• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

832A Push Pull 5W

vmps said:
how many watts are you getting?
vmps
Haven't measured it but it is pleanty loud. I took the amp to the local Sound Advice store to audition some speakers. It filled the 15x15 sound room when connected to a pair of martin logan electrostatics. I have 90db efficiency speakers connected to it and haven't turned it up past about 20% on the volume.
 
33.44dB gain (47 times the input). That is why with the 20% volume rotation being enough. Not a good thing to have a short throttle. Will give problems with really sensitive speakers. See about the Nelson Pass F4 argument on that.
 
vmps said:
hi kuroguy,

do you mind to show the power supply you alter from the original schematic ?

vmps
No need for a schematic. I just used two power transformers, one for the 200 volt supply and another one for the filament supply. I also added a time delay relay and switched the primary of the 200 volt transformer with the delay relay.
 
salas said:
33.44dB gain (47 times the input). That is why with the 20% volume rotation being enough. Not a good thing to have a short throttle. Will give problems with really sensitive speakers. See about the Nelson Pass F4 argument on that.
Let me clarify that. I keep the volume at about 20%while listening at work. when doing seriously listening it is up at around 50-60%.
 
kuroguy said:

Haven't measured it but it is pleanty loud. I took the amp to the local Sound Advice store to audition some speakers. It filled the 15x15 sound room when connected to a pair of martin logan electrostatics. I have 90db efficiency speakers connected to it and haven't turned it up past about 20% on the volume.

kuroguy said:

Let me clarify that. I keep the volume at about 20%while listening at work. when doing seriously listening it is up at around 50-60%.


Thanks for the clarification, I thought that you didn't use more than 20% in general. 50-60% sounds like more of a comfortable rotational range.
 
#1
 

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Latest 832 Schematic

mayham said:
Hi there,

Does anybody have the schematic from that site lying around? As a return favour here's the URL to my DIY 832a (gu32) amp design and construction:

The latest schematic posted on DIY 832a before the page went offline is this one. Voltage has been specified on caps.

Francois
 

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