Help! I think I f**ked something up...

Trem Abuser · Post by **Trem Abuser** » Wed Apr 20, 2005 4:14 am

Flames1950 wrote:Jesus Christ gentlemen, quitcher' yappin' and tell me straight up Trem -- did you add the jumper between pins 3 and 8 on the phase inverter 12AX7 and did it get us sound?????

Sorry Flames, lost focus there. I was at work, and I had paddling practice tonight so I wouldn't be home until most of you guys had gone to sleep.

So I added the jumper and there is the sound, full, loud and wonderful. Its late, so I do not get much time to play tonight to fully try it out.

However, I am relieved. It works.

Guys - many thanks to all of you who helped and gave instructions, advice and tips. It goes without saying that I could not have done it without your help. I don't want to get into naming names lest I leave someone out, so I'll leave my heartfelt thanks in general and vague terms. Mahalos.

Flames1950 · Post by **Flames1950** » Wed Apr 20, 2005 8:37 am

However, I am relieved. It works.

Aaaaaah.......peace..........and what a long strange trip it's been.

Trem Abuser · Post by **Trem Abuser** » Wed Apr 20, 2005 3:15 pm

Peace back at you

.

Yes, the doozy project undertaken by the green amp-rookie, the obvious mistakes, etc.

Now, the question is do I put the amp in the head enclosure or do I solicit forum opinions on tweaking it before doing so?

Flames1950 · Post by **Flames1950** » Wed Apr 20, 2005 7:06 pm

Uh oh, tweaking. You thought getting it running took a while.

What needs tweaking so far?

Trem Abuser · Post by **Trem Abuser** » Wed Apr 20, 2005 8:16 pm

OK, "tweaking" may have been a strong word. I guess I should have said "adjustments" - what I was referring to were things like swapping the cap on the particular pot which the instructions say to swap until you find the "just right" value.

In short, do I mess around with some stuff like changing these caps, or do I put the amp back in the head box and just play it for a while? I haven't played it long enough to really determine if anything needs tweaking.

Billy Batz · Post by **Billy Batz** » Wed Apr 20, 2005 8:18 pm

Unless your taking it out to play soon dont put it in the cab. Just play with it for a while and try the other bright cap values and see what floats your boat.

Rickfox · Post by **Rickfox** » Thu Apr 21, 2005 12:16 am

Hey Scott!! What a wonderful feeling when you hear that monster come to life!! Many of us on the board can remember the day?!!!!! Congrats!!!!!
Rick

Dax · Post by **Dax** » Thu Apr 21, 2005 12:50 am

I Remember!! I was so close!! I had the diodes backwards, Caps backwards and inputs wired wrong. Gnugear and the fellas set me straight and it was like fine wine!! Frickin' loud powerful wine!!!!

Dax

Trem Abuser · Post by **Trem Abuser** » Thu Apr 21, 2005 3:38 pm

Yep, all the time of the guys who pitched in to help me is truly appreciated. This board is really great to help out guys in my situation (up the creek sans paddle).

Now its figuring the thing out (tough as I can't play it anywhere near "loud" in my apartment, and the hotplate seems to squash the tone at near-load attenuation). Definitely there is tone there, but I'm getting a squeal at certain times. Its not there all the time, and I haven't figured out all of the factors which cause it to squeal. Clearly cranking it contributes to squealing, but also the proximity of the guitar to the amp and cab.

What is amazing to me is how responsive the amp is to the guitar's volume knob. Even with the amp's volumes very low, if I turn the guitar's volume all the way up it is fricken' loud.

Also, I think I'm going to melt my output transformer with this thing. When I have the amp really cranked (but heavily attenuated so I can hear myself think), I can hear a "sizzling" sound coming from the amp, in tune with the (attenuated) sound coming out of the speakers. And the output transformer gets pretty hot as well. Since the OT is a holdover from the 6L6 days of 30 watt output, I may well be beyond its capability to handle the output.

Billy Batz · Post by **Billy Batz** » Thu Apr 21, 2005 4:59 pm

Thats normal with any amp. Even when I have the master turned down low on my SLO I can hear that but when your using an attenuator you can always hear that. Ive heard records where engineers mic that sound for a crazy effect.

Trem Abuser · Post by **Trem Abuser** » Mon Apr 25, 2005 4:01 am

Billy Batz wrote:Unless your taking it out to play soon dont put it in the cab. Just play with it for a while and try the other bright cap values and see what floats your boat.

How does the bright cap value affect the tone? Does it have anything to do with the amp squealing?

Flames1950 · Post by **Flames1950** » Mon Apr 25, 2005 7:45 am

It may help accentuate the squealing, but the usual cause of squealing lies in exactly how the wires are laid out -- some wires just aren't good neighbors. The classic example is having the purple wire going to the Presence control too close to the wires going to the other tone controls, they should be seperated.
Yours is going to be a unique case since it's built from a different amp, you'll have to guess from pictures of a stock 50 watt Marshall chassis which way wires might need to go to get rid of the squeal.

Trem Abuser · Post by **Trem Abuser** » Mon Apr 25, 2005 2:17 pm

It really doesn't squeal that much, but if I'm sitting one foot away from the amp with the amp cranked, I can get some squealing.

Is it sort of a process of elimination? I did my best at keeping the presence wire away from the other tone controls, try to cross the heater wires at 90 degrees, etc., as people advised.

Flames1950 · Post by **Flames1950** » Mon Apr 25, 2005 2:26 pm

Is that with the guitar volume on or off? I'd never stand a foot away from an amp with my guitar and amp both cranked; too many clashing magnetic fields that are gonna cause major feedback issues.

Trem Abuser · Post by **Trem Abuser** » Mon Apr 25, 2005 3:10 pm

Its when I'm adjusting the volume or whatever on the amp. (Actually sitting, but that's besides the point).

Its nothing unmanageable, I just want to make sure its working right.