I do not want to modify it.
Much better something completely new.
Now that I know that a 12bh7 is so much more powerful and it works more or less in the same conditions of a ecc82 I am quite stick with.
If only I could find a kit of a buffer using a ecc82 I think I would be done.
By the way I read that this very tube is quite common in the driver stage of well received tube power amps, like Manley for one.
So the search is on.
And as I said I strongly need a kit that can be a robust base to start with
Thanks again and kind regards,
gino
 
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- ECC99 and 12BH7 are quite different tubes
- no, the 12BH7 is not "so much more powerful".
- yes, it does sound much better than 12AU7/ECC82. At least NOS tubes do, I don't know about the modern russian copies...
- yes, you can swap them, IF the heater transformer can supply 0.6A of heater power instead of 0.3A per tube. If it can't, the voltage will be lower and the transformer may heat up. It would be a pity to misuse a good and expensive NOS 12BH7 - it needs between 6.2v and 6.3v, no more, no less. If the voltage is lower, it would behave like a USED, dead tube. If it is higher, its lifespan would be halved.
- so no, it's not a good idea to buy a chinese ECC82 kit, unless you are prepared to modify it. It would be simpler and better to DIY...
 
- ECC99 and 12BH7 are quite different tubes
- no, the 12BH7 is not "so much more powerful".
- yes, it does sound much better than 12AU7/ECC82. At least NOS tubes do, I don't know about the modern russian copies...

Thank you. May be I have understood why they all speak about the ecc82 and not of the 12bh7
I read that the 12bh7 is less common on the market.
It is an old tube with little new production. So the ecc82 is much more available ?
But what makes me wonder, if it is really better why no kits, no projects ???
I would expect a bigger interest on this tube

- yes, you can swap them, IF the heater transformer can supply 0.6A of heater power instead of 0.3A per tube. If it can't, the voltage will be lower and the transformer may heat up. It would be a pity to misuse a good and expensive NOS 12BH7 - it needs between 6.2v and 6.3v, no more, no less. If the voltage is lower, it would behave like a USED, dead tube.
If it is higher, its lifespan would be halved.
- so no, it's not a good idea to buy a chinese ECC82 kit, unless you are prepared to modify it.
It would be simpler and better to DIY...

I understand the power supply issue ... is not a problem for me to add a more powerful power supply. This is not a major problem
a 12V/2-3A regulated power supply can be found easily off the shelf

Yes, the 6v6 cathode follower Tinitus mentioned above would be a great choice.

I have to read the thread first carefully, but as I said I need a kit :rolleyes:
It is my only chance to get something that works :eek:
Thanks again
Regards, :)
gino
 

tinitus

Ex-Moderator R.I.P.
2005-11-24 1:47 am
ah, for simple 'tube rolling', yes ofcourse

I was more thinking of 12BH7 and ecc99 being 'similar' because they are both highly regarded for being very good driver tubes for power amps
no, pin out type is not my concern

to try and be funny, could also say the octal 6SN7 is equivalent to another 9-pin type...which is it, I don't remember now
 
6SN7 is similar to 6CG7/6FQ7, but with a different base.

My take on 'tube rolling' is that if a circuit designed for ECC82/12AU7 gives genuinely better performance with a 12BH7 then either the circuit was poorly designed or the ECC82 happened to be a poor choice for that particular application. 'Everybody knows' that the ECC82 is a poor choice for any audio application, yet I found that in a quick lashup test circuit an RCA 12AU7 gave the lowest distortion; 6CG7 etc. were worse.
 

tinitus

Ex-Moderator R.I.P.
2005-11-24 1:47 am
or it was designed for the 12BH7, and he or the supplier replaced it with ecc82 instead, because the 12BH7 had gotten harder to get
or it have just been a simple toss around because the riias and pickups needed different gain settings :clown:

maybe worth to remember that many of these amps may be from a time where tubes were much harder to get hold of than they are today
and often the suppliers of these kind of amps were very clever people who were unaware that they actually knew very little about it
 
Ah, that ineffable euphony... it does not come *only* from the lowest possible distortion! Lowest distortion is of course a design goal, but there are also other, more subtle, aspects of musicality...

In my experience, and in *my* headphone amplifiers, none of the 12AU7/ECC82 I've tried (RCA, Philips, JJ, 5814, etc.) sounded as musical and realistic as the different NOS 12BH7 I have, at any bias current (CCS loaded, LED biased). YMMV.
 
I read that the 12bh7 is less common on the market.
Indeed, but it is still made in Russia. I don't know what it's worth.

So the ecc82 is much more available ?
But what makes me wonder, if it is really better why no kits, no projects ???
I would expect a bigger interest on this tube.
Yes, the ECC82 is much more available, they can get tons of them for cheap in China, where most of the cr*ppy kits come from.
The 12BH7, OTOH, is much less known...

I understand the power supply issue ... is not a problem for me to add a more powerful power supply. This is not a major problem
a 12V/2-3A regulated power supply can be found easily off the shelf
Very well, but you need a good *adjustable* regulated PSU. It's not 12v that you need, it's 12.6! ;)


I have to read the thread first carefully, but as I said I need a kit :rolleyes:
It is my only chance to get something that works :eek:
Ok! If you change the PSU, the tube, the capacitors and probably some other parts, you'll get a good buffer! We're here to help! ;)
 
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Forgot something: the 12BH7 sounds good as a voltage amplifier. I personally don't know how it performs as a cathode follower. Probably good...

There are better theoretical tube choices for a cathode follower for a lower output impedance, like the ECC99 or ECC88. Or a triode strapped pentode, like Salas' 6V6 schematic... Or a trioded EL84...