first time poster, long time tech. having experience with marshall amps I am familiar with issues stemming from problematic circuit boards (i.e.-DSL/TSL etc ) however my experience regarding this model is limited. can't say I have ever been a fan of DSP. for me ,as a player/tech DSP is a deal breaker. like the dreaded nintendo game format red circle of death, once the DSP bites it you're done.  I just seek a simple answer for my customer who bought one second hand,never re-tubed. amp lost power.sounds like a badly blown speaker (speakers test good). replaced output tubes and driver tube (original outputs tested badly). preamp tubes test good. supply voltages appear to be normal.overdrive channel LED switches from red to amber to slightly different amber but no green.  clean channel button switches normal. red-orange-green.master volume button doesn't come on.sometimes if you perform factory reset all buttons function but sound is still terrible. nice clean signal going thru to pin 7 of V7.  in between V7 and phase inverter something is haywire. my money is on the DSP board but not having a flow chart ??? tried to get a signal straight into the power amp but got nothing out. any input appreciated guys.  one thing more...i get the 2 separate heater voltages. V6 is 12vdc but the other for the remaining tubes originating at the tranny, is that standard 6.3 ? didn't see it on the schematic.

So, my Marshall JVM 410c lately started making minor crackling sounds before creating a huge pop sound, and the level would be reduced until I changed the channel. This was concerning enough, and I had intended to have it checked out at my local shop, but then it began to hum and then produced the same pop sound last night. Even when I change the channel, no sound comes out now. Is there anyone who knows what's causing this? I'm not familiar with tube amplifiers, so I'm assuming this just means I need to replace a tube rather than the entire unit.

? ? ?

I read the post about the TSL 602 BIAS at this forum link:

?

should I change the two standard EL34s, and mount EL34EHs, the BIAS value is always 80mV for this model even when changing tube brands, or is this value valid only by replacing the two EL34s with the same brand?

Thank's

Ok.  A couple questions I'm sure can be answered here.

I just bought the DSL40CR less than a week ago.  It's awesome for something smaller.  Great at home amp.

However, the first clean channel is very low on volume, while if i switch to the other clean its 3 times as loud or more.  Is something wrong here?  One clean channel  can be cranked to max volume which would be the equivalent of the other clean channel at maybe a 2.

Second question, I'm hearing a lot of talk of people swapping out the speakers in these amps.  Is this always recommended?

Third question, I desire more reverb.  Is getting a pedal the answer, or another Marshall amp altogether?  Would a JVM be any better in the reverb category?

Fourth question, would getting different tubes change any of the previous concerns?  Would getting different tubes make the amp better?

Im new to valve amps, and I'm struggling to answer all these questions.

Thanks

I've got an Origin 5C, about 6 months old.  Has worked fine and is a fun little amp.  But last night I had my first issue.
Got the rig set up, with front-end fx, and also some fx in the loop. Warmed it up, then played a few bars in low power. All worked fine, so I switched to full power, and stepped away for a few minutes to let it warm up some more.
When I came back, it was still powered on (light and mild hum), but the footswitch was dead and there was zero volume. Not even cable crackle when plugging and unplugging the guitar.
I messed around with all the connections. Pulled everything and plugged in directly (also checked the instrument cable). So, guitar > cable > amp. Still no volume, and just a slight hum (very slight; it wasn't ampliyfing anything, so this was just circuit hum).
I dissambled the the thing, to check tubes and connections. Everything looked grand.
Reassembled it, and it worked fine. Played for a good 10 or 15 minutes at medium volume, and it was a charm.
But then the volume started dropping. Would come in and out. Then it dropped completely, and the footswitch went dark again.
I tried connecting an external preamp into the return (with a dummy plug in the send), but no luck. Footswitch was still dark.
Hum but no volume.
Haven't tried it yet today, but I'm expecting the same behaviour. My assumption is that there is something that goes sideways when the temperature gets up.
So, two questions:
1 - Is this a power tube issue? I haven't noticed any other problems or symptoms of bad tubes. And, like I said, it's 6 months old. Never gigged, but played loud fairly often.
2 - What's up with the footswitch? I can't find any schematics of the Origin series, and I don't care to go tracing. So, I'm not sure exactly where the FS fits into the circuit. I was wondering if that symptom might help to diagnose.
Anyway, a great little amp, but it's acting up!
Has anybody had or heard of this issue?
Thanks, friends

I have a Marshall Origin 50H, its about 7 months old and I've used it perhaps  maybe 10 times total for some pretty low volume playing and never used on anything but the lowest 5w setting. I'm using it with a proper 16 ohm Celestion cabinet and proper cables and playing for about 40yrs so know what I'm doing, well, most days that is lol! :)

Anywho,  after about 10 minutes the volume drops WAY off and I'm assuming its a power tube since the level of gain doesn't change at all,  just the volume and it gets real compressed. 

Since I've only had the amp 7 months, would the tubes be covered under warranty in any way? I would hope so due to how little I've used it, thanks for any insight.

Hello, 

I recently found a JCM900 4500 series hi-gain dual reverb in mint condition. The serial is Y38091---I know that it was made in 1990, I was just curious past the "Y" what the remaining five digits might pertain to? I was really just intrigued by reading the history of these and was wondering if mine is one of the first few produced and if it would be possible to find out what tubes and components were used on this one. Also, is it possible to get a copy of the original manual? 

Thanks for any and all help! I love my 900.

hi , can I swap out the ecc83 preamp tube in V1 for a ecc81 in a SC20H? I’m just trying to lower gain to a much cleaner sound - preferably to the origin clean . 

Any suggestions - outside of “ buy an Origin “ ;) 

thanks 

p.s REISSUE THE JMD:1 heads !

Hi. I'm having a problem with my DSL5CR. When plugged direct into the amp and switched to the Classic gain channel it works perfectly. However, when switched to the Ultra gain channel, the guitar is very faint and what can be heard is a weak-fuzzy sound. When I first noticed the problem, I thought it was a case of the tubes needing to warm up, as after 30 seconds the level would gradually increase, unfortunately the problem has got worse. Could it be the pre-amp tubes at fault? 

Thanks,
Steve

Are there instructions on how to bias Origin 50 power tubes? A schematic?

I have a DSL40C i purchased in September. After a few weeks it started to emmit an arcing sound when in standby. I returned it to the supplier who found nothing wrong. It has been ok since except for a  wooshing sound when it is first turned on that stays at the same volume even if I turn the volume up but slowly dissapears over time (I assumed this was just the valves heating up and settling and happened in both normal and low power modes) Today it started the arcing again and it would not turn the volume off in standby mode, then standby mode started working correctly and now if i put the amp in low power mode the volume starts decreasing and eventually disappears after about 10 seconds. Normal power mode seems to be OK though. Does this point to defective tubes already?

I purchased a new DSL40CR  a few months ago. I think I need to replace some of the tubes/valves. The product is still under original manufacturer warranty, so I would like to take it to someone qualified to work on Marhsall amps, rather than change them myself. I have never owned a brand new amp before, so I don't want to void any warranty. How can I locate a proper amp technician in my area (Buffalo, NY) to help me with this? Appreciate any help. Thanks .

Dave

Hello,

can I use my JTM60 speaker with a Marshall Origin 20H Head?

Also, my JTM60 has suffered some damage when my nephew tried to power on the amplifier, she cranked everything up but didn't succed, when I got home I didn't noticed it was all cranked up and powered it, it blew tubes and some more, I had it repaired but it didn't get back to the same sound as before... I'd like to have it checked by qualified personnel, can you indicate someone in Italy, please?

Thanks a lot,

Marco

Got myself what i thought could be the greatest idea of an amp,Origin 20h.  looks awesome , plenty of clean , Too much clean , i can t seem to get gain and dirt out of it , i tried with Humbuckers seymour"s Pearly gates, and Aph-1 ( little gain but just to mention )  and with my strat with ssl-1 and ssl-5 it was cleaner than my fender Blues junior  ??  is there a way i can get it to growl more , change tubes? what should i put in  to get it the meanest ? i reallythought i could drive it better , oh yes and the treble, mid , bass, no big difference there also .  Not sure i want to invest to much in case there is no significative results.  what should i do to get real gainy dirt, please don t answer me to by a jcm900. cheers

Somewhere on the internet it was mentioned that replacing the power tube of a DSL5CR does not require to re-bias as the DSL5CR is a "self bias" system.
Can anyone confirm this?

Other question what would be the best brand to have for my DSL5CR power tube?

Hi all, i’m looking to buy a new marshall sc20c jcm800 tube amp and get payday loans 24/7 and it doesn’t have a headphone jack . Could i plug headphones into the jack called “DI OUT” or not and what does this do?

Hi,

I have a Marshall 9200 poweramp (Dual mono-bloc) that I am having problems with. Channel A works fine, but when I turn on Channel B, I get no output, but rather I get this low pitched buzzing sound that becomes louder and louder. (Both channels work independently of each other, as in Channel A runs 4 6L6GC tubes and Channel B runs another 4 tubes)

Also, Channel B's tubes glow blue when it is turned on. (I never turn Channel B longer than 30 seconds after that buzzing sound starts) I was wondering whether it was a blown tube or whether it is something more sinister at work, i.e. a blown transformer.

FYI, the amp doesn't trip the fuse, but rather the tubes just immediately glow blue, like the gas in the tubes is on fire or something.

Thanks for your help guys.

darmowe dzwonki na telefon

Hi,

Have a few questions about attenuator usage with SC20H amp.

1. Do I need two attenuators? My cabinet has two speakers (8 Ohm each), and SC20H has two separate outputs for each speaker, so does it mean I have to buy two attenuators, one for each speaker? I didn't manage to find SC20H schematics, so I'm not sure if those two amp outputs are connected in parallel internally, and I can just use one attenuator.

2. Do I need attenuator(s) at all? I want to run the amp with overdriven tubes, thus I have to set max level, right? Consultant at my local store told me it's enough to reduce "Master" volume, and EL34 will still be overdriven, if I set "Pre-amp" volume to max. But folks at Marshall forum say that it's still better to use attenuator, even in 5W mode. Again, I don't have SC20H schematic, so it's hard to tell who is right.

3. What if my cabinet only have one 4 Ohm input (2 x 8 Ohm speakers inside)? Is it enough to connect it to the amp with only one cable? Or I have to rework my cabinet to have two different inputs (separate input for each speaker)?

Thanks!

Hello,

Where I can buy the Marshall Dsl40c's fuses?

I've had a hard time finding them. My Marshall went silent and I replaced all the tubes.

Running out of ideas.

thanks

alexsunny

Hello,

I am a recent ower of a Marshall Origin 20, which I got in July. I've really enjoyed the amp until I plugged in last night and got out absolutely no sound out of it. I couldn't figure out why, as nothing as happened to it and it worked fine two days ago. I took it apart to do some trouble shooting and found that when I have all the knobs max'd and output on 20 watts, I can hear a whisper of my guitar signal (nicely saturated, presumably by the preamp tubes) through the speaker. This sound is affected by all of the knobs. However, if I plug my guitar directly into the return of the effects loop, and activate the effects loop I get no sound whatsoever; no guitar, no hum, nothing. Because of this, I'm sure my speaker is not the problem. These things led me to think it was a power amp section issue, so I went down and purchased a new set of matched EL34's, threw them in there, and nothing changed. I'd really like to know if there's anything I can do to fix this, because this amp is not even a year old and I should not be having these kinds of problems with completely normal bedroom use.

Thanks,

Alex