I can assure you that you get it wrong; the cathode voltage follows the grid voltage. Any serious vacuum tube book will tell you that.
Fairchild 670 Solid State Concept
- Thread starter Majestic12
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abbey road d enfer said:
Anyway, let us put the case to rest, since nobody else seems to be interested in it.
Best Tobias
there is a 8 uf cap connecting the cathodes,
or 2 ea 4 uf if you wann get techniaclle,
or 2 ea 4 uf if you wann get techniaclle,
I STAND CORRECTED!
Sorry for the bullshit I wrote, I measured again and this time everything looks like it should.
Since it is the 660 cathode circuit, the voltage on the cathode changes quite a bit during gain reduction, but it really follows the grid and nothing else!
And the grid voltage is just the rectified voltage after the transformer and nothing else!
I do not know what I measured the first time, but it was wrong.
Sorry for the bullshit I wrote, I measured again and this time everything looks like it should.
Since it is the 660 cathode circuit, the voltage on the cathode changes quite a bit during gain reduction, but it really follows the grid and nothing else!
And the grid voltage is just the rectified voltage after the transformer and nothing else!
I do not know what I measured the first time, but it was wrong.
Hi Analag
On the subject of eliminating thump by improved cathode circuit design, I believe you used that in your Poorman 660 Limiter.
After >1yr of frequent use (with no issues at all 8) I find the Poorman 660 to *really* be with no thump at all
Would you care to elaborate any on that design aspect?
I think it is the transistor in the cathode ciruit which does the job. It is a constant voltage sink or so?
Any clarification would be welcome.
Cheers
On the subject of eliminating thump by improved cathode circuit design, I believe you used that in your Poorman 660 Limiter.
After >1yr of frequent use (with no issues at all 8) I find the Poorman 660 to *really* be with no thump at all
Would you care to elaborate any on that design aspect?
I think it is the transistor in the cathode ciruit which does the job. It is a constant voltage sink or so?
Any clarification would be welcome.
Cheers
alexc said:Hi Analag
On the subject of eliminating thump by improved cathode circuit design, I believe you used that in your Poorman 660 Limiter.
After >1yr of frequent use (with no issues at all 8) I find the Poorman 660 to *really* be with no thump at all
Would you care to elaborate any on that design aspect?
I think it is the transistor in the cathode ciruit which does the job. It is a constant voltage sink or so?
Any clarification would be welcome.
Cheers
Which is one of the reasons I never made the circuit public. Anyway improvements were made to it in the Monsterchild 670.
