Marshall 5210

I recently bought this solid state Marshall from late 80’s. Someone had modded it a bit, and it was in worn condition. The switch has been changed, and headphone out was modded to be speaker out. Tolex was ripped from here and there, and the front grill had lost its original colour. Couple of other issues also revealed in closer inspection.

Specifications are as following:

• 50-watt 2-channel solid state
• 12″ Celestion G12M-70 4Ω speaker
• Spring reverb
• Effects loop

Actually 5210 is a solid state version of  the 4210 (JCM-800) combo. Although I am a pure tube amp enthusiast, I somehow digged this one. I bought this for 100 euros, and with this money I got quite nice looks, very sturdy cabinet, nice sounding spring reverb and enough but not too much power for home training. Some features still really sucked, so it was time to dissassemble the whole thing into pieces.

The very first thing to do was to change the speaker. The stock Celestion G12M-70 sounded very harsh, so it had to go. As there was a lack of lower end with the stock speaker, I swapped it to Eminence Texas Heat, which is my absolute favourite within all the speakers in the market. Had two Fender Blues Juniors earlier with this speaker, and it always sounded perfect to my ears. Also, it’s known to have warm and fat tone, so it should be a perfect fit with this amp. I also changed the speaker cable to Spectraflex’s cable, and cut it to suitable length:

Next thing to do was to fix the horrible shotgun-like loud pop when shutting off the amp. It’s hardly loud enough to do any harm to  speaker, but it can be really annoying to be shot every time after playing. Turning down the volume didn’t help a thing, so something had to be done.  In this case, the actual reason for this loud pop seemed to be the DC-power bleeding to the signal path, and due to a sudden voltage change during shutdown the shotgun was fired. In that case it would most probably originate to some power supply’s leaking capacitor. Instead of tracking down the one or changing them all I decided to fix it with the rc snubber, which provides an alternate path for this current to flow during shutdown. Basically, it’s nothing but a 100 ohms resistor and 1uf cap in series between the the two posts in the power switch before the power transformer:

As the cap has to be rated at least 250V or something it’s quite big, but there was well enough space for this assembly. The resistor is hiding below the cap in the picture. As a result the whole explosion is gone. It’s dead quiet during the shutdown now. I also changed the power switch to be more like the original one, because the green rocker switch was ugly to my eyes. I also rerouted some cables under the hood to diminish the disturbances.

The next thing to do was to renovate the front grill. It’s been black earlier, but during the years it had turned to dirty brown. The difference is well visible after removing the Marshall-logo:

Bought some black’n silver grillcloth for 6 euros from the local dealer, and fitted it carefully over the original front panel. After putting the original logo into place it looks very nice to me. After cleaning the tolex with vinyl renovating liquid and glueing all the tears the amp looks like a new. The new switch is also visible in the picture. Too bad my camera somehow warps the pattern in grillcloth.

With some 60 euros I gave this amp a new life. Being a solid state amp it sounds very good after the speaker swap.