I bought something crazy- now what should I do? Fender 160 PS Content

[ClaytonS15]

I found a 1975 or 1976 Fender 160 PS Vocal Amplifier and 2 3x10" speaker cabinets at a local thrift store for $200. So I bought it... Now what?

The good thing: All it needed was a clean up- I cleaned all the pots with contact cleaner. It has all original tubes. EVERYTHING WORKS (all six channels and the reverb). I can't believe it.

The bad: What do I do with a 75 pound, 160 watt tube head that apparently is designed to use two 3x10" speaker, 5.2 ohm cabinets???

I want to be able to use the thing safely without hooking up the two cabs. How do I do that? Can I hook up one cab only? Who knows?

If anyone has any ideas, please let me know. I'll add the owner's manual, schematic and some pictures I took shortly.

 

[Opsimath]

That is impressive. I'll be looking forward to input from the knowledgeable because I'm curious exactly how it would be used. I hope you'll be enjoying it soon!

 

[nmiller]

According to the schematic, the two output jacks are in parallel and coming off a single output transformer. Since it's a standard mono amp, you should be able to plug in one cab without an issue as long as it's the right impedance. The total load of 2.6 ohms is a bit tricky, though; a regular 2 ohm cab would probably be fine, but even with basses that's a somewhat unusual impedance. Two 4-ohm speakers in parallel should get you there.

I'm tempted to say that a single 4-ohm cab would probably be safe, too, though I really don't know how much of a mismatch the OT can tolerate.

 

[GAD]

Neat! Would need to know if the outputs are bridged to be able to answer the one or two cabinet question.

Impedance of the output matters a lot, and if the cabinets are each on their own channel (which I kind of doubt since it would then have been marketed as stereo which was a very big deal back then, but better safe than sorry) then running it with only one cabinet would be very bad.

To test, with a multimeter and the unit powered off, plug a cable into each output and see if you get continuity between the tips of each cable. If you do, chances are the outputs are bridged together.

 

[GAD]

Or, you know, read the schematic. LOL. I need more coffee.

 

[ClaytonS15]

Or, you know, read the schematic. LOL. I need more coffee.

And I need to learn how to read the schematic and use a multimeter correctly! Thanks for all the advice so far- keep it coming.

 

[ClaytonS15]

According to the schematic, the two output jacks are in parallel and coming off a single output transformer. Since it's a standard mono amp, you should be able to plug in one cab without an issue as long as it's the right impedance. The total load of 2.6 ohms is a bit tricky, though; a regular 2 ohm cab would probably be fine, but even with basses that's a somewhat unusual impedance. Two 4-ohm speakers in parallel should get you there.

I'm tempted to say that a single 4-ohm cab would probably be safe, too, though I really don't know how much of a mismatch the OT can tolerate.

Ok- so- if I connect the 2 5.2 ohm cabs into each output, that equals 2.6 ohms because it is wired in parallel? Interesting. Thanks for the thoughts... I have some thinking to do...

 

[AcornHouse]

You can use an attenuator to out put the correct ohmage. Of course, with 160 watts, it’s going to need to be one he!! of a big attenuator. Or, if you get a 2x12 cab and stuff it with two high watt capacity speakers that will give you the ohms needed (check with the schematic to find whether those two big cabs are wired in serial or parallel).

 

[Walter Broes]

On a heavy duty tube amp running those voltages, have the power supply caps replaced. Even if just to be on the safe side - they're getting up there in age.

 

[Nuuska]

Found the manual in net - seems those cabinets are 3x32ohm = 10,6ohms.

The outputs of the amp are parallel.
Two 6550 output tubes - but w 700V anode voltage.
Manual says it accepts other impedances, too - but does not elaborate.

Therefore a fairly safe bet is to get a 4ohm cabinet - like 2x12" 8 ohms each wired parallel.

 

[ClaytonS15]

Found the manual in net - seems those cabinets are 3x32ohm = 10,6ohms.

The outputs of the amp are parallel.
Two 6550 output tubes - but w 700V anode voltage.
Manual says it accepts other impedances, too - but does not elaborate.

Therefore a fairly safe bet is to get a 4ohm cabinet - like 2x12" 8 ohms each wired parallel.

Well, that sounds perfect, since I have a Fender 2x12" at 4 ohms for a Bassman head. Cool! And Walter, yes, I will have a tech go through this thing if I keep it (I think I will- it sounds great...) If anyone is interested in buying some Fender 3x10" PA cabs, let me know.

 

[Guildedlily]

What did you do with this in the end? Where do you use it?