Help Wiring a Replacement Potentiometer for Sonic T

[Lostcause]

Originally posted by jwb009
I just saw that the 'stealth' version is up and i'd like to try it...however I have already done the 'Version 1' mod, removing R1 and R2.

So my question is can I still do the stealth version somehow, or will I need to put R1 and R2 back in (I already threw em away, or lost em)? Thanks

I suppose you just need to use the resistors you jumped in with?
Un-solder from the caps and solder that end to the board to complete the circuit as it was? The traces/leads will increase the chance of RF pick-up but it may be OK?

[orpheus]

Since this thread has kind of turned into a modding thread on the t-amp, and someone brought it up above...

How can I lower the DC offset of the T-amp? I have a stock amp now, and the right channel is around 150mv and the left is around 45mv DC. Not a big deal with speakers, but I want to use the t-amp with my AKGK1000's, and I'm a bit concerned about exposing them to that much DC.

Have any of the mods above lowered the DC offset? What modification could I do to lower the DC offset?

Thanks for your help.
-Aaron.

[Diomedian]

Forgive me if this is a stupid question, but DEQ+TheEnd, have you got the new 2.2uF cap in backwards in your schematic?

Jeremy

[dijon]

ok, so i got this t-amp and hooked it up and liked it. check. now i want to mod it so i search and find panomaniac's/audio1sts cool stealth mod. i picked it because it had the best drawing - honestly, no other reason.

so, i get myself some radioshack goodies, am already decent with a soldering iron just from fixing broken guitar pedals etc..and set to work.

so here are my questions. the capacitor number /value ratings confuse the bejeezus out of me. at some point i ordered some blackgate 16v2200uf caps. must have been drinking and ebaying again... anyway, i got those. then i see 2,2uf auricaps on audio1sts pic...now (and here's where i protect my head with both arms) are these the same value? if not will i screw things up if i use my blackgates? should i just order those auricaps i see in the picture?

also, i don't have a pot - yet - so i was thinking of running this thing wide open and letting my squeezebox do the volume control - which is what i do now with the unmodded t-amp. would i just go straight from the audioinput -> cap -> board following basically the same wiring?

and finally (i hope i'm not clogging this forum..seemed to me we were discussing the stealth mod...but i could be wrong) i didn't see in audio1sts picture that the speakers had the resistor thing wired between them like the original - is that on purpose or just out of scope of the mod? i went ahead and wired them on.

so i'm hoping that without any understanding whatsoever of the intricacies of electroengineering - i can just do some basic soldering of gizmos and doodads and enjoy some phatter bass...here's hoping!

--dij

[Diomedian]

Hi Dijon,

Regarding those Blackgates, they are rated much much too high. The "uF" rating is more or less how much power they can store, so a 2200uF cap stores 1000 times as much as a 2.2uF cap. From what I can tell, if you used those Blackgates in place of a 2.2uF, you would blow up your speakers (someone correct me if I'm wrong). People have been reporting nasty turn-on thumps when using even 4.7uF caps, so...
As for the Auricaps, it needn't be them in particular - any decent 2.2uF cap should work. Personally, I'm using a Blackgate PK series cap (but if you use a polarized cap, make sure to point the "-" end towards the source - I wired mine up backwards with very strange results).
When it comes to voltage rating, you say you have 16V caps. That means that is the maximum voltage it is safe to apply to that cap. So if the circuit will see 10V, you can use a 16V cap. You could also use a 50V or a 100V no problem - it would just be a waste, as they tend to be more expensive. Usually though, when you expect to see some voltage X, you would use a cap that is rated a fair bit greater than X for safety's sake.

You're right about the volume pot. I'm not sure what a squeezebox is, but if it has a volume control, yes, you can just run it right into the T-Amp. It would go: input->cap->board, just as you said.

I'm not sure about the "resistor thing" you're talking about between the speakers. Do you mean the red 0.1uF film cap? If so, leave it in. :-)

Jeremy

[dijon]

oops, my bad. those things on the speakers are capacitors..and i actually knew that one! as i said, i already connected them, so that's good to know, i'll leave them be.

as an aside the squeezebox is a digital audio player you can read about it at www.slimdevices.com it's my favorite music toy in the world..i have 4 of them..hence the need for all these tiny amps

so thanks diomedian for stopping me from putting those 2200uf caps in my squeezebox. i guess i'll try and get some 2.2uf - any online places that will sell me just 2 of them?

one final question regarding the pot if i decide to use one - my local radioshack only has single gang pots - no way these could be used right? the whole stereo thing?

man, i'm in deep water!

dijon

[Diomedian]

Sure you can get just two caps - The Parts Connexion sells nice high quality stuff:
http://www.partsconnexion.com/
(They're in Canada, but they sell in $US)

Also, Digikey sells just about everything except the "boutique" kind of parts that the Parts Connexion does:
http://www.digikey.com/

As for the pot, you _could use two mono pots, but then you'd have a tough time balancing the channels - it would just be a pain adjusting the volume twice. Both the Parts Connexion and Digikey sell a variety of audio pots - you just need to know which one you want. Digikey sells an overwhelming variety of everything. (If you want it, they probably have it, as long as you know what it's called :-)

Jeremy

[dijon]

ok, after all that, got my parts etc..followed audio1sts diagram, solder all looks good (to me anyway), flipped the switch...zip. should i just scrap and assume i botched something (most likely removing and bridging those tiny caps). if anyone could tell me what to do with my circuit tester (like what setting, where to put the probes etc) i might be able to at least learn something from this. the good news is, i'm fired up enough to get another one of these things and just try again.

anyway, thanks in advance!

dijon

ps. there's power to the board as the led lights up and i get some clicks and pops as i push wires around but that's about it.

[audio1st]

Originally posted by dijon
ok, after all that, got my parts etc..followed audio1sts diagram, solder all looks good (to me anyway), flipped the switch...zip. should i just scrap and assume i botched something (most likely removing and bridging those tiny caps). if anyone could tell me what to do with my circuit tester (like what setting, where to put the probes etc) i might be able to at least learn something from this. the good news is, i'm fired up enough to get another one of these things and just try again.

anyway, thanks in advance!

dijon

ps. there's power to the board as the led lights up and i get some clicks and pops as i push wires around but that's about it.

Hi Dijon,
sorry to hear of your problem, any chance of some photos?
Did you remove R01 & R02 ? Seems strange that both channels aren't working..
You didn't need to remove caps C3 & C4, just blob, ( technical term ) some solder over them would have worked.

Your 2200uf Black Gates will be great for the power supply..

I don't think you could have done any damage and hope it is repairable. More info needed to help..

Barry.

[motherone]

Pictures of the mods would definitely help, too.