Plugging from 8 ohms to 16 ohms in a Peavey Classic 50 410

secreature

Member
Messages
105
Today as I was playing around adjusting tone settings on my amp, I plugged the cable on the back of the amp from the 8 ohms input to the 16 ohms input to see if there was a difference and noticed that it brought out more punch to the amp. I have owned the amp for 21 years and never done this. I recently replaced all the tubes in the amp. I was wondering would this cause any damage to the amp in any way if I keep it plugged in the 16 ohms?
 

Kyle B

Member
Messages
5,074
Depends how loud you play. If you're playing rhythm guitar in a church, you'll probably be fine. If you like melting faces in the mosh pit, ya might wanna not do that...
 

kinmike

Silver Supporting Member
Messages
1,808
The 2X12 Classic 50 is meant to run at 16 ohms. The 4X10 is different?
 

Kyle B

Member
Messages
5,074
The 2X12 Classic 50 is meant to run at 16 ohms. The 4X10 is different?
hmmmm I checked the manual on Peavey website... the 2x12 and 4x10 are both covered by the same manual, and oddly it doesn't state the nominal impedance of the supplied speakers. OP should double check.
 

wyatt

Member
Messages
4,170
hmmmm I checked the manual on Peavey website... the 2x12 and 4x10 are both covered by the same manual, and oddly it doesn't state the nominal impedance of the supplied speakers. OP should double check.
IIRC, the Blue Marvels are 16 ohm speakers. Since I can't think of an easy way to wire four 16-ohms speaker sup for 8-ohms total load, I would assume the nominal impedance setting for the stock speakers is 16 ohms.
 

secreature

Member
Messages
105
hmmmm I checked the manual on Peavey website... the 2x12 and 4x10 are both covered by the same manual, and oddly it doesn't state the nominal impedance of the supplied speakers. OP should double check.
I looked at the back of my amp and the speakers are 16 ohms. They should be fine right?
 

Kyle B

Member
Messages
5,074
I looked at the back of my amp and the speakers are 16 ohms. They should be fine right?
It's not possible to wire 4 16 ohm speakers to equal 8 ohms. Which means you may have had this amp running "wrong" for years... :jo

Do you have an ohmmeter??? It's easy to verify. Just measure the resistance of the whole set (unplug the speakers and measure across the plug). Then, disconnect one wire from a single speaker (so it's not part of the whole set anymore) and it should give you pretty much the exact same reading. You won't get 16 ohms... you'll get something closer to maybe 10-12 (never mind why... just go with it ;)) If you have an 8-ohm setup, you'll measure somewhere around 5 ohms.
 

secreature

Member
Messages
105
It's not possible to wire 4 16 ohm speakers to equal 8 ohms. Which means you may have had this amp running "wrong" for years... :jo

Do you have an ohmmeter??? It's easy to verify. Just measure the resistance of the whole set (unplug the speakers and measure across the plug). Then, disconnect one wire from a single speaker (so it's not part of the whole set anymore) and it should give you pretty much the exact same reading. You won't get 16 ohms... you'll get something closer to maybe 10-12 (never mind why... just go with it ;)) If you have an 8-ohm setup, you'll measure somewhere around 5 ohms.
Thanks for the response. I don't have an ohmmeter. I played today and the amp sounded great
 

Kyle B

Member
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5,074

drbob1

Gold Supporting Member
Messages
27,845
All that said, most amps are perfectly happy operating at a 100% mismatch up or down, and the Peavey is no exception. The Classic 50s were road dogs, it'll be fine at either. But yeah, that cab has to be either 4 ohms or 16 ohms if it's got 16 ohm speakers. A picture of the wiring would reveal all!
 

enorbet

Member
Messages
46
With four speakers at 16 Ohms each by far the two most common ways to wire them is 1) Parallel - 4 Ohms, and 2) Series/Parallel - 16 ohms. Obviously if yours are wired Series/Parallel you're totally safe on the money now at the 16 Ohm output jack. You did zero damage to your amp (excepting possibly power tube lifespan) by using the 8 Ohm jack. It just put the amp in or closer to Class A which is "spongier" and less "punchy" partly due to less than the designed full output power.

If they are wired Parallel (4 Ohms) running off the 16 Ohm jack could conceivably cause damage (low loading) but that is doubtful since you would very likely hear crossover distortion which is highly offensive. Bottom Line = look at the wiring and determine which arrangement you have for peace of mind. Odds are you're fine now.
 

kinmike

Silver Supporting Member
Messages
1,808
From Peavey Forum:

Classic 50 Combos:

The internal speakers on these amplifiers should be connected to the 16 ohm jack.

The other (8 ohm) jack is intended for use with an extension speaker enclosure. The extension should also be 16 ohms.
There is a switching system in this jack, which uses separate taps on the output transformer. When an external speaker is connected, both 16 ohm speaker systems are now in parallel and the amp's transformer is selected to 8 ohms.

Roger Crimm
Peavey Customer Service
customerservice@peavey.com
 

kinmike

Silver Supporting Member
Messages
1,808
The implication is that the four ten combo has four 16 ohm speakers wired for 16 ohm total load. The two twelve has 8 ohm speakers wired for 16 total.

Today as I was playing around adjusting tone settings on my amp, I plugged the cable on the back of the amp from the 8 ohms input to the 16 ohms input to see if there was a difference and noticed that it brought out more punch to the amp. I have owned the amp for 21 years and never done this. I recently replaced all the tubes in the amp. I was wondering would this cause any damage to the amp in any way if I keep it plugged in the 16 ohms?
Plugged into the 8 ohm tap, you have been playing with a mismatch. It will definitely sound punchier with correct impedance.

Mike
 

Moontrills

Member
Messages
268
So if i have a 2x12 50 watt classic combo with 2 8 ohm blue marvel speakers, the speakers should be plugged into the 16 ohm jack? or 8 ohm? :jo
I've never had any issues with it and I can't remember which jack they are plugged into, but I'll be checking as soon as I get home.
Pardon my ignorance, but i'm a bit OHMophobic. Messing with my amp makes me nervous. The most I'll do is change tubes.
 

secreature

Member
Messages
105
From Peavey Forum:

Classic 50 Combos:

The internal speakers on these amplifiers should be connected to the 16 ohm jack.

The other (8 ohm) jack is intended for use with an extension speaker enclosure. The extension should also be 16 ohms.
There is a switching system in this jack, which uses separate taps on the output transformer. When an external speaker is connected, both 16 ohm speaker systems are now in parallel and the amp's transformer is selected to 8 ohms.

Roger Crimm
Peavey Customer Service
customerservice@peavey.com
Thanks! I did go to Peaveys forum and was told that being plugged in the 16 ohm is perfectly fine.
 




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