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Monaural record for balancing
Posted: Mon Nov 01, 2021 3:24 am
by Hydrolastic
Hello all. I am not quite there yet but i was looking at the sams on how to set the balance and its talking about using a monaural record with 1000 and 3000 cycle frequencies. Do i need this record ? If so what is it called. Where do i look? Screenshot of the Sams for clarification. Hydro
Re: Monaural record for balancing
Posted: Mon Nov 01, 2021 1:51 pm
by hermitcrab
does it have to play though the record player?... can't you do the same by injecting a 1000 Hz/ 3000 Hz sine wave into the inputs with a signal generator?
Re: Monaural record for balancing
Posted: Tue Nov 02, 2021 12:27 am
by electra225
I set mine with a mono LP. I don't see why you couldn't inject a signal at the recommended frequencies into the phono input.
Re: Monaural record for balancing
Posted: Tue Nov 02, 2021 12:41 am
by TC Chris
Jut guessing here--this must be a bi-amp model, and the goal is to get the bass vs treble balanced against each other (i.e., not balancing L vs R)? If so, then perfection isn't required. Just get it to sound right. Same goes for L vs R, actually--if L and R sound about as bassy as each other, and as trebly when it comes to that, it's good enough. This isn't a matter of certifying a measuring instrument--it's an audio device.
Chris Campbell
Re: Monaural record for balancing
Posted: Tue Nov 02, 2021 1:38 am
by electra225
Those instructions are for the 88 and 93 series amps. All they are interested in is that the output of the channels are the same. Connect a VTVM to each bass speaker. Then adjust the balance control until the output is the same. The meter would be set on AC volts, probably the five-volt scale would be okay. I don't know why you would need a fancy input device, as long as you get a mono signal. The bi-amps have a phono balance control in the tuner. All they balance is phono input to the amp. There is no balance control, per se, on the bi-amps after the early 1959 jobs. The reason I'd run it thru the phono input is that you will bypass one section of the tuner (pre-amp) if you feed it to the tape input or to the input of the amplifier. You want to get the first stage of pre-amp in there when you balance the channels.
Re: Monaural record for balancing
Posted: Tue Nov 02, 2021 3:13 am
by Hydrolastic
Thank you guys, Not having much experience with electrical. I don't know yet how much is precision and how much is art. My buddy offered me a signal generator. Sounds like something fun to look into. I will keep an eye out for a test record though.