Amp on Fire: Marshall DSL40C

[@PsionicAudio]

Meant to say this in the video - the crucial thing here is that the EL34s had chassis-mounted sockets so all the real damage was limited to the sockets, and the parts total to repair is about $10 (not including new EL34s). If this amp had the EL34s mounted on a PCB the amp would need a new PCB. MUCH more expensive.

[@alvagoldbook2]

Precisely! Are you listening Fender? Mesa?

[@TheCyberMantis]

TRUTH. I don't like PCB-mounted sockets.

[@SirLoinMagroin]

Thanks for pointing that very important detail out. Even Marshall breaks the law on that on "certain" models. I won't say which, but I own some.

[@shoothis]

I appreciate your work . Does the same apply to the DSL 20hr Head?

[@Jonathan_Doe_]

@@alvagoldbook2 No they don’t care once their amps are outside of warranty anymore.

[@pablodana1512]

As expected, "the whole circuit will protect the fuse"

[@bradleyjames6390]

I really love the level of depth that you go into with these videos, it removes the mystery that keeps most of us too scared to want to learn about working on electronics

[@MrStevehunter33]

Denzel Caldwell stars in 'Amp On Fire' In Memphis Tennessee, a former CIA operative swears vengeance on those who committed an unspeakable act against the amplifier he was hired to protect

[@Satchmoeddie]

And it burns burns burns,..... The amp of fire..... The amp of fire. -Johnny Ash.

[@samuel_towle]

The owner must have taken it camping. Made some EL-thirty s'mores.

[@erajad]

Socket: I'm not dead! Customer: 'Ere. He says he's not dead! Lyle: Yes, he is. Socket: I'm not! Customer: He isn't? Lyle: Well, he will be soon. He's very ill. Socket: I'm getting better! Lyle: No, you're not. You'll be stone dead in a moment.

[@alvagoldbook2]

🤣

[@richardnagamitsu1582]

Haha

[@comajoebuck999]

😅😂😅😂😅😂😅

[@vincelupone]

Subscribed! Looking forward to part 2.

[@herbervalencia3401]

Between Marshall DSL20CR and DSL40CR what you prefer and why? I wait for your answer to decide wich I will buy for home and for gig sometimes in a small place (for at leats 50 people) like a coffe shop or a bar.

[@simongotlieb2560]

Yeah, nasty looking. I had a Marshall 2203X in recently that blew the filament hum circuit and there was charred mess everywhere. Cleaned up okay and I was able to replace the circuit with two 100R resistors (the board was scorched to hell). Tracked the problem down to the little hum balance pot that is the same as the bias pot. It ain't intended to cope with the current that goes through it I'm sure. Any ideas why the tubes went in this one? I'm wondering if root cause was the screen reduction resistor which may have shorted to zero resistance.

[@PsionicAudio]

Yeah, that bias trim pot is just stupid on the Marshall RIs. I bypass it with 100R 1/2Ws. Can usually do it on the little turrets there without any real difficulties. I think given that the screen R on the burned socket had already been replaced that a previous tube (or maybe the tubes in came in with given their condition) had burned the old screen R, which left some carbon in the socket. New screen R, more time and heat, and that loose lead on the resistor, either the carbon built up or that lead touched the heater connection, etc. Lots of things that could have happened. For DSL40C owners worried by this, this is a really uncommon failure mode. When I put it back together you'll see some steps I take to prevent this from ever happening again.

[@simongotlieb2560]

@@PsionicAudio I like where you are thinking there. As an amp tech, I am enjoying your videos.

[@kevinalfrey2633]

Mine keeps cutting out, I turn it back on (pop) noise and plays for a while, sound stops again

[@robertsguitarsandgear]

Great work, really looking for the root case of the short to ground and lack of fuse protection since I have this amp.

[@robotsongs]

That's what I don't understand - why didn't the fuse blow with that amount of draw?

[@shaunfogarty5744]

Good looking PCB. Big fat traces, lots of ground plane, really nice solder flow, decent component spacing, info laden silkscreen- as to whether or not it is a good circuit design. I have no idea.

[@jackpast]

My electrical instructor decades ago wanted us to say “massive fault” instead of “short circuit.” I like your “catastrophic failure!”

[@DanGower]

I’ve also had Chinese EL34’s totally wipe out sockets like that in the past. Super annoying, but luckily not too horrible of a repair.. just messy!

[@dylanjastle]

Excited to see the follow up on this one! I bought a hand wired amp from China that looks really solid inside but has some questionable tube sockets. I’ve been wondering if I should replace them before they cause issues

[@johnwilliamson467]

Belton is a fine choose in tube sockets. Worth the effort.

[@freddycookjr.2164]

WHAT JOHN SAID CERAMIC SOCKETS HAVE SHAKY PINS BELTON THE WAY TO GO

[@alvagoldbook2]

Yikes! Well, I guess running those EL34s at a lower voltage isn't going to save them if the freaking plate, screen grids and cathodes all get bridged. Well, at least the sockets weren't soldered directly to the PCB.

[@TheCyberMantis]

I hate sockets that are soldered directly to the PCB. Crappy way to build amps.

[@alvagoldbook2]

@@TheCyberMantis You can get away with it with preamp tubes, but it's bonkers to do this with power tubes.

[@roberthurless4615]

That amp, "it's seen things man". lol

[@ladyjulia4038]

This is a crazy one. Thankyou for the video friend

[@KennethDensmore]

Ive had this amp for 4 years now and had nothing but problems with it over and over again.

[@doc_matter]

Really? I love mine. Dime it every day, no problems besides v1 tube stopped working. Put a different used one in and now it's great

[@doc_matter]

What problems have you had

[@KennethDensmore]

Well within the first year I completely lost channel 2. I had to take it back to Sam Ash and wait for it to come back from repair. The following 4 months later I had volume going and paid a professional guy that supposedly worked for Knight Amps or something of that nature. He changed the tubes and biased for me (I couldn't get my multi meter to show me it correctly so I needed someomes helps) During while working he told that this amp is definitely not built like the old ones and if something were to go wrong it would ne a nightmare to service. Got it back and then id say 1 year and some change later it started dropping all the volume and I went out and purchased new power tubes and preamp tubes (that was alot of money) with the hope of changing one at a time to determine which one may have gone bad. Nope still no fix. Found the top anp repair guy in ATL (Jeff Bakos in Atlanta is apparently legendary) he had it for a month and had no help from Marshall in terms of assistance and how to lock down specifically what it was. Eventually figured out Marshall provides a 5 year parts warranty and had to take it somewhere else that had now shut down. The person there exclaimed "if Jeff bakos couldn't fix it then wow its gotta be bad"! Eventually the entire board was shipped in replaced and I basically have a new unit now. Fast foward to now a year later I lost all audio and was told its probably a fuse. Checked all the fuses they are good and found out from changing athe power tubes one by one that it was one of those. Decided to change all of them to be safe since I have all these I bought but haven't used. Been two months now and the current situation is that its making squealing noises and once again I have to stop everything amd spend time, money and energy on it. This is what's happened so far

[@robertvonherndon1921]

I ran two DSL40C'S 5 nights a week for two years with zero failures.

[@KennethDensmore]

@@robertvonherndon1921 Thats awesome and wish I could of had what you had with it.

[@sparrowhawk81]

nice princess bride reference

[@Tony_Leonardi.]

I have this amp because of your recommendation. It’s a great amp I wonder what the heck happened there?!

[@guitarmike6757]

I bought one too on his recommendation hope it’s very rare😳

[@PsionicAudio]

Should be. The circuit has no flaws that would lead to this. I’m waiting to speak to the owner - I’m wondering if he changed some fuses before bringing the amp in. Because HT or Mains should have blown.

[@russellhltn1396]

With all that partying going on, I have to wonder about the health of the output transformer.

[@acoustic61]

My nephew has a DSL40C. I hope this isn't a frequent occurence with that model.

[@PsionicAudio]

Shouldn’t be.

[@stevenferreira1289]

@@PsionicAudio are the newer dsl40cr versions better?

[@dazfarrell]

A lot of hum from some device?

[@zbaby82]

Too bad the fuses didn't blow. Badly designed fuse circuit perhaps?

[@alvagoldbook2]

Doubtful. Customer probably just kept replacing them.

[@infectionsman]

I think some nice Belton Micalex sockets would be my first choice here.

[@PsionicAudio]

That’s what burned. ;)

[@infectionsman]

@@PsionicAudio I mean for replacement, not BBQ-ing!

[@robertvonherndon1921]

I notice the board says "DSL100."

[@Mike_HuntizWet]

Same board. Difference is the Xformers and tube quantity

[@charlesclark3840]

Mostly dead? Mostly dead is slightly alive.

[@Splattle101]

Check his pockets for loose change. ;-)

[@all_invite_0hm]

I'm sure this is going to come off as a really stupid question, but what is the black plastic tool called that you're using at the beginning of the video? I've had one for a long time and use it often... but I don't know what it is or where I might've got it.

[@PsionicAudio]

It’s a plastic chopstick with one pointy end and the other end is notched to smooth small leads. Used to come with Weller pencil irons I think. Long since stopped using those irons but kept the chopsticks.

[@all_invite_0hm]

@@PsionicAudio Mystery solved. Thanks!

[@sgt.grinch3299]

Why? Fire is not good for electrical items.

[@sgt.grinch3299]

Get the funk out! Great idea.

[@geezberry8889]

34% of all used amps on the market are DSL40's