"4 ohm minimum" on a tube amp?

[VOLVO)))]

No switch, nothing. What do I do with my 16 ohm cab?

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[RAGER]

I'd play it anyways   The other way around I'd be concerned

[Corey Y]

Lots of old amps just have a minimum impedance rating instead of switchable. Above the minimum shouldn't be a worry, so long as you're not going below. Even then with some amps it's not a worry if they have really robust transformers, just have to be careful. My YBA-1 is 8 ohm minimum and I run it at 4 ohm consistently, but it has pretty beefy transformers to be sure. If it was switchable mismatching would be a lot more worrisome.

[Mr. Foxen]

Likely to be able to rewire the cab to 4 ohm.

[VOLVO)))]

Likely to be able to rewire the cab to 4 ohm.

That eliminates my emergency plan when one of my heads goes down.

[Jake]

I used to run a 16ohm cab from a 4ohm Bassman all day. It may have been an inefficient configuration, but it worked just dandy. I was too lazy to rewire cabs, btw. Still am.

However, don't run a mismatch where you dump a small impedance into a large impedance load. Flyback voltage will be really problematic and can cause death.

[dunwichamps]

dont run a mismatch where you dump a small impedance into a large impedance load. Flyback voltage will be really problematic and can cause death

[dunwichamps]

Lots of old amps just have a minimum impedance rating instead of switchable. Above the minimum shouldn't be a worry, so long as you're not going below. Even then with some amps it's not a worry if they have really robust transformers, just have to be careful. My YBA-1 is 8 ohm minimum and I run it at 4 ohm consistently, but it has pretty beefy transformers to be sure. If it was switchable mismatching would be a lot more worrisome.

that is a better mismatch

[VOLVO)))]

sigh.

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[VOLVO)))]

Jesus fucking Christ, this amp is a machine. Four or two ohms. Christ.

https://docs.google.com/viewer?a=v&q=cache:bpxqKxGqtrEJ:peavey.com/assets/literature/manuals/80343005.pdf+peavey+heritage+vtx+manual&hl=en&gl=us&pid=bl&srcid=ADGEESjfismoi4VCcQFHC72WfHuu_mwHWvkExvS34GG5c9sfmfbLRKWDWPB_X6mZPbIH61g5uo4NjMDv8TJC8iduT-w3hQRNN273VR4aBcVT96kY9WWcHyLgvT7fG1kbc-f9EaT9_g9P&sig=AHIEtbQuETrbMmJOoNy66DOChgbzuelKlw

Acutally, the manual says above four will give slightly decreased power, but it's still fine. I couldn't find this fucker on my phone.

[Jake]

Just run it with eight 16ohm cabinets then.

You're welcome.

[VOLVO)))]

The Butcher had taps for FOUR 16 ohm cabinets. It was sick.


This is replacing my JCM800 in my rig, by the way.

[VOLVO)))]

It's also a fierce dirty bass amp. Paired with the 370.... noise complaint city.

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[Hemisaurus]

Tech thread if you want a tech to respond y'know

Is it a Peavey? I've seen a few Peaveys do 4 ohm min. on tube amps, you have three choices I can think of.

1. rewire your cab to match
2. get one of those impedance matching trannies from weber ($30 maybe)
3. trust the manufacturer and run it

[VOLVO)))]

Cant rewire the cabs. They have to be 16 ohm in case one of my heads goes down on me.

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[dunwichamps]

Cant rewire the cabs. They have to be 16 ohm in case one of my heads goes down on me.

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make it switchable no QQing

[Jake]

Slightly off topic, but as soon as I find someplace that has one in stock, this is my $150 backup amp:



I'm sure it's gonna need a pedal or two to make it sound good, but it'd make a pretty convenient emergency rig, me thinks.

[bitter]

Dig it!

I always thought they should have made a Ma Deuce 2x50 watt, and housed it in a big muff sized enclosure.

[VOLVO)))]

Actually, Jake, those sound half-decent without any help. The overdrive is brutal.


In other news, I think this amp sounds like shit for clean.

[servantofthedead]

One of my old Univox tube amps has a single speaker out labeled 8 ohm minimum...I've always been concerned to try anything else, but would I be able to run a 16 ohm cab with it without fear of failure?

[dunwichamps]

One of my old Univox tube amps has a single speaker out labeled 8 ohm minimum...I've always been concerned to try anything else, but would I be able to run a 16 ohm cab with it without fear of failure?

I dont quite understand what 8 ohm minimum means, it could be this is an 8 ohm tap or this is a higher value tap but 8 ohm is the minimum. if its a 8 ohm tap you usually dont wanna run a larger impedance than the tap as this causes flyback voltage on the primary which can cause problems and sometimes death, Imagine for a second why its awful to run a tube amp with no load, the flyback is immense in this case as the load is infinity. So if your playing heavy and hard its better to run a lower impedance on the tap than a higher one

[Mr. Foxen]

Imagine for a second why its awful to run a tube amp with no load, the flyback is immense in this case as the load is infinity.

And also note that the output jacks on most amps are shorting, because its better to have a total short (low to no impedance) than total open (massive/infinite impedance).

[dunwichamps]

Imagine for a second why its awful to run a tube amp with no load, the flyback is immense in this case as the load is infinity.

And also note that the output jacks on most amps are shorting, because its better to have a total short (low to no impedance) than total open (massive/infinite impedance).

yes good point to add, better to short the amp to ground then to run it open

Another option that wouldnt be awful would be to have a 4 ohm resistor tied from the output jacks to ground when the jack is unused to provide a non zero load thats not large. I guess problem is that it could burn the fuck up if someone play louded into it since couldnt too large to fit in the amp

[Mr. Foxen]

I was thinking about that and those thermal trips you get in SS amps, I assume the sensor attached to the heat sink does that, have one of those on the resistor that cuts the whole amp out.

[justinhedrick]

Actually, Jake, those sound half-decent without any help. The overdrive is brutal.


In other news, I think this amp sounds like shit for clean.

probably biased cold.