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#31 (permalink) |
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Senior Member
Join Date: Jan 2009
Location: RICHMOND, VIRGINIA
Posts: 1,510
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Re: JCM 900 6l6 to EL34 Conversion problems
Yeah dude, I would get the 900 fixed, definitely with a Mercury Magnetics transformer. This will fix your problem AND improve the tone. I don't have anything with that brand in them but MM makes a great product.
Just don't listen to Ken. A DSL is more problematic in the long run. It's got way more that can go wrong with it and the tone isn't as good. I'm just going to have to outright say it, I have a DSL and I think they suck compared to other products in the Marshall line. The only people I really hear stand up for the DSL/TSL is if that's all they own by Marshall. Sorry Ken, don't mean to bust your balls but there's a huge chance he can buy a DSL and have something go wrong with it even more expensive to fix. I think the JCM2000 is good for a cheap backup and the weekend warrior. Mine collects dust since I got a real amp. The 900's are going up in price too, a year and a half to two years ago they were selling at a pathetic $400 and now they're going for almost $900 and up. You'll be seeing the price steady at a higher rate since Marshall has reissued the 900. I'd be holding on to it for sure if I had one.
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-I'd rather be a good liver than have one... |
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#32 (permalink) |
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Senior Member
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Re: JCM 900 6l6 to EL34 Conversion problems
An SLX is going to sound different than any other 900 amp, because it is a completely different design, but they kept the 900 moniker. All other 900 models used diodes to provide "clipping." But you knew that already.
Marty
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MARTY ![]() 2009 Gibson Explorer-Hell Raising Machine 1989 Fender Strat Plus USA 2008 Fender Tele USA 2004 Schecter Elite w/DiMarzio's TSL100 with custom 4x12 cab. TSL122 with Man 'O War Speakers. TSL602 #1 with JBL D123 Speakers and 602 #2 with Altec 417 Speakers. "Oh so sweet my friends." DSL401 #1 with Red Fang Speaker and 401 #2 with JBL D123 Speaker. Tubes: Let's just say they are NOS that kick ass. |
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#33 (permalink) |
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Senior Member
Join Date: Jan 2009
Location: RICHMOND, VIRGINIA
Posts: 1,510
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Re: JCM 900 6l6 to EL34 Conversion problems
yeah, I was surprised when I saw they reissued the 4100 High Gain Dual Reverb over the 4100 SL-X. I would have surely thought it would be the SL-X.
Even with the JCM800 RI they did the 2203 with the vertical inputs over the horizontal which is internally designed much better. So thinking they would RI the ones that people wanted more I would have put my money on the SL-X. I'm sure that one sounds great anyway but I have no use for reverb.
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-I'd rather be a good liver than have one... Last edited by American Viking; 07-01-2009 at 11:46 PM. |
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#34 (permalink) |
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Junior Member
Join Date: Jun 2009
Posts: 18
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Re: JCM 900 6l6 to EL34 Conversion problems
Well I've ordered the OT (80 bucks from Weber VST). I'll keep you guys posted. I'm installing it myself so it won't cost anything but the parts. Yes, I'll bleed the caps. No I won't kill myself too much.
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#36 (permalink) |
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Senior Member
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Re: JCM 900 6l6 to EL34 Conversion problems
Wow! That's cheap for an OPT. You got it from Weber? Can you post a link so I can look over their prices? That is, if you got it handy. Otherwise, I can look it up myself. I just want to make sure I get the right page.
Marty
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MARTY ![]() 2009 Gibson Explorer-Hell Raising Machine 1989 Fender Strat Plus USA 2008 Fender Tele USA 2004 Schecter Elite w/DiMarzio's TSL100 with custom 4x12 cab. TSL122 with Man 'O War Speakers. TSL602 #1 with JBL D123 Speakers and 602 #2 with Altec 417 Speakers. "Oh so sweet my friends." DSL401 #1 with Red Fang Speaker and 401 #2 with JBL D123 Speaker. Tubes: Let's just say they are NOS that kick ass. |
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#37 (permalink) |
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Junior Member
Join Date: Jun 2009
Posts: 18
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Re: JCM 900 6l6 to EL34 Conversion problems
Weber Speakers - Making the world a bit louder each day.
The OT will be in next Wednesday. I'll post as soon as I get it installed. |
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#38 (permalink) |
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Senior Member
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Re: JCM 900 6l6 to EL34 Conversion problems
Thanks, I reviewed the information. Did you get the "ballsy" model, or the one with cleaner headroom? I'm familiar with Weber speakers. I didn't know they expanded into amp parts. It's good to know.
Marty
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MARTY ![]() 2009 Gibson Explorer-Hell Raising Machine 1989 Fender Strat Plus USA 2008 Fender Tele USA 2004 Schecter Elite w/DiMarzio's TSL100 with custom 4x12 cab. TSL122 with Man 'O War Speakers. TSL602 #1 with JBL D123 Speakers and 602 #2 with Altec 417 Speakers. "Oh so sweet my friends." DSL401 #1 with Red Fang Speaker and 401 #2 with JBL D123 Speaker. Tubes: Let's just say they are NOS that kick ass. |
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#39 (permalink) |
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Junior Member
Join Date: Jun 2009
Posts: 18
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Re: JCM 900 6l6 to EL34 Conversion problems
Ballsy of course. I couldn't figure out why someone would want to try to get clean headroom out of a Marshall. Kinda defeats the purpose. Plus, at 100 watts, I've got way more headroom than I need anyway.
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#40 (permalink) |
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Junior Member
Join Date: Jun 2009
Posts: 18
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Re: JCM 900 6l6 to EL34 Conversion problems
So I just got the new Output Transformer in today. I installed it and re-biased again. Plays just fine but still gets freaking hot. So hot I can't turn the knobs after about 30 minutes of playing. Somebody please help me. I can't figure out what's going on!!!!!!!!!!!!!!!!!
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#41 (permalink) |
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Member
Join Date: May 2009
Posts: 41
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Re: JCM 900 6l6 to EL34 Conversion problems
better hope your power transformer has enough heater current to run el34s
4 -6L6 need .9 amp each tube thats 3.6 amp on 4-6L6 4-El34 need 1.5 amps each tube thats 6 amps on 4- el34s thats almost double the amount of current the power transformer may not be overrated by that much Last edited by pleximajor; 07-10-2009 at 09:51 AM. |
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#42 (permalink) |
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Junior Member
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Re: JCM 900 6l6 to EL34 Conversion problems
Hello,
in my JCM 900 MK3 from 1991 there is missing the the extra grid fusees inside. I do not mentioned what them for - and placed 6550 Tube´s to run my amp. Quite funny and strong sound. Yust some of the United States in my room. ... Until a year later one of the tube´s kicked of. It burned my whole amp,cause the mostlys in there is for maximal 500volts. The Grid of an 6550 Tube´s got upon to 670volts. The Grid of an 5881 Tube´s got upon to 470volts. In fact of loosing one, there is a lot damage to be done by 670volts trespasing up to mainfuse. Today,after repair,i use 5881 better.Sounds also good enough for angry cats. |
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#43 (permalink) |
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Senior Member
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Re: JCM 900 6l6 to EL34 Conversion problems
Geeze, how'd you manage to get 6550's running for a whole year? 670volts should've killed it in no time.
Btw, which country in Northern Europe you from?
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Marshall JCM900 4100 (6L6) (1995) ![]() Marshall Valvestate 1965A cab (????) ![]() Cort VX-2V (2008) ![]() TUBES/SPEAKERS Power: Groove Tube 6L6GCB Phase Inverter: Sovtek 7025 Pre: V1 - N.O.S Mullard ECC83. V2 National 12AX7A Speakers: Celestion G10L-35 Marshall forever ![]() My tube amp & Real Music appreciation forum |
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#48 (permalink) |
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Senior Member
Join Date: Jan 2009
Location: RICHMOND, VIRGINIA
Posts: 1,510
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Re: JCM 900 6l6 to EL34 Conversion problems
it's time to take this thing to a qualified tech. i wouldn't bring it back to the same guy that told you about the OT.
if the chassis is getting hot, you need to play this amp with everything exposed so you can locate the source of the heat. the chassis shouldn't get hot at all and it leads me to believe that maybe something drawing current is either arcing or touching part of the chassis. it's hard to say without being able to experience this up close but if we're running low on ideas. on the positive side, atleast you have up to date caps and a new transformer.
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-I'd rather be a good liver than have one... |
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#51 (permalink) |
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Senior Member
Join Date: Apr 2009
Location: Melbourne - Australia
Posts: 144
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Re: JCM 900 6l6 to EL34 Conversion problems
Harp,
I know this is a bit late but I just had my 900 4100dr retubed 2 weeks ago and when I dropped it off I enquired about the EL34 mod, mine is a 6l6/5881 model. The tech said he has worked on both type amps and did not recommend doing it. He works for Marshall and said that he cannot really hear any difference in these amps with the two tube types. Now I have not heard an EL34 model but took his word for what it was worth. Needless to say after the retube I find that mine has far more bottom end to the point where I run the bass at 5.5 now, used to be between 8 and ten. With the chB Vol at 5-6 and gain at about 14 it sounds pretty much identical to my mates 800 at near full gain and with a Les Paul going through it I cannot be happier. If the fatter sound is what your after then I suggest reversing the mods done and put 6L6WGC's in like I did. As others have said the tones are there, it's just a matter of spending alot of time tweaking the EQ to find the right sound. Have a look at the Duncan Amps tone stack calc and it will give you a good idea of how the interaction of the eq works. I always thought high bass, middle on the mids and high treble, but the eq when I had a look at the tone stack gizmo I really understood how to get the best sound out of the amp. Rob
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JCM900 4100 DR + 1960 A + B + Powerbrake Ibanez PS10CL Paul Stanley Custom Gibson LP Traditional Epiphone LP Custom No pedals......... |
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#52 (permalink) | |
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Senior Member
Join Date: Jan 2009
Location: RICHMOND, VIRGINIA
Posts: 1,510
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Re: JCM 900 6l6 to EL34 Conversion problems
Quote:
Does this guy really work for Marshall? If there's no audible difference between tube types then we're all wasting money and should just go to solid state.
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#53 (permalink) | |
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Senior Member
Join Date: Feb 2009
Location: Arlington Heights, IL
Posts: 607
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Re: JCM 900 6l6 to EL34 Conversion problems
Quote:
Seriously, I know you're really frustrated and I'm sorry about that! I know you want that amp working. ken |
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#56 (permalink) | |
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Senior Member
Join Date: Apr 2009
Location: Melbourne - Australia
Posts: 144
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Re: JCM 900 6l6 to EL34 Conversion problems
Quote:
As I said I have not heard an el34 4100 and was only passing on what he told me. Bottom line is if you want an EL34 amp get an EL34 amp I'm very happy with mine. However it really comes down to the guitars used, eq and guitar tone controls. Lots of mucking around but all the more fun
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JCM900 4100 DR + 1960 A + B + Powerbrake Ibanez PS10CL Paul Stanley Custom Gibson LP Traditional Epiphone LP Custom No pedals......... |
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#57 (permalink) |
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Junior Member
Join Date: Jun 2009
Posts: 18
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Re: JCM 900 6l6 to EL34 Conversion problems
Just thought I would update everyone. After taking the amp to the amp tech I found out that the "matched" quad of tubes that I got from JJ was not so matched. Because I was only checking the bias on one of the tubes, I had it biased way to hot. The amp tech switched the tubes around so that both sides were more or less balanced, then re-biased. The thing still runs pretty hot, but it's not near as bad as it was. Thanks for all the helpful advice.
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#58 (permalink) |
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Junior Member
Join Date: Sep 2009
Posts: 3
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Re: JCM 900 6l6 to EL34 Conversion problems
Hi,
owner of an old JCM900 50W combo; this is the EL34 version and a.t. Bob at Eurotubes it plays on 6L6, KT77 and also JJ's 6V6. Tried them all, no problems. Just measure the PLate Voltage beforehand to find a suitable tube. The 6V6's are great, starts cranking before the roof takes off. Of course a Weber Silver Bell Alnico 75W helps .. instead of the G12T-75 Celestion which is horrible in this amp. |
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#59 (permalink) | |
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Senior Member
Join Date: Jan 2009
Location: RICHMOND, VIRGINIA
Posts: 1,510
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Re: JCM 900 6l6 to EL34 Conversion problems
Quote:
Bob is the man.
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-I'd rather be a good liver than have one... |
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#60 (permalink) |
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Senior Member
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Re: JCM 900 6l6 to EL34 Conversion problems
Wow, 6V6's in a 6L6/EL34 type amp, sounds interesting, maybe I'll have to try it after I've had my amp completely fixed.
And harp, maybe that could've been my problem, I had a quad of JJ KT77's and my amp got really hot (And the bias wouldn't stay put). They ended up red plating, and I took it to the tech with the suspicion something was broken, he said it was fine and it just needed some 6L6's (Apparently he also had to look up the info on the internet to find out of KT77's would work)... I need a better tech, he also checked over my amp (With the obvious noise problem) and said there's nothing wrong with it. Didn't charge me at least.
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GEAR LIST
Marshall JCM900 4100 (6L6) (1995) ![]() Marshall Valvestate 1965A cab (????) ![]() Cort VX-2V (2008) ![]() TUBES/SPEAKERS Power: Groove Tube 6L6GCB Phase Inverter: Sovtek 7025 Pre: V1 - N.O.S Mullard ECC83. V2 National 12AX7A Speakers: Celestion G10L-35 Marshall forever ![]() My tube amp & Real Music appreciation forum |
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