MeToo2
Well-known member
Having built some valve based equipment I'm getting bitten by the bug.
One potential project I'm thinking about is a poor man's v76.
Why?
You can buy an original, but it costs a fortune and they are difficult to get hold of. Even if you get one you have to recap it and potentially find new transformers etc. as well as a rack mount.
Now obviously you can also buy a TAB version off the shelf for a goodly sum of money (and I have no doubt that it is an excellent reproduction of the original), but I have a hunch that there's interest at a much lower price level.
So why make a poor man's version?
Because V76 have been called the rolls royce of preamps
Because they are pentode based (whereas most diy designs seem to be triode based)
Because they are very quiet
Because of a rising interest in ribbon mics, especially for drums (which require high & quiet gain)
Because it looks tough to do (I've seen other people reporting difficulty getting their build not to oscillate)
Here's a straw man for some parameters that I came up with.....
Main use case: virtually no features except for adjustable high gain / quiet gain usable for ribbon mics for recording drums in small project studio
-> switchable minimum 3-70dB gain or more (aim for 76 and same steps as v76). 106dB S/N ratio or much better (aim for 120)
-> no phantom power in first pass
Cost price: way less than 600 euros for 3 or 4 channels including case PSU etc.
-> Valve choice: no ef804s or ef804 (see cost price) -> ef86 clone or 6j32p level
How accurate: first order reproduction. Using modern components. NOT worrying about metallurgy of transformers etc.
-> Edcor, Sowter or other off the shelf transformers
Stable: No oscillation or motor boating!
General Character: like the V76S studio version or V76/80/120 broadcast version?
What do you think would be good starting points for such a project?
Has this been done before?
Is it a lost cause?
Any other thoughts?
Thanks for your input.
One potential project I'm thinking about is a poor man's v76.
Why?
You can buy an original, but it costs a fortune and they are difficult to get hold of. Even if you get one you have to recap it and potentially find new transformers etc. as well as a rack mount.
Now obviously you can also buy a TAB version off the shelf for a goodly sum of money (and I have no doubt that it is an excellent reproduction of the original), but I have a hunch that there's interest at a much lower price level.
So why make a poor man's version?
Because V76 have been called the rolls royce of preamps
Because they are pentode based (whereas most diy designs seem to be triode based)
Because they are very quiet
Because of a rising interest in ribbon mics, especially for drums (which require high & quiet gain)
Because it looks tough to do (I've seen other people reporting difficulty getting their build not to oscillate)
Here's a straw man for some parameters that I came up with.....
Main use case: virtually no features except for adjustable high gain / quiet gain usable for ribbon mics for recording drums in small project studio
-> switchable minimum 3-70dB gain or more (aim for 76 and same steps as v76). 106dB S/N ratio or much better (aim for 120)
-> no phantom power in first pass
Cost price: way less than 600 euros for 3 or 4 channels including case PSU etc.
-> Valve choice: no ef804s or ef804 (see cost price) -> ef86 clone or 6j32p level
How accurate: first order reproduction. Using modern components. NOT worrying about metallurgy of transformers etc.
-> Edcor, Sowter or other off the shelf transformers
Stable: No oscillation or motor boating!
General Character: like the V76S studio version or V76/80/120 broadcast version?
What do you think would be good starting points for such a project?
Has this been done before?
Is it a lost cause?
Any other thoughts?
Thanks for your input.