3203 Marshall reverb

[hippietim]

this reverb sounds pretty lame really. could be that something is wrong with it because it's noisy. the amp is very quiet until i kick in the reverb. Any ideas? new tube perhaps?

[thebisch]

Re: 3203 Marshall reverb

I used to have a Marshall 5210 (JCM 800 era solid state channel switching combo) which did the same thing you are talking about. Eventually the reverb died altogether. It turned out that the opamp in the reverb driver/return curcuit died. I replaced the opamp and the amp worked like new. Seeing as the 3203 is of the same era and has a solid state pre and reverb driver, the cuicits are probably very similar or the same as my 5210. Something to look into at least. Also look into the switching components. IIRC some Marshalls of this era have problems in that area as well.

[Cleveland Metal]

Re: 3203 Marshall reverb

My friend owns this amp and is an electronic engineer.

Could you please explain exactly what you mean? More detail.

The amp sounds lame or the reverb sounds lame?

The amp is noisy? When is it noisy? What kind of noise? hum? static?

Is it a volume jump or is it getting noisy when you kick in the reverb? What exactly is it doing?

[hippietim]

Re: 3203 Marshall reverb

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My friend owns this amp and is an electronic engineer.

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Tell him thanks!

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Could you please explain exactly what you mean? More detail.

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I am beaming my thoughts to you right now. [img]/images/graemlins/smile.gif[/img]

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The amp sounds lame or the reverb sounds lame?

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The reverb sounds kinda lame.

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The amp is noisy?

[/ QUOTE ]
Not with the reverb off.

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When is it noisy?

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When the reverb is on. The higher the reverb level, the noisier it is.

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What kind of noise?

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Hum.

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Is it a volume jump or is it getting noisy when you kick in the reverb?

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Just gets noisy when I kick in the reverb.

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What exactly is it doing?

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Hmmmm...

Thanks!

[Cleveland Metal]

Re: 3203 Marshall reverb

Tim... He says it's broke...

[Twisteramps]

Re: 3203 Marshall reverb

I wonder if it could be a problem w/the reverb pan itself?

Pete

[Cleveland Metal]

Re: 3203 Marshall reverb

Ok, Seriously now... hehe...

Check the connection where the reverb send/return wires plug into the reverb pan, make sure they're clean and not corroded. Also, run those wires away from the metal amps chassis, and transformers as they can pickup stray electric and magnetic fields. if possible, run them along the top of the wooden box and secure them.

He has seen that many of marshall heads with reverb pans are susceptible to this.

If you try these things and to no success, we'll talk more.

[hippietim]

Re: 3203 Marshall reverb

[ QUOTE ]
Ok, Seriously now... hehe...

Check the connection where the reverb send/return wires plug into the reverb pan, make sure they're clean and not corroded. Also, run those wires away from the metal amps chassis, and transformers as they can pickup stray electric and magnetic fields. if possible, run them along the top of the wooden box and secure them.

He has seen that many of marshall heads with reverb pans are susceptible to this.

[/ QUOTE ]

Cool! I will check this stuff out.

[ QUOTE ]
If you try these things and to no success, we'll talk more.

[/ QUOTE ]

Or Tim won't use the reverb [img]/images/graemlins/laugh.gif[/img] [img]/images/graemlins/laugh.gif[/img] [img]/images/graemlins/laugh.gif[/img]

[hippietim]

Re: 3203 Marshall reverb

so it must have been a bad cord or something - i haven't had the problem anytime since.

[charvelguy]

Re: 3203 Marshall reverb

that has a pretty decent reverb pan in it..you should be diggin that stack... the price ya got it for was a steal.

[hippietim]

Re: 3203 Marshall reverb

it's very good for sure. but i honestly don't see myself hanging on to it for much longer. i'll probably keep the cab though.

[charvelguy]

Re: 3203 Marshall reverb

Yeah, it does a decent JCM800 sound, but the one knob deal is pretty limited. Nice amp for mods tho.

[hippietim]

Re: 3203 Marshall reverb

I read about some mods on Harmony Central but I didn't see any links to schematics or other specs. Do you have any links?

[charvelguy]

Re: 3203 Marshall reverb

I don't have any links handy on this computer. (different system from when I worked on the amp) I believe there's some definitive instructions in the postings themselves. One for the clean mod. I think another one was cutting the negative feedback loop and doing something with it (sorry do not recall) for more gain. There may be some in a google search too.

[Rupe]

Re: 3203 Marshall reverb

Just clip one leg off of C13 on the circuit board...you can't miss it when you open the chassis. I did this to mine and it really opened the amp up. It amkes the biggest difference with the clean channel but it wakes up the drive channel as well.