I'm not too sure of my abilities when it comes to the CMOS crap.  How can I get some more gain outta this thing.  Look up Sunn Beta on youtube.  Mine sounds like the guy with the faded Les Paul.  I want it to sound like that PB-10 (I think that's it) preamp.  Any suggestions?

I just ran a little test.  I have no way to determine the actual level of the signal coming from the preamp output of the Ampeg, but even when the volume is cranked, it still didn't make my MXR 10 band EQ clip (odd, it does clip sometimes when I have it in the FX loop).  I've never had to turn that amp up past 3 when playing with a band either.  This is leading me to believe that it's safe.  Seems logical enough...right?

Ok...I've looked all over and every thread I've found on the internet regarding this winds up spinning wildly out of control and never seems to answer the question. I'll make this as simple as I can.

I play doom/stoner stuff.  I like a lot of bass.  I love the sound of my Ampeg VH140 but it lacks the really deep bass I want. I found a potential solution. 

guitar > ampeg...speaker out > cab
+
preamp output of Ampeg > instrument input of Sunn Concert Bass...into another cab.

So, what I'm doing here is driving one cab with the ampeg while simultaneously running the preamp out into the front end of the Sunn which I drive a 2nd cab with for that extra bass oomph.  I've only done it at low volume levels but it sounds GIGANTIC.  The question is whether or not it would be safe at higher levels when the preamp output of the Ampeg is running a bit hotter or is it going to destroy the Sunn?

preamp out > instrument input...safe?

Kind of thought so.  My Beta Lead uses all linear pots.  I just wondered if all of these were the same.  With an amp that old you never know what may have been tinkered with!

Just seems odd.  Could it be a problem?  My other 150ish watt amps are "global annihilation" loud by the time they hit 2!

I can't be completely sure but I think my amp has lost a lot of it's low end frequency response since I first got it.  That was about 12 years ago.  Great, now I feel old.  Are there any usual suspects that cause this?  My 1st guess would be caps in the power section but I'm not sure.  I just swear that it had a fatter bottom end than it does now.  It's a VH140 head BTW.  Thanks!

I noticed that late last night.  I thought that was the cap I'd be looking for but I wasn't sure.  Now where would I insert a diode or 2 to eek out a little more gain?  I'd obviously have to do it for each channel and I'd want it to be controlled by the gain pot.

I really like the overall character of it but I'd like to tighten up the bass a little bit.  I might want to cut off everything below 60hz really..it has a HUGE spike down there somewhere...scared the hell out of me when I saw my speakers flap like that!!  I'd also like to squeeze a little more gain out of it if I could.  Any ideas?  Here's the link to the schems...


http://sunn.ampage.org/site/svcmans/beta/

It's on pages 14 and 15...careful...they overlap!  Also, how would different pot values affect this circuit?  They're all 100k and that just seems odd to me.  Thanks!

I've been curious about this for a while now.  I'm a bit of a speaker junkie and I wanna know.  All I seem to be able to find is people yammering on about tube amps and worrying about frying their gear.  I already know what happens with various impedance mismatch scenarios so that's not what I'm looking for.  Here's an example...

Ampeg VH head...runs as low as 4ohm (if it goes lower please tell me!!)

Cab A - 4 speakers set up to run at 16ohm

Cab B - the SAME 4 speakers wired for 4ohm

What effect would each of these cabs have on the sound of the head?

I've heard that a a 16ohm version of a speaker will sound a bit brighter due to increased windings in the coil, and I know there's a bit less power being delivered to it.  This would be a good thing for a tube amp because you have to crank it a bit more.  Is that going to be the only difference with a solid state amp as well?  Reduced power?  If that's the case I'm going to have to rewire some things!  I don't dig the cranked up sound of a solid state amp.  Everything turns to mush...no more than 4 on the volume for me!

THANK YOU!!!!

Damn it's early...

I have a few cab I plug into here and there.  The matching Ampeg cab loaded with Eminence Legends, a peavey with Sheffield 1290's, Some home built thing that sounds fucking monstrous, and another old peavey with a uh...mixed bag of speakers!  I was just wondering if it was possible to squeeze a little more low bass out of the gain side since I usually tune fairly low.  I usually play droney doom/sluge/stoner *s!!t* with it as as we all know, doom is all about bass!  A standard low E string resonates around 80hz or something like that and since I tune down to C, B, or A (and sometimes in the G-ish range) I was just wondering if it was possible to boost those frequencies (the legends have a useable range to about 65hz) to roughly the same level.  Right now the bass control is boosting/cutting 100hz.  Oh, yes...I'm fully aware that this amp sounds WAAAAAYYYY better when it's turned up.  Right around 2 on the volume seems to be her sweet spot with the legends...and that's pretty damn loud!

You rock...I suck...period!  Thanks.  Sooo...anyone have any ideas? 

Ok...Maybe it's because I'm a noob in here, maybe it's because I'm a fool, but I can't seem to get a readable image of the preamp schematic to upload anywhere.  I get nothing but errors from this site, and when I upload it elsewhere, you can't read it.  I've tried multiple formats and no dice.  If someone wants to take a look and try to help me out, just send an e-mail to kiehano@comcast.net and I'll e-mail the whole PDF I have.  It includes all the schems for the preamp, power amps, chorus section, etc etc, along with parts list, layout diagrams, and PC trace diagrams. 

Site's not letting me post it.     It's a png file but either it's not posting at all or it tells me the file name is already being used or something like that...

Ok...found it.  For the life of me though, I don't have anywhere I can upload it.  Have an e-mail addy I can send it to?  PM me.  It's the official schem from SLM too.  It's pretty!

I'll have to find that pesky usb drive I have with the schem on it.  Should be able to have a link to it today.