• 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.

Recording from a PA

I have built 2 tube monoblocks PAs.

I wanted to listen to them and sonically decide what sounds better. I have about 4 variations to try out. One is with or without GLOBAL negative feedback etc. My issue is I'm having a hard time remembering and comparing what I'mhearing. Is there a way to record the output for later playback, making it easier to decide what sounds best?
 
Do you mean acoustically or electrically?

I would just play one for a week or two, then go to the next version for another week or two.
There's no point in trying to instantaneously A/B them. that's not how you listen to them.
You want a long term reaction.
 
That sort of stuff is done on YouTube all the time. You'd need a decent mic though.
But A/B comparisons are of little use. That's how bad speakers are sold in stereo stores.

Bad speakers can sound good in a brief, carefully set up comparison, but will be intolerable over time.
Same goes for other types of audio comparisons.
 
Koda,
I found this hookup diagram in the link you provided. Does anyone have some advice to select R3 and R4?
setup.png
 

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  • setup.png
    setup.png
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This: The two small resistors are the 22k:2k, the big one is the load for the amp. If you use the speaker as a load, you could omit the big resistor.
I don't think the pic you posted is relevant to the thing you want to test 🙁
1671762667678.png
 
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