Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Solid State Amplifiers => Amplifier Discussion => Topic started by: d4v1d5hu13r on May 30, 2008, 09:09:18 PM

Title: *s!!t* guys
Post by: d4v1d5hu13r on May 30, 2008, 09:09:18 PM
i plugged my pc directly into my poweramp via the effects return and now i have to crank my volume to about 9 before it 'hears' the preamp. did i mess something major up? or just the fuse?
Title: Re: *s!!t* guys
Post by: joecool85 on May 31, 2008, 07:55:21 AM
Crank the preamp to 9 before the computer hears the preamp?  Crank the preamp to 9 before the poweramp hears the guitar?  Or something else all together?
Title: Re: *s!!t* guys
Post by: J M Fahey on May 31, 2008, 10:18:06 PM
Dear "unprononunceable name" (I wonder why some kids use such meaningless nicknames): your post isn´t very clear. DID you also blow the amp´s fuse? Then you must have blown the power amp: you have an expensive trip to a service shop ahead. If not, probably you just messed the return jack contact; try a short plug-plug cable from the send jack to the return jack. You have a cheaper trip to the service shop or perhaps you *might* be able to replace it yourself. Good luck.
Title: Re: *s!!t* guys
Post by: d4v1d5hu13r on May 31, 2008, 11:27:25 PM
My first name is David = d4v1d and well it works just fine now. I guess it was a temporary problem. I can play the amp at all volumes. But no, what happened was i had to turn the preamp to 9 for the power amp to kick in. i thought i blew it, but it wasn't blown. maybe it is? but if it's blown, it shouldn't work, right? Eh, i guess i just won't play it for 2 weeks[selling it to a guy] and make sure it works before sold at at least volume of 5[for gigging purposes]. But, let's hope nothing happened.
Title: Re: *s!!t* guys
Post by: J M Fahey on May 31, 2008, 11:47:49 PM
Hi David Shuier, if I decode you correctly. I´m guessing you mean you have basically "no sound" from 0 to 9, but normal sound (no distortion, no farting) from 9 to 10? Is that so?. In that case, probably you have an internally cracked pot. To check that with minimum dissassembly, put it on 5, and solder in parallel with it (pin-for-pin) a new, known good pot, of the same value, with 3 short pieces of wire. If the "external pot" works properly, use it to replace the bad one. Good luck.
Title: Re: *s!!t* guys
Post by: casiomax on June 02, 2008, 12:50:00 AM
PC to Poweramp... PC has its own volume output settings, IMHO, output from the PC should able to drive a headphone, that should already be loud enough to poweramp input. so what went wrong? :D
Title: Re: *s!!t* guys
Post by: J M Fahey on June 02, 2008, 07:38:38 AM
Dear CASIOMAX . The output from a PC is often enough to drive fully a poweramp. A problem arises from the "strange" grounding used by their switching offline power supplies. I have seen many perfectly working PCs that light a neon screwdriver that touches their cases (their "audio ground"), besides , the audio signal is sometimes "dirty", meaning it carries "digital interference or junk" mixed in. It shouldn´t but .... often it does. I have repaired a few guitar amplifiers that blew after such a hookup. I don´t know if they became unstable and oscillated, received high frequency switching junk or the "spark" caused by the voltage difference between their grounds burst one of the power amp input transistors, buy anyway they were very dead.