That rare DSL issue with volume drop

[diesect20022000]

so my DSL100MLB is doing the infamous volume drop. red channel's thrashed. i MAY have found the culrpit picture a few posts down. I'm going to try to get some price "estimates" on having it done elsewhere but, i may just tackle it myself if i can find a safe day where my 3 year old isn't home again like today. On the bright side, i got the ground to 8 and 4 ohm jacks done,lol.

 

[jcmjmp]

Probably a bad contact or solder joint.

 

[jaek]

Could be the OT, when mine was fluctuating volumes it was cause I fried the OT but not all the way.

 

[jcmjmp]

Could be the OT, when mine was fluctuating volumes it was cause I fried the OT but not all the way.

Good point. I wonder which speaker output the OP was using. If he was using the 4 or 8 ohm, its definitely a possibility.

 

[diesect20022000]

i'd mentioned before i only own 8/4 ohm cabs. It's my only option to run in one of those unfortunately. 8 ohms is what i've used. You would think they'd fix these issues or do a recall like auto companies do. Being that these are design flaws and this is something that's been known since virtualy the begining of the DSL's and mine is a 2009 reissue. NOT kudos to Marshall in my book. Thanks for the suggestions. These aren't issues i'm rpepared to tackle personaly which means i'm probably not going to be sticking with Marshall. I love that amp but, having something that unreliable from the factory isn't going to work for me.I'm STILL waiting to hear back from Marshall on this one.

 

[jcmjmp]

I thought that it was a well known fact that the 4 and 8 ohm output jacks MUST have a proper ground added to them for proper operation.
Have the extra ground added ASAP and see how things go. Don't use the amp until that's done.

 

[diesect20022000]

I thought that it was a well known fact that the 4 and 8 ohm output jacks MUST have a proper ground added to them for proper operation.
Have the extra ground added ASAP and see how things go. Don't use the amp until that's done.

My point is it's a manufacturing flaw that should be addressed at the source. I shouldn't have to buy a new amp then imediately have it "fixed". That's just not good business imo. I realize this is a common isues which is exactly my problem. If that IS the issue then it's a manufacturing flaw that's been known since BEFORE this reissue therefore Marshall should have either remedied this at the factory or should do a recall. Even Xbox's get recalls when they're screwed at the design level etc.

 

[diesect20022000]

I'll get that done tho and thanks man, it's appreciated.

 

[jcmjmp]

Its been like that for 13 years. I don't know why they never fixed it.

 

[jaek]

Its been like that for 13 years. I don't know why they never fixed it.

It costs more money to go and change something. I mean re drawing the schematics, machining, programming, re training....

 

[diesect20022000]

It costs more money to go and change something. I mean re drawing the schematics, machining, programming, re training....

not a lot of "re training" involved. it's a simple fix technicaly. it takes a wire and solder. Either way though. i did the ground and now the channel switching latency is super delayed going back to the red channel and the problem persists. as far as the "retraining etc" goes that's bad business. auto and video game companies fix design flaws once they've been reported, they do a "recall" or they send out a voucher to have the specific issue paid for on their end once taken in. I got one such for my '98 grand prix. it has faulty battery cables that can burst into flame.

 

[jcmjmp]

not a lot of "re training" involved. it's a simple fix technicaly. it takes a wire and solder. Either way though. i did the ground and now the channel switching latency is super delayed going back to the red channel and the problem persists.

So the problem is not the ground then and adding that ground has NOTHING to do with any latency in the channel switching.

Try plugging straight into the effects loop return. If the problem persists, the problem is in the power amp, if not, its in the preamp.

 

[diesect20022000]

So the problem is not the ground then and adding that ground has NOTHING to do with any latency in the channel switching.

Try plugging straight into the effects loop return. If the problem persists, the problem is in the power amp, if not, its in the preamp.

Yeah i know the latency is elsewhere in the circuit. I'll try the power amp suggestion. One thing to note. the green channel's fine. volume and tone is there no drops so far. aside from the latency the volume and pre gain is all but non existent on the red side. I'll get back on in a few after i try your last suggestion. Thanks again, i know you don't have to sit there and help me trouble shoot my amp.

 

[diesect20022000]

power amp's loud and clear.

 

[jcmjmp]

and the volume drop only happens on the red channel?

Hmmm.... I would suspect the LDRs. I posted how to debug them on this forum. I'll have to dig that up.

 

[diesect20022000]

bummer. Thanks again man. Yeah it's all read channel and the latency's new. that just started today after i did the ground tho i knew off the cuf it had nothing to do with that. I'll do some searching as well.

 

[jcmjmp]

http://www.marshallforum.com/marshall-amps/12648-dsl-50-help-again.html#post122353

See post #38

 

[diesect20022000]

http://www.marshallforum.com/marshall-amps/12648-dsl-50-help-again.html#post122353

See post #38

wow thanks man! Yeah i have been searching this whole time,lol. I hope i can tackle this....i love my other two amps but, the DSL owns them tonaly and in versatility imo. Checking post #38 now.

 

[diesect20022000]

Now I'm having trouble finding them at Marshall,lol. Yeah it's just the red channel and the latency hasn't changed. the power amp's all good. I emailed my tech asking for a rough price estimate on this one. If it's "cheap" enough i'll have him do it. I'm too worried about doing this kind of thig around my kid tho i'm comfortable with amp surgery now. damn....i have to use another amp for now. at least they're both good amps but, man....i really love my DSL

 

[diesect20022000]

check it out. this is a pic from my main tube board.

thoughts? I'm not really sure how to replace it though so i still may go the tech route to get it done right. I'm waiting to hear back from him but, i figured i would take another look just for the hell of it since it was already open anyway. Thanks for the input. yes caps have been discharged but, i am new to this so better safe than sorry.