4 and 2ohms TUBE AMP to 8ohms cab??

bichibreaker · #1 10-19-2010, 10:41 AM

Is there any way to transforma 4ohms amp (like svtcl, vr, etc) to can match with a 8ohms cab (svt410he)??

I can't get a hlf in my country.
and i wont cary two cabs on my own

Thank you

Maltross · #2 10-19-2010, 10:47 AM

You can run it together. Might be losing some power, but resistance of the amp won't cause a fire or anything. If you ran an 8ohm head into a 4ohm cab then you would be in trouble.

In my case I have a 2ohm sunn head that doesn't push out enough watts at 8ohms. I had to buy a 4ohm cab to solve my problem.

You also have a choice of re-wiring, but that could be a very difficult process depending on the cabinet.

JimmyM · #3 10-19-2010, 10:50 AM

no there's not. sorry.

BigOldHarry · #4 10-19-2010, 10:51 AM

good lord. Where's the sticky for this!?!?!

Selta · #5 10-19-2010, 10:56 AM

Quote:

Originally Posted by Maltross

You can run it together. Might be losing some power, but resistance of the amp won't cause a fire or anything. If you ran an 8ohm head into a 4ohm cab then you would be in trouble.

In my case I have a 2ohm sunn head that doesn't push out enough watts at 8ohms. I had to buy a 4ohm cab to solve my problem.

You also have a choice of re-wiring, but that could be a very difficult process depending on the cabinet.

Re-read the OP please...

Quote:

Originally Posted by JimmyM

no there's not. sorry.

+1

Quote:

Originally Posted by BigOldHarry

good lord. Where's the sticky for this!?!?!

+1000

Selta · #6 10-19-2010, 11:02 AM

At the risk of having someone come in and pull a Brad on me..

Will it work? Yes. Will it sound good? Only you can answer that. Are you risking the amplifier in doing so? YES!

bichibreaker · #7 10-19-2010, 11:19 AM

ISN'T THERE ANY WAY (CHANGING TRANSFORMERS OR SOMETHING IN THE AMP) TO CREATE A 8OHMS OUTPUT?

BassmanPaul · #8 10-19-2010, 11:30 AM

Not cheaply no.

T-Bird · #9 10-19-2010, 11:31 AM

Hi.

Quote:

Originally Posted by bichibreaker

ISN'T THERE ANY WAY (CHANGING TRANSFORMERS OR SOMETHING IN THE AMP) TO CREATE A 8OHMS OUTPUT?

You can change the output transformer, OT for short, but it's not worth it.

You can however re-wire the cab or replace the speakers to get a different impedance. What the end impedance will be, depends of the individual impedances of the speakers.

Replacing the speakers will probably be harder and more expensive to do as the speakers have to match the box.

Regards
Sam

Selta · #10 10-19-2010, 11:35 AM

Quote:

Originally Posted by bichibreaker

ISN'T THERE ANY WAY (CHANGING TRANSFORMERS OR SOMETHING IN THE AMP) TO CREATE A 8OHMS OUTPUT?

Woah, hey now... no need to yell.

I don't know if the SVT trannies have 8 ohm taps on them at all. Even if they did, it's not such a simple process to just plug it in and make it go. Given the general feeling of lack of EE knowledge I get from your posts, you'd have to take it to a tech to have done - you'd be looking at a minimum of a $50 bench fee just to have it looked over, plus whatever their hourly rate is and any parts they want to use. It wont be cheap to do.

I don't know how the SVT410HE is wired, so I can't guess if it can be re-wired to 4 or 2 ohm. I THINK they are 32 ohm speakers in parallel though - if that's accurate, you're pretty much stuck.

It'd be much more helpful to know exactly which head you have and if you are intending to attempt to force the issue with the SVT410HE.

JimmyM · #11 10-19-2010, 11:45 AM

they do not have an 8 ohm tap, only 4 and 2. yes, i suppose you could get a custom tranny made but there will be consequences, either in outrageous cost or trouble adapting the rest of the amp to it. the trannies don't exist in a vacuum.

have i run an svt with an 8 ohm load before? has it been fine? yes and yes. however, i play at very low volumes and it's not good for the amp to be played at higher volumes at 8 ohms. it will stress the tubes and tranny and can result in eventual early failure. so my advice if you want an 8 ohm amp...don't get an svt.

bichibreaker · #12 10-19-2010, 12:34 PM

[quote=Ray Salamon;9866632]
[quote=JimmyM;9866690]
Thank you
I don't speak english very well so...i'll try to explain you the situation.
I live in Argentina
My actual rig is an svt4pro + svt410hen
I've got a friend living in the us who can (maybe) bring me a head (cheaper than anyone i can buy in my country).

The thing is that i've got this cab and i was trying to find the way to use a tube ampeg head with my cab. (i would obviously take it to a tech to do what i need)

The other option is the v4 or v4b or v4bh buy i don't know if the power would be enough.

bichibreaker · #13 10-19-2010, 12:34 PM

[quote=Ray Salamon;9866632]
[quote=JimmyM;9866690]
Thank you
I don't speak english very well so...i'll try to explain you the situation.
I live in Argentina
My actual rig is a svt4pro + svt410hen
I've got a friend living in the us who can (maybe) bring me a head (cheaper than anyone i can buy in my country).

The thing is that i've got this cab and i was trying to find the way to use a tube ampeg head with my cab. (i would obviously take it to a tech to do what i need)

The other option is the v4 or v4b or v4bh buy i don't know if the power would be enough.

JimmyM · #14 10-19-2010, 12:41 PM

only you can answer that. used to have a v4b and with an 810 i never wanted for volume. however, i never set out to kill babies with volume. if you're a baby killer

, you may find it inadequate. unfortunately, them's the breaks with the svt tuber.

BassmanPaul · #15 10-19-2010, 12:42 PM

You can change the impedance seen by the amp using an impedance matching autotransformer. This will have to be able to handle the full output capability of your amp. That alone makes it big, heavy and expensive. There's more to go wrong and in the end may well be more expensive than selling the cab you have and buying one suitable for a tube amp.

okcrum · #16 10-19-2010, 12:52 PM

Can the SVT410HE be rewired to 2 ohms?

Selta · #17 10-19-2010, 12:53 PM

Quote:

Originally Posted by okcrum

Can the SVT410HE be rewired to 2 ohms?

I don't think so. I'm 90% sure it's 4x 32ohm speakers in parallel. You'd need new drivers to get to 2 ohms, which I would heavily advise against.

Destructobot · #18 10-19-2010, 02:29 PM

Quote:

Originally Posted by Ray Salamon

You'd need new drivers to get to 2 ohms, which I would heavily advise against.

Why? Doesn't seem like a bad idea to me. I can't imagine Ampeg put a ton of engineering into a bass reflex, direct radiating 4x10. There's plenty of speakers out there that'll sound just fine in that box.

aborgman · #19 10-19-2010, 02:31 PM

Quote:

Originally Posted by JimmyM

no there's not. sorry.

Yeah, there is - but it'll be expensive.

You need a 2:1 audio transformer that can handle whatever power level and voltage is necessary for the amp.

Selta · #20 10-19-2010, 02:36 PM

Quote:

Originally Posted by Destructobot

Why? Doesn't seem like a bad idea to me. I can't imagine Ampeg put a ton of engineering into a bass reflex, direct radiating 4x10. There's plenty of speakers out there that'll sound just fine in that box.

I guess if the OP wants to find out what speakers to put into that cab and buy them, he certainly can. Not a route I'd take myself though, at all, and I can do the math easily enough to figure out what speakers I'd want in it on my own

. He's going to have to find/figure out every spec of that cab, which if you don't know what you're doing, isn't a simple task.