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    Building, troubleshooting and testing of these amplifiers should only be
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    the safety precautions around high voltages.

tube tone control?

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#23
Well, I don't have copyright permission to post the AX version, but here's a schematic of one I built last summer based on the same overall principles; it has some improvements over the original. Performance was quite good, but it just didn't fit into the needs of my current system, so the "nice" build has been shelved for the moment.
 

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#24
benny said:
That circuit looks a hell of a lot like a Baxandall tone control.

I would highly recomend this circuit. I have used a passive version of the Baxandall circuit before, and it has very impressive results, offering a very wide range of tonal variations considering just two controls, bass and treble... and set bass and trebble both in the middle, and in theory you're getting a completly flat frequency response from the circuit.

i attached a schematic from an old article i have that is acutually about anode followers... but it discusses Baxandall's tone control in there as this utilises an anode follower, so therefore, in the article, there was provided this highly simplified version of a Baxandall tone control.

I say you should build it... my 2 cents

cheers
Click to expand...
can you please send a picture with values?
 
#26
Max Robinson's design is "unity" gain. As I have stated previously, the large bottle count (4 for stereo) can be dealt with by replacing the cap. coupled cathode followers by DC coupled ZVN0545A source followers.

Max indicated DC heating. I think AC heating is OK, IF the Sovtek 12AX7LPS, a genuine 7025 equivalent, is employed
 

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#27
SY said:
Well, I don't have copyright permission to post the AX version, but here's a schematic of one I built last summer based on the same overall principles; it has some improvements over the original. Performance was quite good, but it just didn't fit into the needs of my current system, so the "nice" build has been shelved for the moment.
Click to expand...

I don't have the 6M11, but it seems to separate out to a 6EW6 and a 12AT7. I'm planning on building it, is the 6EW6 recommended? I have 2 and I have several 6EJ7s.
 
#29
On business trips, i would try different hardware tone controls.
This 'quest' for tone went on about six years.

I would use friends to do blind tests.

I did not want to use feedback tone controls for religious reasons,
seems all you're doing is recycling the bad things.

So short answer is the passive tilt won on all fronts.
Everyone could find their sweet spot with one knob.

I use lo-z so that wiring layout is not so critical.
But you can of course go hi-z.

.bruce
 
#36
ha I'm always open to try anything.

Did spend some years testing many tone topologies.

The only issue really is clipping.

How does it handle clipping ie dynamic range. The passive is more forgiving pleasing to the ear. but if you're not clipping then no matter.
 
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