#1
Okay, so I have a love/hate relationship with my JCM2000. On one hand, it's a Marshall, so that's an instant positive. On the other, it's quite harsh sounding and not my sort of thing at all.
Thing is, I don't know if it's because I'm playing at low volumes (2 at max) or I need new valves or there's something wrong, or if that's just the way they're meant to sound, but it just sounds a bit fizzy for me.
My Blackstar HT20 however sounds great. Really full and smooth, but with plenty of definition.

Other probably important info:
Playing through a V30 loaded 2X12,
Has Svetlana valves all round,
If it was re-valved just before I bought it (like the previous owner said), the valves should be fairly new (march/april) with very little use.

Anyone got any pointers?
#2
Svetlana can mean a couple of things. Are they SED (which were actually made in the old Svetlana plant) or are they actually labelled Svetlana (made by New Sensor who bought the rights to the name)? If the latter, then yeah, it could easily be the tubes, they're rubbish.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#3
I would imagine that they're "new new" rather than "new old" then. Are there any that you would suggest that wouldn't break the bank? I've heard good things about PM Tubes before.
#4
DSL's love JJ's. If it's a head, stick a JJ ECC803 in V1 and JJ ECC83S everywhere else. Only do the power tubes if that doesn't fix it. New Sensor's Svetlana power tubes aren't as bad as their preamp tubes.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#5
This is probably the worst thing that can possibly be done, but can I use the 2 pre tubes currently in my Blackstar just to test if that's the problem and what positions would they go in?
#6
Yes, but if may not tell you a lot. V1 is the main one but you can try them in various spots and see what happens. You won't hurt anything trying.
Buy a couple of JJ's to try it with, they're not expensive and you should have spares anyway.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#7
Thanks for the advice!.
One more question:
I can get JJs from Karltone with three options; factory tested (£7.95), premium tested (£9.25) or balanced triodes (£10.50).
Is there any specific reason to go for balanced triodes over just premium tested?
#8
No. Balanced tubes are supposed to be for the phase inverter but no phase inverter is truly balanced anyway so it really doesn't matter. It's pretty much snake oil.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#9
Right, so save the £1.25 and just get premium tested?


1 & 2. Premium Tested & Balanced Triodes are tested on specialised digital and analogue testing equipment by Karltone as follows

Gain (A)
Transconductance (gm)
Noise (dbv)
Microphonics
Emission Quality
Grid Leakage
Shorts

Test results are provided with purchase


Thanks for all your help!
Last edited by CorrosionMedia at Sep 16, 2014,
#10
Yeah. Premium tested is probably bs anyway. I just buy whatever is cheapest.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#11
Well that's confusing... I'm not sure which order they're in (V1, V2, etc.) but the furthest left is a JJ ECC83S, the next a Svetlana ECC83, then another, then another JJ ECC83S. The two power valves are Svetlana EL34s.

Should I still replace them? After all, V1 is a JJ and it looks to be in fairly good condition.
#12
I have a DSL100 and I run a new Mullard 12ax7 in V1 (closest to the input jack), JJ ecc83 in V2/V3 and a Sovtek 12ax7LPS in the PI with SED EL34 in the power section (the real Svetlana tubes). While I have used other combos with better results, those tubes are pretty expensive so I kinda save them for a rainy day

Best results I have used are NOS Mullard ecc83 V1, RCA 12ax7 V2, Telefunken ecc83 V3 and a JAN GE 5751 in the PI with SED EL4, but your looking at a $600+ retube cost
2002 PRS CE22
2013 G&L ASAT Deluxe
2009 Epiphone G-400 (SH-4)
Marshall JCM2000 DSL100
Krank 1980 Jr 20watt
Krank Rev 4x12 (eminence V12)
GFS Greenie/Digitech Bad Monkey
Morley Bad Horsie 2
MXR Smart Gate
#13
I doubt its the tubes. You probably just dont like the amp. Try lowering the presence if the amp has a presence knob. Maybe reset all the controls to 5 and work from there. What settings are you currently using?
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#14
Well normally, I use the classic gain channel with these settings:
Gain - 8, Bass - 4, Middle - 5, Treble - 7, Presence - 5, Deep - out, Tone shift - out.
I've tried setting the treble and presence to 0 and 10, but there's still a very buzzy tone to it.
I've previously tried using it as a standalone power amp by running my Line 6 PODstudio UX1 into the FX return and there was still some buzzing present.
Here's an example of roughly how it sounds (modelling with my UX1

The first chords and riff are with the effect turned on. It sounds just like that.
The second ones are with the effect turned off - how it should sound.
https://soundcloud.com/corrosionmedia/amps
(Dat sloppy skindred tho)
#15
Quote by CorrosionMedia
Well normally, I use the classic gain channel with these settings:
Gain - 8, Bass - 4, Middle - 5, Treble - 7, Presence - 5, Deep - out, Tone shift - out.
I've tried setting the treble and presence to 0 and 10, but there's still a very buzzy tone to it.
I've previously tried using it as a standalone power amp by running my Line 6 PODstudio UX1 into the FX return and there was still some buzzing present.
Here's an example of roughly how it sounds (modelling with my UX1

The first chords and riff are with the effect turned on. It sounds just like that.
The second ones are with the effect turned off - how it should sound.
https://soundcloud.com/corrosionmedia/amps
(Dat sloppy skindred tho)


Sorry, are you using the UX1 only? How are you recording the DSL? Reading/listening, I'd say too much gain.
#16
That's just a simulation using the UX1 to demonstrate what it [the amp] sounds like. If I bypass the preamp on the JCM by plugging straight into the FX return, the buzzy distortion is still present
Last edited by CorrosionMedia at Sep 16, 2014,
#17
Quote by CorrosionMedia
That's just a simulation using the UX1 to demonstrate what it [the amp] sounds like. If I bypass the preamp on the JCM by plugging straight into the FX return, the buzzy distortion is still present


Okay, i get ya. I can only listen on my cell phone speaker so i couldnt really detect the buzziness. Just out of curiousity, is your cab closed back?
Quote by suckmahnuts
Watterboy, I love you.

Quote by davrossss
You are now my favourite person on UG.....You write cool shit.

Quote by wannabestoner69


#19
I guess your best bet is to try swapping in tubes from your blackstar and see if it makes a difference (as stated above). Look up the owner manuals for both amps and find the diagrams that show the different tube positions.

The only reason I said that I doubt its the tubes is because I have owned amps that had issues with fizz or being too dark, ect. and ive tried swapping tubes in and out, but it hardly ever made a noticeable difference. It didnt solve my problems at least.

One other thing that couldnt hurt to try is swapping out your speaker cable for another speaker cable. I doubt thats your issue, but you never know.
Quote by suckmahnuts
Watterboy, I love you.

Quote by davrossss
You are now my favourite person on UG.....You write cool shit.

Quote by wannabestoner69


#20
I was thinking about putting the EL34s from the JCM into the Blackstar so that I know it's definitely them. Do you know if I'll have to re-bias for this quick test? The Blackstar recently went back for a full service with all new valves and a bias, so will I have to reset the bias for this test with the marshall's valves?
#21
Yeah, it will need to be rebiased. You can swap the preamp tubes around without adjusting anything but power tubes should be rebiased or at least checked.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#22
^he is correct.
Quote by suckmahnuts
Watterboy, I love you.

Quote by davrossss
You are now my favourite person on UG.....You write cool shit.

Quote by wannabestoner69


#23
I think this is as far as I can go then.
I'll have to pass it over to my Dad who did a valve theory course in college and has had many jobs in electrical engineering, so he'll probably be better qualified than me to poke around with mains voltage. The only down side is that I'll have to wait until he's got some spare time.
Hmm... I wonder if I can bribe him with cash...

Thanks for all your help anyway guys!
#24
get a 12AT7 and try it in a few different spots. they can help a bit. maybe enough.

a full set of JJ's are worth it. they DO change the tone a bit or alot (just matters what you had in there).

worst case scenario they don't do much better and you have quality backups for the DSL or for another amp.
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