[earplay]

On Michael Mardis' old tripath site, he has this picture and text.


In the power section we see some filtering, notably the LC filter. Nice idea. The gold rectangle is the power switch, the diode is probably for reverse polarity protection.

Later he suggests that to improve performance "... remove the reverse polarity protection diode. That will give a 0.6V boost, can't hurt." I assume he does not mean the LED.

Having time and despite having little sense and skill when it comes to things electronic, I dove right in to my modified Super T and removed the black and silver diode (the thing to the right of the power switch with "12" on it) and replaced it with a wire connection. THE THING WENT DEAD. When I re-installed the diode, life returned to the Super T.

What did I do wrong? Anybody?

[richidoo]

Did he say to replace the diode, or just remove it? 

He goes by 'panomaniac' here on AC, so you can PM him. 

[mgalusha]

If it's in series for reverse protection, you would have to remove it and put a jumper in it's place. Note that if you mistakenly connect power in the wrong polarity, the diode is no longer there to save your amp.

[Steve]

Would you happen to have a schematic you can post Earplay?

Cheers.

[earplay]

Steve, no, I don't and I can't find one.

Thank you one and all for the assistance.

This thing is a Sonic Impact Super T-Amp and no longer manufactured. I've made several modifications suggested by panomaniac and put the whole thing into a wood cigar box. I just love the sound it produces.

As I said, now that I got the thing working again, I feel lucky at that and I had better leave well-enough alone because my soldering skills are affected by nerve damage. In other words, I'm a crappy solderer. Any time I undertake a solder slinging operation, I do so with a lot of introspection, but never quite enough, it seems. I can no longer attribute that to the exuberance of youth because I'm too old. I guess it's just stubbornness... or stupidity.

Having spent some years on this forum, I recognize you who responded to my post. To me, it's like I have ascended into a higher plane of electronicism. YOU. ARE. GODS! I am not worthy!  (see Wayne's World or www.youtube.com/watch?v=Vh78T--ZUxY) 

[richidoo]

You have the balls to mod your commercial gear. You tried and failed. Now try again until you succeed! Use a voltmeter/ohm meter to check your work and figure out (with Lab advice) what is wrong. You can do it, earplay! Don't give up. 

Here is Michael's mod page. http://www.michael.mardis.com/sonic/super.htm

[Davey]

earplay,

Hmmmmm.

Put your DC voltmeter across that diode when it's operating and see what it reads.

Dave.

[earplay]

Okay, but there's this post I just posted in the Trading Post:
"CRAP!!! I'm in the process of setting up my system after a move and a long time in storage. I just now discovered that my modified, sweet-sounding and now too-expensive-for-me-to-replace Cary pre-amp is putting on a light show at a solder joint. I cannot easily access the joint and my soldering skills are lousy. I gotta find a competent local repair person and get this sorted out before I make any other moves."

(Two hours later) I found a local repair shop that had good reviews and just returned from taking them my pre-amp to see what they could do. Can anyone tell me if $175 as a flat rate just to get started on fixing my pre-amp is on the high side. It seems pricey to me.

In addition, I'll have to buy yet another volt meter because that, too, disappeared in the move. I think this is an "ex-significant other" issue. UGH!

On top of that, balls or lack thereof is not the impediment. Richidoo, I've seen enough mountain tops, deep jungles and ocean bottoms at night that I feel comfy with my balls (well, these shorts are a little tight, but...). I just don't want to FU something that is working well enough... this is only to say that I'll have to put this off til I get another volt meter. I guess you win. I still have no sense!

So, is $175 steep as a starting price before any work is done? I think that includes the first hour of labor.

[richidoo]

That's steep. $75/hr is typical for electronic repair. PM sent..

[earplay]

Okay, now I want to thank everyone for holding my hand. The Cary pre is fixed. I tracked down the problem to the pcb. I thought that there was a bad solder  joint, but the joint was good. There was a short between adjacent traces in the pcb. I clipped the leads to the diodes connected to the affected traces. Then I unsoldered the wires running into the affected traces and attached them directly to the diodes' leads, applied power and voila, no sparks, no light show. The pre amp works!

This now affects every other move I was making in a rush to get this system going. For instance, I will now be content with my "personalized" Super T amp as I will be able to push a power amp with the fixed pre. So now I can look for something tubish that puts out ten or twelve watts.

Again, thanks to everyone.