JCM 2000 TSL 122 - volume loss


I have had my amp JCM 2000 TSL 122 combo for a few years. I used it occasionally when I first acquired it (around 2008) and then fairly regularly in a band for about a year in 2009/20010. It was then put in my wardrobe and came out to use ocaasionally for a couple of gigs and then went back in the wardrobe until earlier this year.

In 2016 I have gotten together with some friends to form a new covers band and we have rehearsed at pretty big rehearsal room volume with live drums etc. at an average of 2 rehearsals a month since March.

Today, I started to set my amp up as usual - plugged in and turned on with standby. Took off stanby with all 3 channel gains and volumes at ZERO. 1st channel (Clean) some gain + some volume (uaual position around 2 and a bit....rarely get it to 3, haha!) and it made all the usual signs of working well and giving me a great clean sound.

Turned to the other guitarist for a quick conversation about pics he bought on e-bay and I found my volume dropped!!??!!

I checked leads, connections, another guitar, but my Marshall is not doing what it has been doing. Our other guitarist put his guitar through it and it needed almost full gain and full volume on each channel to get any volume on the output.

I turned ot off and used an amp that the rehearsal studio had available. Effects and leads all good, so the issue is definitely the amp.

Am I experiencing a dead valve, or set of valves, or could it be something more sinister? This is my first valve amp and appreciate that these things are much more sucsceptible to issues and need much more maintenance than their solid state counterparts.

Any advice on this would be much appreciated. I have searched the issue and found that there are some sites with negative thoughts towards the JCM 200 series and the TSL 122 in particular with biasing issues etc., but what I am reading is going over my head a little, but looks quite damning???

Thanks for any help,


asked 01 Oct 2016 at 07:51 PM

Graham Judd
Answers: 1


Hello Graham,

We would recommend that you have your TSL122 looked at by a qualified engineer, it could be due to a faulty valve but without seeing the amplifier it is hard to diagnose. If you are based in the UK we would be happy to look at your amplifier for you and we give a free quote before we go ahead with any repairs. To make any arrangements please e-mail jgreen@marshallamps.com, if you are outside of the UK please let me know where you are based and i can give you details of your nearest distrubutor. 

answered 03 Oct 2016 at 08:16 AM

Hi. Except few other issues i have exactly the same problem with volume loss and sure it is not valve fault since just recently i have replaced all valves to mullard in power amp and jj in preamp. The main and biggest problem that i live in Tajikistan and here no any Marshall distributor or service centre! We have qualified engineers but not experienced in modern valve amps. By modern i mean everything produced after 1985:) Interesting that i had my TSL122 looked by one local engineer and i was surprised.. after we switched it on my Marshall was operating as usual and no volume loss:)) engineer guessed that there might be some bad connections/contact and due to vibrations during transportation to engineer it repaired by it self:) after three months again the same situation with volume loss. I never used my TSL122 on clean gain and volume on 12 o'clock with VPR off! Now this is my usual minimum settings during practices with my band. However i have good friend and he is good engineer but in any case needs guidance where to start and how to proceed. Is it possible to get online consultations and guidances? I really rely on this Marshall support platform and this is my only hope to bring back sweet British sound of rock!
Except of problem with volume loss i have issues tone suck and volume loss on fx loop mode and i don't know is normal or not but after one hour of playing the panel is very hot even it is not possible to keep hand on it.
Many thanks for any kind of support!

Best regards,
- Firdavs Sheraliev 16 Apr 2017 at 08:21 PM
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