A problem with my YJM100.

[Stefan_E]

My YJM100 suddenly developed a problem. The first "channel" sounds thin, fizzy and very low volume. The second two inputs sounds as usual, no problem there. I switched V1 preamp tube for one that I know works, but the problem is still there.

I'm going to leave it at a local amp tech, but I was wondering if anyone has a clue if this is one of the known issues with this amp.

Basically I need reassurance
Will the patient live?

 

[Creach]

Maybe a trouble on the booster, is the sound ok on the channel 1 low input?

Here some details : https://www.marshallforum.com/threads/yjm-question-for-santiago.28564/

 

[V-man]

Fingers crossed for you. I just bought one and returned it the next day discovering all the nightmares the amp had.

as above, Ch1 Hi sensitivity is the only input that actuates all the on board crap (Gate/Boost) and that’s where the IC 5 nightmare begins- you can’t even replace the board… you have to send for a repair kit and hope it works. Fuck that amp. Sorry for your trouble.

 

[marshallmellowed]

My YJM100 suddenly developed a problem. The first "channel" sounds thin, fizzy and very low volume. The second two inputs sounds as usual, no problem there. I switched V1 preamp tube for one that I know works, but the problem is still there.

I'm going to leave it at a local amp tech, but I was wondering if anyone has a clue if this is one of the known issues with this amp.

Basically I need reassurance
Will the patient live?

Yes, is the issue present just with the boost engaged, or even without?

 

[Stefan_E]

Thanks for taking the time to reply!

The problem is present on both hi and lo input on channel one, while there is no problem at all on either of the channel two inputs.

I haven't tried turning the boost off and on, I have barely used the boost. I will try it more thoroughly when I get back home.

 

[V-man]

One thing to check is whether the gate (still) works. When the gate is engaged, the knob in back should act as a threshold (sensitivity where the gate kicks in and kills the amp signal in silence). If instead of triggering the gate, the knob simply increases/decreases volume or gain, you have a problem on your hands (IC5). Do this with the boost on and off. The one encouraging sign is it’s problematic with the lo jack too, but I don’t know how whether that gets you out of the woods.

 

[Stefan_E]

One thing to check is whether the gate (still) works. When the gate is engaged, the knob in back should act as a threshold (sensitivity where the gate kicks in and kills the amp signal in silence). If instead of triggering the gate, the knob simply increases/decreases volume or gain, you have a problem on your hands (IC5). Do this with the boost on and off. The one encouraging sign is it’s problematic with the lo jack too, but I don’t know how whether that gets you out of the woods.

The problem is only on Input I. The gates acts only as increase/decrease on volume/gain.

SO, is there a way to fix the IC5-issue?

 

[Audrix]

I had a YJM 100
Wonderful specs !!!
.... but too much repairs
The technician told me that the conception is very ambitious but high voltage and low voltage signals so near will make problems again...
So I sold it after repair and bought a classical JCM800 2203

I have a "modern" JVM410 C without problems

 

[V-man]

The problem is only on Input I. The gates acts only as increase/decrease on volume/gain.

SO, is there a way to fix the IC5-issue?

The amplifier essentially IS input 1. Everything YJM (boost/loop) is tied to that channel input

Do some searching (google, MF, YouTube). I came across a video of a guy throwing the kitchen sink at his including the IC5 (which did not work for him).

Regarding the IC5, (as you will find in your search) there is no replacement board, and (years ago) Marshall offered a “Service Kit” (repair kit).

So, you are going to have to get lucky scoring one of these with Marshall/elsewhere, you are going to have to get lucky that you/your tech does not screw up using the repair kit and last, you are going to have to get lucky that this service kit (acquired and successfully used) addresses the problem/you don’t have other issues running parallel to this one. Fun times, eh?

 

[Stefan_E]

The amplifier essentially IS input 1. Everything YJM (boost/loop) is tied to that channel input

Do some searching (google, MF, YouTube). I came across a video of a guy throwing the kitchen sink at his including the IC5 (which did not work for him).

Regarding the IC5, (as you will find in your search) there is no replacement board, and (years ago) Marshall offered a “Service Kit” (repair kit).

So, you are going to have to get lucky scoring one of these with Marshall/elsewhere, you are going to have to get lucky that you/your tech does not screw up using the repair kit and last, you are going to have to get lucky that this service kit (acquired and successfully used) addresses the problem/you don’t have other issues running parallel to this one. Fun times, eh?

Thanks, yes, just what I needed, haha

I found the PDF from Marshall with info about what could solve the problem, and I think the SMD is still available. Plus I think I have found someone who might be able to help me.

I'm still hopeful.

 

[V-man]

Good luck. I just glared at the fucking YJM I returned at the store this weekend.

 

[Stefan_E]

Thanks, the guy said it was doable, so I really really hope it is. It sounds so amazing when it works.

 

[Adrian R]

One thing to check is whether the gate (still) works. When the gate is engaged, the knob in back should act as a threshold (sensitivity where the gate kicks in and kills the amp signal in silence). If instead of triggering the gate, the knob simply increases/decreases volume or gain, you have a problem on your hands (IC5). Do this with the boost on and off. The one encouraging sign is it’s problematic with the lo jack too, but I don’t know how whether that gets you out of the woods.

Off topic sort of.....Apologize in advance but.....Why would someone want a signature amp anyway? Sames goes for guitars... Yngwie sought out and used what he could...developed his *own* sound making guitar history...wtf would any artist want to rehash what has already been done...I'll never get it..

 

[Karl Brake]

I

Why would someone want a signature amp anyway? Sames goes for guitars... Yngwie sought out and used what he could...developed his *own* sound making guitar history...wtf would any artist want to rehash what has already been done...I'll never get it..

I tend to agree, but I swear by the Satriani JVM. In this case, the sig model just cleared up the problems of the stock JVM410H. I don't want to sound like Joe, but that model makes me sound like myself, without fighting the issues of the stock model. As for Malmsteen, that guy is brilliant, but sketchy. He seems to be really selling himself as a brand. Remember that the Led Paul was sort of a signature model. Some aren't jive, just sayin'.

 

[V-man]

Why would someone want a signature amp anyway? Sames goes for guitars... Yngwie sought out and used what he could...developed his *own* sound making guitar history...wtf would any artist want to rehash what has already been done...I'll never get it..

A distant 4th to “WTF would you want a relic?!” in hijacks and rehashes (I don’t get it either) but here goes.

- Marshall offered features you couldn’t get on their amps, Particularly the 2203KK (which was the meanest out-of-the-box sounding Marshall I had ever had or heard) and the 410JS.

- Some outfits [Gibson] won’t do a proper or interesting spec, finish, whatever outside of 5-figure CS and once in a blue moon a sig comes along delivering much of what you might have wanted for a fraction of the CS price.

- Because some of them are so intrinsically cool that they become popular if not ubiquitous on their merits to the point they are significant to the entire playing population in addition to the artist’s fans. Again, the irony going back to the FOS hypocrisy of anybody “hating sigs“ while having/wanting RRs, KVs and LPs to name a few popular/ubiquitous SIGNATURE guitars.

Not a YJM fan at all but who wouldn’t want the features of thr YJM-100 (if it was actually solid gear)? Same for metalheads and the JS and KK (which looks like shit w that tribal graphic, but it’s about the engine, not the vinyl decal).

 

[6StringMoFo]

I

I tend to agree, but I swear by the Satriani JVM. In this case, the sig model just cleared up the problems of the stock JVM410H. I don't want to sound like Joe, but that model makes me sound like myself, without fighting the issues of the stock model. As for Malmsteen, that guy is brilliant, but sketchy. He seems to be really selling himself as a brand. Remember that the Led Paul was sort of a signature model. Some aren't jive, just sayin'.

K that made me twitch a little.

The Les Paul was a guitar designed in collaboration between an artist and a manufacturer.
Like the EVH Wolfgang.

It's not a strat with different pickups slapped with some artist's name on it.

The YJM on the other hand is a PCB playground stuffed into a vintage head cab.

 

[anitoli]

So the chip in question is an RC4558D? I am just going on what i could find on the web.

 

[Stefan_E]

Off topic sort of.....Apologize in advance but.....Why would someone want a signature amp anyway? Sames goes for guitars... Yngwie sought out and used what he could...developed his *own* sound making guitar history...wtf would any artist want to rehash what has already been done...I'll never get it..

Your Gibson Les Paul is a signature guitar. Does it really matter?

 

[V-man]

The Les Paul was a guitar designed in collaboration between an artist and a manufacturer.
Like the EVH Wolfgang.

Aside from the infamous “Gibson Jimi Hendrix Strat” (they made some years before suing every swinging dick into the stone age for design infringement), how many sigs can you think of that aren’t designed in collaboration with an artist?

I get the subtle palette of hues between getting a Sandoval Replica commissioned to RR’s specs, getting a White LP custom bc you first admired one in his hands and grew to appreciate the guitar, and getting a 7-string reverse HS RR with no reverence for the artist from whom the design was spawned, but it‘s all fruit from the same tree, regardless if one finds it to be apples and oranges.

Because an artist was influential, some want to be the guy, some just want to be able to sound like the guy’s certain record (how many fucking Free/all right now refs do we get here on tone?) and some appreciate specs/features completely apart from any connection with the artist (Grace Potter Flying V being a prime example). That doesn’t get anybody off the hook who seriously questions/judges here and supports it there.

Nobody came out of an egg learning scales and creating whole cloth music. Everybody admired and emulated some. The Sandoval V replica can be seen on the wall of Metallica’s shithole (Cliff ‘em All). Dave Mustaine and Scott Ian both publicly remarked they were getting a 1959RR (the former intending to do some recording with it).

 

[Adrian R]

Your Gibson Les Paul is a signature guitar. Does it really matter?

I guess, never really of it in that manner. But, didn't LP himself create that guitar, a solid body electric, an innovative *model*, and then Gibson started producing them more so as an evolutionary step in electric guitar design? Sorry, perhaps some rhetoric..but no..it's not the same. Marshall amps in various forms were out for about two decades before Yngwie emerged on the scene.