Ok great, well at least I have a gameplan then, I'll twist them up and maybe look at changing out those input wires. The ones he used are really tiny gauge silver wires, I wonder if silver picks up more noise than copper? What gauge/type would you suggest?
The wire size is not critical, and can be small.
Are you sure that the transformers increase the input impedance?
They may be 1:1 transformers for ground isolation. If they increased the
amplifier input impedance, they would also step down the input voltage
and likely increase the noise.
Are you sure that the transformers increase the input impedance?
They may be 1:1 transformers for ground isolation. If they increased the
amplifier input impedance, they would also step down the input voltage
and likely increase the noise.
Yes, Im sure, they're 2:1 step down transformers. I had read that using input transformers on these boards would attenuate the signal some because obviously 250 watts is a bit much for a single driver 😀
And also that the transformer would increase the input impedance which I had read is a good thing for audio quality. To be honest it was a big fat guess on my part and may have contributed to the increase in hum and hiss. I use a high quality power conditioner with this amp so hopefully that cuts down on ac line noise. But Im pretty sure at this point that something in the amp is picking up EMI or some other type of noise. Seems logical that the wiring used might be the culprit but I am unsure. I did pay a pretty penny to have this amp worked on and as one other person said it looks like a messy job. I didnt know the difference but live and learn. I wont name the individual who worked on it but they do have a long record of mods for the online community and I wasnt entirely happy with the transaction for various reasons. Not the least of which was a 6 month wait ! But maybe I can save the amp and learn in the process.
And also that the transformer would increase the input impedance which I had read is a good thing for audio quality. To be honest it was a big fat guess on my part and may have contributed to the increase in hum and hiss. I use a high quality power conditioner with this amp so hopefully that cuts down on ac line noise. But Im pretty sure at this point that something in the amp is picking up EMI or some other type of noise. Seems logical that the wiring used might be the culprit but I am unsure. I did pay a pretty penny to have this amp worked on and as one other person said it looks like a messy job. I didnt know the difference but live and learn. I wont name the individual who worked on it but they do have a long record of mods for the online community and I wasnt entirely happy with the transaction for various reasons. Not the least of which was a 6 month wait ! But maybe I can save the amp and learn in the process.
Here is a 150 w MMA-8150t C$80 in canada. It has a useful dual RCA jack input (necessary the other is only for telephones). Freight to me is $63 but would be less to you, check your own ebay. Peavey MMA 8150T - 8 channel Modular Mixer/Amplifier WITH BOSE 102 eq module | eBay
Here is a Peavey M-3000 in canada allegedly working US$179 PEAVEY M-3000 VINTAGE POWER AMPLIFIER #1723 GOOD USED WORKING VINTAGE CONDITION | eBay
I had to put new rail caps in my M-2600 to get watts up to rating.
All my M-2600 MMA-875t MMA-81502 are silent. No reengineering required.
Here is a crown 180ma in Cleveland OH for $40 + freight. Crown 180ma 4 Channel 80w Professional Commercial Power Audio Mixer Amp | eBay
Also mono, 80w.
Mono.
Personally I listen mostly at 1/4 to 1 watt on 99 db 1w1m speakers. Peaks of 70 w allow the cannon shot in 1812 overture to sound impressive.
Here is a Peavey M-3000 in canada allegedly working US$179 PEAVEY M-3000 VINTAGE POWER AMPLIFIER #1723 GOOD USED WORKING VINTAGE CONDITION | eBay
I had to put new rail caps in my M-2600 to get watts up to rating.
All my M-2600 MMA-875t MMA-81502 are silent. No reengineering required.
Here is a crown 180ma in Cleveland OH for $40 + freight. Crown 180ma 4 Channel 80w Professional Commercial Power Audio Mixer Amp | eBay
Also mono, 80w.
Mono.
Personally I listen mostly at 1/4 to 1 watt on 99 db 1w1m speakers. Peaks of 70 w allow the cannon shot in 1812 overture to sound impressive.
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If you short the amplifier inputs with a shorted RCA plug, what noise is there, if any?
If you hear any hum, is it a low pitch 60 Hz, or a higher pitch 120 Hz?
Reducing the gain by half won't limit the power output of the amplifiers, though.
The preamp is almost certainly still able to drive the power amps to full output.
Also it's possible that twisting the silver input wires tightly could damage them.
If you hear any hum, is it a low pitch 60 Hz, or a higher pitch 120 Hz?
Reducing the gain by half won't limit the power output of the amplifiers, though.
The preamp is almost certainly still able to drive the power amps to full output.
Also it's possible that twisting the silver input wires tightly could damage them.
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Shorting made no difference, I also tried every type of grounding device, no change. It seems to be coming not from outside but from inside the amp somehow. Seems like a 120hz hum with a good measure of hiss on the mids and tweets as well.