Amp Tech Thread / Ask a tech Q

[liquidsmoke]

Two 16 ohm speakers in parallel = 8 ohms.

Thank you sir!

[dunwichamps]

Two 16 ohm speakers in series = 8 ohms.

In series, speakers impedance add, so that would be 32 ohms. If you need 8 ohms, parallel them.

[rayinreverse]

Mesa's are all fixed bias, as long as you've got a good set of matched power tubes, should be OK. Then again, most noise is in the preamp tubes anyways. Good preamp tubes are more important than good power tubes, you can limp along on older power tubes, but crapped out preamp tubes are going to make the whole thing sound bad.

The butcher is fixed bias as well.

[Hemisaurus]

That should make life easier.

[VOLVO)))]

Whoa, my Droid X autocorrected me...

I need to clear that cache, yesterday, I emailed my mom and it put the word "cunt" in there, in place of "mom!"

No shit.

EDIT: As I was typing in JJ tubes to a friend, it popped in "series," after I deleted it, it popped in "parallel."

Wonky piece of shit. It just takes words you use a lot, and puts them in where it thinks you want them to go. I guess it was right about my mother.

[Ayek]

You ain't the first and you won't be the last, Mr Sunn:
http://damnyouautocorrect.com/

[VOLVO)))]

Man... poor bastards on that site. I'm turning it off.

[liquidsmoke]

From another forum, anyone agree with this?

"Series wiring- mid/upper mid and high end emphasis generally, smoother high freqs generally due to damped top end highs in the 5 to 6k range, less fizz. Additional tonal changes are slightly spongier attack and altered OD character, more complex and timbrally rich with more overtones ala the mid and top end emphasis.

Parallel wiring- low end and lower mid emphasis with more top end high sparkle or fizz, depending on the speaker and rig that can make the high end raspy or harsh to some. Low end is emphasized due to increased damping between 2 12" speakers in parallel, generallly tighter and more thump."

[moose23]

Are they talking about wiring cabs or speakers? If cabs what kind of cabs, 2x12 4x12 and how are the speakers in the cabs wired?

[VOLVO)))]

I've never noticed a goddamn thing wiring cabinets differently. I even put an RTA to one in parallel, and one in series, and one combined cab, and there wasn't hardly any difference whatsoever, nothing noticeable visibly, or aurally.

They're just different ways for electricity to flow.

[justinhedrick]

I've never noticed a goddamn thing wiring cabinets differently. I even put an RTA to one in parallel, and one in series, and one combined cab, and there wasn't hardly any difference whatsoever, nothing noticeable visibly, or aurally.

They're just different ways for electricity to flow.

this. i think that MAYBE it would sound different in a studio situation? even then only slightly. live i think all bets are off.

now that i think about it, it is just like someone saying "cabs sound different at different ohm's as well". i have never noticed a difference, but that's just me.

[VOLVO)))]

That's a total load of shit. That has to do with the efficiency of the amplifier, and if it runs differently at lower ohm loads. 16 ohms is the ~ideal~ ohm load to run an amp at, so any combination of cabs giving you an even 16 ohms (or very close) will sound different compared to four ohms, because the amp is being pushed differently.

[justinhedrick]

That's a total load of shit. That has to do with the efficiency of the amplifier, and if it runs differently at lower ohm loads. 16 ohms is the ~ideal~ ohm load to run an amp at, so any combination of cabs giving you an even 16 ohms (or very close) will sound different compared to four ohms, because the amp is being pushed differently.

so i should run my cabs at 16 ohms? hmm. interesting. i've always been a 4 ohm man myself. not sure why, that's just how they came wired.

[VOLVO)))]

~in theory~ yes.

I forget who told me this, I'm almost sure it was John McNeece, he was my amp tech until he moved, and I spent a great many hours talking to him. I feel like this is something he said. Therefore, to me, it's golden.

[Hemisaurus]

Err no, I said it, in the very first post of this thread

but it only applies to tube amps.

There's no way you can make a blanket statement about speakers in series vs. parallell, it's going to depend on the iindividual speakers, cabinets and the amp driving them. You can do complex mathematical modelling of it, or you can listen, or you can post on internet forums.

[VOLVO)))]

Sorry, dear.


~props to you~

[dunwichamps]

cant believe how many time i discuss impedance of an amp. Makes me think it should be required when buying one to watch an informational video

[liquidsmoke]

cant believe how many time i discuss impedance of an amp. Makes me think it should be required when buying one to watch an informational video

I'm more of a forgeter than a learner. I learn just enough to get my gear set up and then I try to just concentrate on the music part.

[liquidsmoke]

Are they talking about wiring cabs or speakers? If cabs what kind of cabs, 2x12 4x12 and how are the speakers in the cabs wired?

Wiring.

http://www.thegearpage.net/board/showthread.php?t=427484

[justinhedrick]

hemi, how hard is a series "splitter" speaker box to make? i have two 4 ohm cabs, want to run them together with my head . . . go!

[dunwichamps]

hemi, how hard is a series "splitter" speaker box to make? i have two 4 ohm cabs, want to run them together with my head . . . go!

I assume you mean that you amp has only one output tap?

If you want a splitter to split it into 2 output jacks, literally anyone could built that

Or do you mean you want to stack the 2 4 ohms to get 8 ohms.

That is doable 2

[justinhedrick]

i want to stack the two 4 ohm loads into an 8 ohm load.

[dunwichamps]

its going to be a little tricky,

You need to rewire the cabs so that you have an in and out jack on both. Then you run those cables back to a spitter box so you can wire them correctly.

Doable, but dirty

Unless the cabs can be rewired themselves. are they 1x12 or 2x12 or 4x12?s

[justinhedrick]

its going to be a little tricky,

You need to rewire the cabs so that you have an in and out jack on both. Then you run those cables back to a spitter box so you can wire them correctly.

Doable, but dirty

Unless the cabs can be rewired themselves. are they 1x12 or 2x12 or 4x12?s

they are 2x15s. wired to 4 ohms. so couldn't a box that makes them a series/parallel wired set? like a 4x12 cab usually is?

[dunwichamps]

You need to have access to the speaker leads without them being tied to ground in anyway. Why dont you just rewire the cabs to be 16 ohms, then // them with a box. Thats a lot easier.