Ampeg GV-22 Speaker Wiring

[tdlunsfo]

I got this GV-22 on the bench for a restore and it appears to have the original speakers as they have the "red dots" listed on the schematic so they are 8 ohms and was confirmed by my DMM. What has me confused is that this amp and others online are wired in parallel giving me a 4 ohm load. The schematic appears to show them in series giving a 16 ohm load.. but the schematic also shows them wired to the 8 ohm tap and the 16ohm tap being used for NFB. My thoughts are to swap the 8 ohm tap to NFB and wire the speakers in series (16 ohm) which would put 16 ohm speakers on the 16 ohm tap.... but I also don't want to mess with the "mojo" if it was intended to be an 8 ohm tap into 16 ohm speakers.
Thoughts?

[Enzo]

Leave the NFB alone, it is where it belongs. It works on signal voltage, not load impedance.

Schematic also calls for OT type OT-215. IS that in fact the OT in your amp?

Your amp has worked wired this way for how many decades? No particular reason to change it. That said, if you indeed have an OT-215, you could rewire them for series and see if you like the result.

[Helmholtz]

The schematic shows the speakers connected to the 16 Ohm tap as long as there's no external speaker plugged in.
Then the ext. speaker jack switches to 8 Ohm, which makes sense.

[tdlunsfo]

I'm not trying to change anything, the wires where disconnected when I got it and I'm merely trying make sense of it. The OT doesn't say 215 on it but it does have 8950015 and 682 022. I'll have to look it up. Hemholtz, looking at it closer and your right, it is wired through the 16 ohm tap with no ext speaker connected and these speakers need to be wired in series like the schematic shows. Where I got confused is I was looking at the external jack as the main speaker jack like a dummy.

[tdlunsfo]

Looks like 8950015 is an OT-215 so I think we're good now.

[J M Fahey]

IF you have the proper load resistors, drive your amp *just* to clipping into 4-8-16 ohms and check which delivers most power, period.
Measuring beats guessing any day of the week.

Then wire speakers to that value.

[J M Fahey]

it appears to have the original speakers as they have the "red dots" listed on the schematic

Red dot is not a brand, model, or even indication of impedance, only shows polarity, the red dot terminal being positive.

With a battery, positive to red dot, negative to other terminal pushes cone forward.

[tdlunsfo]

I looked at other ads for this amp and they have the same speakers, in fact the shot above is from one of those ads. Already performed the battery test and confirmed the red dots are positive. DC resistance shows them at 8 ohms. Most of the amps have them wired in parallel but I found one that had them in series. I just find it doubtful that Ampeg drove a 4 ohm load with a 16 ohm tap but I guess anything's possible.