DC-5 NO SOUND! HELP!!!

[blacklight_uk]

AHHH! I just plugged into my DC-5, turned the power on as normal and waited for the tubes to warm up and then flicked it off standby. No sound. I heard the normal "bump" from the speaker as i took the amp out of standby but i'm getting nothing from my guitars or by tapping on the jacks of the cables.

I'm absolutely devastated!

Has anyone got any idea of what the problem might be?

Thanks,
Josh

 

[blacklight_uk]

Actually i just tried it again - turning the amp up to full yields a tiny sound if you get right up close to the speaker. I've turned it off and unplugged it now and won't touch it till i know what's wrong. Is it the input or maybe the output transformer?

 

[Monsta-Tone]

Turn the Output volume down to normal. Try changing channels. This will tell you if it is both channels or just 1.

If it's both channels:
Try replacing V6. This is the PI tube. If it goes bad, then you will get exactly this problem.


If that doesn't work, try inserting a small instrument cable between the Send and Return of the FX loop, basically jumpering it.

If that doesn't work, try replacing each preamp tube 1 at a time with a known good tube.


If it's only 1 channel, look in your manual at the tube chart and try replacing the tubes that are associated with the channel that is not working 1 at a time with a known good one.


I usually lay the amp on it's top or on it's front when changing tubes. This lets me look into the amp and make sure that I have proper alignment for the tube pins.[/u][/b]

 

[blacklight_uk]

It's definitely both channels. I think it's about time this amp was re-tubed anyway - i bought it second hand and the guy had no idea when the tubes were last changed. I've been worried all day that it was a bad power/output transformer.

Thanks Monsta-Tone, you've given me hope!

 

[Monsta-Tone]

:lol: I haven't been able to blow a power transformer up yet, and I've tried really hard! :lol:

I rarely even see blown output transformers.

Usually a re-tube will work wonders.

I would try the FX Loop jumper before buying tubes though, just incase it's that easy!

 

[edward]

Hmmm, both channels, eh? Check the power tubes: keep your eyes on them, power it up as you maintain watch, and see that both are glowing, and that both look roughly the same hue even powered up for a few minutes. This may indicate that one of your power tubes may be bad which will knock out the entire amp, as opposed to preamp tubes (which are pretty dang tough), that would not necessarily kill both channels (although a bad V1 or V6 most certainly will render the amp DOA).

Edward

 

[blacklight_uk]

Oh my God...

Guys you are gonna wet yourselves - i found out what the problem was. Somehow i had managed to knock the speaker mute switch on! I turned it off and hey presto the boogie's back!

Ahaha! I'm such an idiot - a very VERY relieved idiot!

Thanks for all your help with this though - I'll now know what to look for if the problem ever happens properly - and i'll remember to always check that switch too!

It's funny - i've never used that switch before and i didn't go anywhere near the back of the amp last night when i was playing it last. Still...my bad!

 

[Monsta-Tone]

:lol: I forgot all about that switch. I don't think I've ever used mine.


That is great! :lol:

 

[darkmavis]

ive just got my dc10 and am having a similar problem. when i got to praccy all is good, sounds great. when we get to beer break (maybe an hour in) after the beer i flip the standby switch and i get.....virtually nothing. now i have a delay in the fx loop and if i pull the leads the sound comes back??? im all confused!!! any help would be greatly appreciated!!

 

[Monsta-Tone]

Check the cords and the battery in the delay. If you remove it from the amp and everything works, maybe try a different pedal with new cords in the loop.

That will tell you if it's the loop or not.

If it is the loop, replace V3.

 

[darkmavis]

changed de leads, and its plugged into the mains so its not that, if it is the valve, how come it only does it from standby? thanks for the heads up!

 

[Monsta-Tone]

Try a different pedal.


1/2 of V3 is the loop return circuit.

It may be that the tube went south when the amp was on standby.

You could also turn the Mix knob down and see if any of the original signal comes through. If the Loop has not been modified, then it is parallel. You should get some of the original signal flowing through if the knob is turned down.


It may be that the loop has an issue, but usually, it's something more simple.

 

[edward]

Oh my God...

Guys you are gonna wet yourselves - i found out what the problem was. Somehow i had managed to knock the speaker mute switch on! I turned it off and hey presto the boogie's back!

Ahaha! I'm such an idiot - a very VERY relieved idiot!

Thanks for all your help with this though - I'll now know what to look for if the problem ever happens properly - and i'll remember to always check that switch too!

It's funny - i've never used that switch before and i didn't go anywhere near the back of the amp last night when i was playing it last. Still...my bad!

Ya know, I was going to suggest the spkr mute switch, but then I read that you heard a faint sound from the speaker. Interesting. I would have thought that "mute" means mute. Learn something new everyday. Glad it was a simple "fix"

Edward

 

[anothersomeone]

I've done the same thing before with the speaker mute. I used to live in an apartment and had the direct out going into a home studio, then wired to some headphones because my headphone out sounded terrible. I noticed once in the apartment that sound was still coming out, but it was VERY faint.

Anyways when I finally got into my house, I was so excited to use the amp, I cranked it and NOTHING came out. I freaked until I realized it was the speaker mute...

Ahhhh, good times...

 

[blacklight_uk]

Hahaha glad i'm not the only one! :lol:

 

[BWM1130]

I used the recording out jack to send direct signal to the sound board on several jobs, but always used a transformer isolated direct box in the signal chain, the I once let the house guy convince me to use a country man DI that required phantom power from the board. This sounded okay the first time, however the next time in, the new guy used a canon to 1/4 inch adaper with no DI to isolate the output of the DC5. He claimed to have check that phantom power was turned off at the console, however that was not true. 48v dc to the output of the recording jack shorted the dual op amp that is just inside the chassis. It sits in a socket (fortunately for me).....if you review the DC5 schematic, all signal comes to an end at the op amp before the phase splitter.......if the op amp shorts- it's audio death to ground. The fix to keep gigging is to simply pop out the op amp- no harm, no foul and press on. Replace the IC at your leisure for the next recording session....... I too have fallen victim to the mute switch anxiety...........

 

[blacklight_uk]

They should call it the "mutiny switch"