Amp power/volume vs speaker ohms

This forum is for talking about all kinds of Peavey guitar amplifiers.
Post Reply
JudgeShredd
New Member
Posts: 6
Joined: Thu Apr 29, 2021 12:12 pm

Amp power/volume vs speaker ohms

Post by JudgeShredd » Sat May 01, 2021 2:31 pm

I researched the 32 speaker ohms threads etc for a couple hours so don't be hatin' lol. I have a decent understanding of ohms law and series/parallel wiring. This thread is related to my other post about Backstage 110 amp... The amp has overheating issues, but that's the other thread. For reference, the PO stated he replaced the reverb can, but amp was shutting down on overload(heat), but thought he had a loose ground wire and thought he had it fixed. With New Tolex, New Can and NEW Peavey footswitch, in the middle of an epidemic, I threw $65 at it. I love that it has Reverb and Sat channel.
1) Does it matter the polarity of the amp output speaker wires and which one is +. (Yellow and Blue wires)? Would it matter as to amp overheating?
2) The 65WRMS BACKSTAGE 110 is unbearably loud past volume 1 or 2. Pots seem to be functioning properly. Seems wrong for an amp designed for a
small backstage warm-up/practice amp. I would like to be able to control my post gain sound somewhere between silent and "Earschplitten
Loudenboomer".
< oldschoolers please guess who said that. I have built a little cab with 2 vintage full range 8" @ 8 Ohm Zenith speakers. Seems my only options for
impedance are wiring in series @ 16 Ohms and parallel @ 4 ohms. First I played through the cab on level 1 ish in 4 ohms configuration, keeping volume low and monitoring heat. Played it that way a dozen or so 1 hr sessions, then got tired of the above volume setting issue. So I rewired the cab to series @ 16 Ohms, figuring if that cut the amp power in half, I would get more range out of my 2 post gain pots (Normal Gain and Lead Gain). And supposedly protect the amp from the 4 Ohm impedance concern. But there is no detectable difference in volume setting, as in I can still only play on level 1. I've had the luxury of practicing a little longer, and the amp started with the overheating issue, which I suspect has been there all along. So I changed back to the factory config with the built in 10" speaker, (and she's still overheating/shutting down, hence my other thread about that, along with an increasing reverb feedback hum). I switched the polarity of the Yel/Blu wires at the 10" factory speaker with no perceptible change. So the question is: 2) Where is my thinking wrong about the impedance vs amp output/volume level setting? Is there another way to get a wider range from the volume pots? Does anyone have the somewhat rare Backstage 110 to compare, and/or do the other Backstage series amps behave the same?
3) To hook up the external cab, I simply made a couple crimp connect spades and ran the wires directly off the speaker out Yel/Blu wires. Can't think of a better way of doing that, but with the lid off for the overheating issue, I may look at installing a 1/4" out jack somewhere?
Please address one or all questions by number, and hopefully this will help others-- thanks boys.-

User avatar
Pappy B
Member
Posts: 762
Joined: Sun Jan 31, 2016 2:30 pm

Re: Amp power/volume vs speaker ohms

Post by Pappy B » Fri May 07, 2021 1:27 pm

I'm curious why you are concerned about a 32 ohm speaker. I might be wrong but every Backstage I've seen uses an 8 ohm speaker.

Look on the left side of the rear of the chassis and it should say how many watts at how many ohms.
The more I learn the more I realize how much I don't know.

User avatar
Enzo
Member
Posts: 9535
Joined: Fri Sep 12, 2008 10:24 pm
Location: Lansing, Michigan

Re: Amp power/volume vs speaker ohms

Post by Enzo » Fri May 07, 2021 4:06 pm

The polarity of the speaker has absolutely zero effect on amp heating. The amp has no idea what is connected, it only sees impedance.

You are making the mistake of confusing power with loudness. Going from 60 watts to 30 watts only reduces loudness by 3 decibels, just enough to detect by ear. You are turning it down anyway, so you are not getting 60 watts 5 watts out of a 60 watt amplifier are the same as 5 watts from a 30 watt amplifier.

Does it have an FX loop? Or preamp out/power amp in jacks? If so, put a volume control in that loop.

Post Reply