I was just wondering if and when I need to changes the tubes in my 2525 mini silver jubilee head can i just put the same type tubes in it or does it need to be biased?

I have a 70's JCM 50 W lead I want to replace the tubes - 2 x 6550 and 3 x 12 ax7 ecc83, original GE tubes are in the amp. I am told I need to repalce the power tubes due to the 3 amp fuse keeps blowing. 

how do I notice my preamp valves need to be changed?

thanks you! :)

Hello...I have a JCM 800 2203 that I purchased back in 1981 and I wanted to replace all the tubes in the head after all these years. My amp has many hundreds of hours on it between practice and hundreds of gigs back all through the 80's.  I assumed that I had the standard compliment of Four EL84's in the output stage of the head...Everything I've read stated as such, and all the You Tube Bias Procedures led me down the same path....SO I ordered a matched set of TAD 12AX7's (3),  and four EL34's. Well, much to my suprise, when I took the back metel cover off the head, I did not find four EL34's...What was installed for power tubes back in 1981 was 2- 6550's, and 2- 6L6's. Both larger than the EL84's. Can anyone tell me why they (Marshall corp.) would do this...is there any special reason? I DO NOT want to change ANYTHING about the tonal characteristics of this amp. I would sure like a little enlightenment on the what's and the why's. I am truly facinated at discovering this..Thaks to all...Randy

Hi, I have bought a used Marshall amp JCM2000 TSL100 but the tubes must be replaced so my question is what kind of EL34's should I buy I mean what are the original tubes that are in the amp when he goes out of factory?

Thanks anyway!

I have a problem with my jvm205h. I can hear a rattle while I am playing. It seems to come from the tubes could anyone tell me what I could do to fix this or is that normal? 

Hey, I recently bought this amp (5 months ago) and it was working very well until a couple of days ago. Yesterday I turned on the amp and it's volume was very low on both channels. I had to put it all on maximum in the classic gain channel (Volume and Gain) to get a decent volume for practicing on my bedroom. I reseated all valves, but the problem continues. I also tested the valves hitting them with a pen, but there was no sound that could indicate a bad valve. What should I do?

Hi,

I bought a Marshall YJM100 this July and it's great. As far as Im concerned I'm the 3d owner of this amp so It's obviously not new. Anyway I'm concerned about the normal sensetivity input for the high treble channel. It's basicly no treble, or tone for that matter and it's kind of a bummer cause I can't get that Plexi tone I was after. I'm using my Boss ME-70 to boost the singal and then it sounds okay but I shouldn't have to do that.. 

So my question is.. Is my amp broken or will this be fixed by changing valves? The owner before me didn't change valves and I don't know if the owner before that did eather. (This is a problem that must have occurred from the previous owner since I bought it like this)

Thanks

Having to renew two 6v6 valves in my DSL 15 C, opinions on Groove Tube GT 6v6 please.

I am in a quandry. I have a 1987 50W (2 power tubes) reissue.  Every search I do for this comes up "1987x", and they all seem to have an F/X loop-- mine does not. The S/N is RI935245707. The front is labeled "MK II" and has 2 ch, 4 inputs and looks just like the classic Marshall we all have come to know & love..

1) Does the 'x" mean F/X loop?

2) I know that it is a re-issue and was manufactured in 1993. Is this a "plexi" reissue or a "metal face"? I am not sure if a "plexi" reissue would have an actual plexi faceplate, just the internals.

3) Since I cannot find any info on it, is this some kind of rare bird or not?

4) Can you tell me how many of this model were manufactured or do you have any idea of the value? It seems odd that I cannot find any similar w/o an F/X loop.

Any info would be greatly appreciated.

Hi,

I need to replace the power tubes in my 6100LM 100W Head.

I am looking at purchasing a matched quartet of Tung-Sol 5881 (Medium) from Musician's Friend

Just wanted to check to make sure that these are able to be used in my amp.

I have provided the link to the Musician's Friend Web Site for your review.

http://www.musiciansfriend.com/accessories/tung-sol-5881-matched-power-tubes/210098000118186

Thanks,

Craig

Hy i would like to know if a could use this pedal on my Marshal JCM 900 4100?

This is a valve pedal!

I use yestarday, between guitar and imput, so the  fuse valve melt.

Could you clarify this for mee?

I change the fuse and the head is perfect

Thank you

I about the above in 1985. I just want to confirm what tubes are necessary.

Also, if I could register, that'd be great!

Can I change EL34 (8-pin) to EL34 (7-pin) Vacuum Tubes on my Marshall DSL 100H?

Hi! I have a 2013 jcm800 2203x head. Can you tell what what preamp and power amp tubes were installed at the factory? Thank you!

Hi there. I recently acquired a JCM 2000 TSL 100, put new valves in it but the amp still makes strange loud static noises after starting up for a few seconds and then settles down. On the Marshall forums I was advised to check the motherboard and found it to have the number JCM2-60-00 which apparently is faulty. Can I obtain a motherboard that isn't faulty or would it make more sense for Marshall to service it? Ideas of prices would be great - thanks, Malcolm

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,

Graham

Since purchase amp always had a hum unless I touched strings.  Last month the amp spiked when I turned Standby ON.  Since then lost power on Classic channel and selector switch on head would not change channel, but footpedal works.  I returned to Sweetwater for repair/replacement immediately.  I received back stating "Reverb PCBA pins were lifted halfway off Main, glued in place.  Bias the output tubes...".  At this time I purchased Gibson cables CAB12-BL thinking the hum from bad Sweetwater cables supplied.  Still have hum at 1/4 volume, min Gain setting and the Channel Select on head still does not work.  It used to, and hum acceptable at low volume.  Is this correct, can I get replacement?

Hiya! Can anyone enlighten me about tone pots in Marshall valvestate 2000 avt20 combo. need to change middle desperately, and maybe others. cheers!

Hi, I bought a Marshall DSL40C amp in July from Gearnuts (www.gearnuts.com).  The amp has been working great until yesterday - a crackling buzz began and then I heard a pop and saw a small flash of light.  It looks like the tubes are blown out.  How do I get these replaced under the warranty?

Thank you,

Sean