Confusion on ohms and cabinets for amps.

[PRSfanboy46]

Sorry for flooding the forum today but I am curious about amps and impedances.

So the head I am looking at is the orange micro dark terror, and it says on on the back of the head with the speaker output and it says "Min 8 ohms". The cabinet I want is a matching orange 1x12. That says it's 60 watts at 16 ohms. So, could I run an 8 ohm amp through a 16 ohm cabinet?
Thanks.

 

[HANGAR18]

Sorry for flooding the forum today but I am curious about amps and impedances.

So the head I am looking at is the orange micro dark terror, and it says on on the back of the head with the speaker output and it says "Min 8 ohms". The cabinet I want is a matching orange 1x12. That says it's 60 watts at 16 ohms. So, could I run an 8 ohm amp through a 16 ohm cabinet?
Thanks.

I believe so. You cannot go less than that, say 4 ohms.

 

[veinbuster]

Yes, you can run an 8 ohm amp into a 16 ohm cab.

 

[PRSfanboy46]

Yes, you can run an 8 ohm amp into a 16 ohm cab.

Nothing will break, implode, explode or blow up? Is it just better to do half and half, half of a 16 ohm cab going into an 8 ohm amp, vice versa 8 ohm amp going into a 16 ohm cab? I think the bad thing to do is 16 ohm amp into an 8 ohm cab. that would blow the speaker.

 

[dmatthews]

That's why the amp says "Min 8ohm". It's a minimum. 16 ohm is no problem.

 

[Kiwi]

Your amp will be fine with a speaker cabinet at either 8 or 16 ohms.

You are not fine with a 4-ohm speaker.

General rule: Mismatch is OK as long as the amp sees a higher load, by 1 step. (Amp that wants to see 4 ohms is OK with with 8, but maybe not 16 ohms.)

These are not dumb questions, by the way, and they are questions you should definitely be asking before you hook up tube amps.

We all had to learn this stuff ourselves back in the day, and we're here to help.

=K

 

[PRSfanboy46]

That's why the amp says "Min 8ohm". It's a minimum. 16 ohm is no problem.

So would it just be general rule of thumb to go half and half considering amps and their impedances? 8 ohm head going into a 16 ohm cab the sweet spot?

 

[PRSfanboy46]

Your amp will be fine with a speaker cabinet at either 8 or 16 ohms.

You are not fine with a 4-ohm speaker.

General rule: Mismatch is OK as long as the amp sees a higher load, by 1 step. (Amp that wants to see 4 ohms is OK with with 8, but maybe not 16 ohms.)

These are not dumb questions, by the way, and they are questions you should definitely be asking before you hook up tube amps.

We all had to learn this stuff ourselves back in the day, and we're here to help.

=K

Well I assume anything under the minimum impedance load needed going into the amp would be harmful to it (like a 16 ohm head going into a 4 ohm cabinet) That would just be awful, but an 8 ohm amp going into a 16 ohm cab would be just fine? I think the general rule of thumb is going half half on impedances

 

[veinbuster]

So would it just be general rule of thumb to go half and half considering amps and their impedances? 8 ohm head going into a 16 ohm cab the sweet spot?

There is no half and half rule.

An amp is designed for a minimum load; e.g. 8 ohms. Never run it into anything less. Running it into a higher resistance cab will do the amp no harm. Whether or not it performs better is a matter of taste, but the speaker itself plays a bigger part in that than the the resistance itself.

 

[Straight_six]

So would it just be general rule of thumb to go half and half considering amps and their impedances? 8 ohm head going into a 16 ohm cab the sweet spot?

I wouldn't say that it is the sweet spot but it will work. The amp you are looking at (orange micro) actually has a solid state output transformer designed for 8 ohms so an 8 ohm cab would actually be the sweet spot as it is perfect match of impedance. A 16 ohm cab in your situation will actually produce less volume. I don't know the exact conversion but if the orange is 20w it would actually react more like 12w with a 16 ohm cab. This isn't 100% but if you are comparing speakers with the same sensitivity (rated in db) then it's pretty much spot on.

 

[RickP]

The ohm load is used to control output of the output transformer. It’s a reactive load that serves as a damper. Without the proper load the transformer, which has no internal means of limiting itself, with put out more power than its rated for, and will burn up. This is why you never want to run a tube amp without a speaker, as it will push hundreds of volts through the transformer and burn it out in a relatively short period.

As long as the load is higher than the rated output, you’re ok. Most guitar amps accommodate a 8 or 16 ohm load, the better ones also handle 4, and some (primarily bass amps) will go down to 2. So your 8 ohm amp is fine with a 16 ohm cab. You could even use two 16 ohm cabs in parallel, which makes an 8 ohm load. This is a good way to get more audible power from your amp, as doubling speaker area produces a lot more sound than simply doubling wattage.

There are devices to balance output and cabinet so you can use mismatched pairings and make them matched. I have a a Weber Z-Matcher for just that purpose. Do some web searches on speaker cabinet wiring to see what parallel, series, and series-parallel wiring do to the ohm rating, and what adding cabinets do. The rule of thumb is simple, equal or more is always ok. The worst it will do is lower the output, but no damage will occur. Less than rated will cause damage over time. How much time that is depends on the amp and how off the load is. Hope that helps you.

EDIT: Here’s a good page on it from Mesa/Boogie: https://mesaboogie.zendesk.com/hc/e...the-best-way-to-connect-speakers-or-cabinets-

 

[bodia]

And, since you're asking these types of questions, meaning a good one, make sure you DO NOT use a guitar cable to connect the amp head to the cabinet. Using a guitar cable will cause damage to the head. You need to use a speaker cable. This is a higher end cable, but a quick search at SW for speaker cables will give you other choices.

https://www.sweetwater.com/store/detail/GoldSpk03--mogami-gold-speaker-03-ts-ts-speaker-cable-3-foot

 

[Straight_six]

And, since you're asking these types of questions, meaning a good one, make sure you DO NOT use a guitar cable to connect the amp head to the cabinet. Using a guitar cable will cause damage to the head. You need to use a speaker cable. This is a higher end cable, but a quick search at SW for speaker cables will give you other choices.

https://www.sweetwater.com/store/detail/GoldSpk03--mogami-gold-speaker-03-ts-ts-speaker-cable-3-foot

And for a cheaper option I've been very happy using a Hosa skj-403, you can pick up the 3 ft cable for $8.95 on Amazon.

 

[BrianC]

Dave Friedman says its No big deal to go up or down 1 notch in mismatch...

 

[RickP]

Dave Friedman says its No big deal to go up or down 1 notch in mismatch...

His transformers may handle it. And some others may, as well. Some won’t, and I just wouldn’t take the chance because you can avoid it so easily. That’s why I keep a Z-Matcher handy. For about the cost of a middling 12” speaker, I don’t have to worry about smoking a $1000 custom transformer. Run a 16 ohm Marshall into a 2 ohm rig? No problem! Same with a 2 ohm Super Reverb into a 4x12... it’s a nice option. As Dave won’t be paying my repair bills, I stick to the “matched or higher” standard when the Z-Matcher isn’t there. Not disputing his knowledge, just stating my lack of faith to follow it.

 

[Straight_six]

His transformers may handle it. And some others may, as well. Some won’t, and I just wouldn’t take the chance because you can avoid it so easily. That’s why I keep a Z-Matcher handy. For about the cost of a middling 12” speaker, I don’t have to worry about smoking a $1000 custom transformer. Run a 16 ohm Marshall into a 2 ohm rig? No problem! Same with a 2 ohm Super Reverb into a 4x12... it’s a nice option. As Dave won’t be paying my repair bills, I stick to the “matched or higher” standard when the Z-Matcher isn’t there. Not disputing his knowledge, just stating my lack of faith to follow it.

I agree 100%. If I was buying this orange micro amp he wants I would either be getting the orange 1x8 cab for $99 that was actually designed to match it or I'd be looking for another brand of 12" cab that was 8 ohms as it appears all of the orange ones are 16 ohms.

 

[RallyFanatic]

From the manual for the amp:


Connect to a speaker cabinet rated at 8 Ohms or higher. Always use a dedicated speaker cable (not an instrument cable).

A 4 Ohm load can be connected but may cause the amplifier to overheat if used for prolonged periods at high volumes. In this case the amp should be switched off and allowed to cool.

If the Headphone jack is not in use, a suitable speaker cabinet must be connected at all times during use.

 

[PRSfanboy46]

And, since you're asking these types of questions, meaning a good one, make sure you DO NOT use a guitar cable to connect the amp head to the cabinet. Using a guitar cable will cause damage to the head. You need to use a speaker cable. This is a higher end cable, but a quick search at SW for speaker cables will give you other choices.

https://www.sweetwater.com/store/detail/GoldSpk03--mogami-gold-speaker-03-ts-ts-speaker-cable-3-foot

I already knew that speaker and guitar cables are two different beasts.

 

[PRSfanboy46]

I agree 100%. If I was buying this orange micro amp he wants I would either be getting the orange 1x8 cab for $99 that was actually designed to match it or I'd be looking for another brand of 12" cab that was 8 ohms as it appears all of the orange ones are 16 ohms.

So I can run my 8 ohm amp into my 1x12 16 ohm amp, which would pair, but I wouldn't get as much volume as say pairing a matching 16 ohm head and cab?

 

[bodia]

So I can run my 8 ohm amp into my 1x12 16 ohm amp, which would pair, but I wouldn't get as much volume as say pairing a matching 16 ohm head and cab?

Or matching 8 ohm head and 8 ohm cab.