• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
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    the safety precautions around high voltages.

preamplifier

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Gordy

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kevinkr

kevinkr

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ray_moth said:
I'm with Gordy on this.
Click to expand...


Me too.. Early on I designed a generally similar circuit and found it sonically inferior to just about anything you could imagine.. :D

Still other options to those listed above could include a simple amplifier stage using half of an ECC99 or 5687 per channel for a gain of around 22dB or so and fairly low source impedance with no fdbk.
 
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Wavebourn

Wavebourn

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kevinkr said:
Me too.. Early on I designed a generally similar circuit and found it sonically inferior to just about anything you could imagine.. :D

Still other options to those listed above could include a simple amplifier stage using half of an ECC99 or 5687 per channel for a gain of around 22dB or so and fairly low source impedance with no fdbk.
Click to expand...

That means, the Devil is in details, and the same cat may be skinned by multiple ways.

Generally similar circuit (2 stage amp with serial feedback by voltage) was used in one of my first hybrid amps. The sound was unbelievable real.

Here is the driver schematic (I found it in my very old papers) attached.
 

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aardvarkash10

aardvarkash10

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here's the issue though guys - we are looking for a pre- for a very specific application. It would appear that it actually doesn't need gain since it has line level input, but has to drve and unknown load.

Kinda makes amplifying stages a non-issue surely. If ever there was a case for a passive pre or perhaps a CF buffer set-up this would be it...
 
Wavebourn

Wavebourn

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aardvarkash10 said:
here's the issue though guys - we are looking for a pre- for a very specific application. It would appear that it actually doesn't need gain since it has line level input, but has to drve and unknown load.

Kinda makes amplifying stages a non-issue surely. If ever there was a case for a passive pre or perhaps a CF buffer set-up this would be it...
Click to expand...

In such case may I recommend similar stages? I used my SS-only version in my Tower-II amps (now in Tower-V) to drive heavy to drive 100W speakers, it sounds gorgeous!

176843d1276931155-sy-pete-millett-crossover-afbb.png
 
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