Before I really knew much about amplifiers or even guitars, I was highly suggestible to the imagery that is presented in all of the common guitar literature. The kind of material that costs thousands of dollars in ad campaigns.
I wanted to sound my best like any guitarist naturally would want. I believed the weak link in my sound at the time was my amplifier (instead of my playing which still could use some help). I had been playing through a Dean Markley amplifier and while it got the job done and had served me for years, I was searching for something of an icon!
Around that time, the second series Marshall Valvestate amplifiers were being released. They bear almost no resemblance in sound or design to their namesake. The older Plexi style and non master volume JMP Marshalls are based around a modified Fender Bassman circuit while the master volume JMP and early JCM800 amps are based on a modified Plexi/JMP style amp.
Now having a lot more experience, I find it difficult to get anything I like out of a non master volume Marshall. The controls are somewhat unresponsive and the amp piercingly bright or exceptionally dull depending on the channel and tube set. I've heard others use these amplifiers in ways that I only dreamed of, but much like the Big Muff, I decided that it is best to leave these non master Marshalls in the hands of serious players who demonstrate that tone is in the fingers and not the amp.
After the single channel JCM800 amplifier, I pretty much lose all interest in Marshall amps. The circuitry becomes way too convoluted.
Anyway, the Valvestate amplifiers share zero ancestry with these notorious Marshall amps. In fact the only real connection is that the amplifier says Marshall on it and has similar cosmetics. But I didn't know any better.
I bought the smallest model in the line. The VS15R. There was also a non reverb variant made. The VS15 and VS15R have the distinction of being the only valvestate models NOT to feature a tube of any sort. All of the other models had a 12ax7 in the preamp somewhere. I don't remember those amps sounding particularly good, but hybrid amps were a big deal at the time. Some companies like Music Man had tried solid state preamps with tube driver and output stages. Nearly every other company tried a tube preamp with a solid state output.
The VS15R featured a nominal 15 watt output into an 8" speaker and had a simple set of controls. It actually sounds pretty good for a cheap practice amp. I've heard cheap tube amps which sound much worse as well as more expensive solid state which sounds far worse.
The amplifier is actually pretty simple inside. It features a set of 4558 chips for the preamp, a 1458 on the reverb, and a TDA2030A on the output.
After becoming a bit wiser to amps, my Marshall began to see less and less use as I had gotten into vintage Blackface Fender, Ampeg, and Gibson amps from the 50's and 60's. I eventually gave the amplifier (box, warranty card, and manual!) to my brother who was learning to play guitar.
He tinkered with it and enjoyed it....Until...
His house was burglarized. His guitars and amplifier were amongst the stolen items. This sort of burglary had been going on in his Florida community alongside of neighboring communities. The thieves would break in and take what they wanted and pawn it through a series of friends and acquaintances. They had gotten away with it for some time as nobody ever had serial numbers for stolen items to pin them to the crime.
That is until they stole the Marshall VS15R without taking the box which has the serial number marked on it.
The amplifier turned up in a local pawn shop. Florida has some very unfair rules regarding victims having to buy back their equipment, but I suppose it is in return for their full cooperation. My brother was forced to buy back this amplifier for the original pawned price.
I'm sure he slept a little easier on that injustice knowing that the person who pawned it was sitting in a police station for questioning. Turns out it was a woman who pawned it for her boyfriend who happened to be the one who stole the amplifier. The police were able to take finger prints off of the amplifier and match it to the suspect. The amplifier had finger print dust on it for years almost as a trophy that my brother would show off.
Fast forward a few years, my brother was playing through the amplifier. Took a break. Came back to play some more and the amp no longer worked. It made an awful steady tone which was not sensitive to the volume or tone controls.
I recall in my younger curiosity opening the amplifier. All of the parts laid out looked like Greek to me. Not this time. I had scored some time at the bench while working for Ibanez. I have always been naturally pretty good at troubleshooting things and this was no different than any other amplifier I had worked on...except I didn't have a schematic nor could I find one online.
I probed around and took some voltage readings. I noticed the power rail for the output IC was 21.2 Volts which is just .8 volts shy of the absolute maximum for the TDA2030A chip. I took some readings on the chip and got all kinds of screwball numbers. I removed the chip and researched it a bit.
I learned that the TDA2030 is a popular choice for small amplifiers because it requires very little support circuitry. Countless examples were shown. One thing they all had in common was how sensitive the chip was to exceeding the voltage rating.
I figure a power surge probably did the amp in. And being that this amp was a hero (even though many will never know it!), it was not fitting that it end up in a landfill!
I replaced the TDA2030A with a TDA2050 which has a slightly higher voltage rating and a higher wattage rating but left the rest of the circuitry alone.
Reassembled. Crossed my fingers and turned the amplifier on for the first time in years.
Fired right up! The hero has been resurrected!
And that is the story of how a Marshall amplifier stopped a crime ring...with a lot of tangents and technical information thrown in.
