The Vesperado Mod thread for the JCM2000 TSL-100: VERSIO DJENTER

[mickeydg5]

Where's the sound bits?

 

[Vesperado]

Soon my friend, soon...

 

[Vesperado]

Phase III is good to go.

V1A 231 241
V1B 238 250
V2A 246 258
V2B 235 245
V3A 416 432
V3B 239 247
V4A 266 275
V4B 286 295
V5 507 529
V6 not used
V7 not used
V8 507 529
V3pin3 253 261
DC rail 23.6 sty, 23.2 load see notes below

125 / 130 VAC, respectively.

Notes: I initially tried a 110R 3W for Rear R21, which knocked the rail down a volt, but when I ventured to give 'er 130 VAC, the fuses blew. So I reverted to 100R and linked the fuses KNOWING it faired well in those conditions previously. Until I replace them, I am not taking the risk to merely get a reading for 130 VAC. The amp is plenty loud at "1", again. The measurement given is with the 100R stock value.

For those planning to venture into HIGHER VOLTAGE territory, the amp needs a proper minute, 60 seconds, at minimum, to stabilize. Additionally, I am currently not planning to run the amp with the new values higher than 130V. So those who do will be completely on their own.

Main R61/62 may be made 3k9/2k for those who never plan on exceeding 125 VAC. The goal is to keep the voltage across V3A anode well under 450V to satisfy the servicability of both the filter caps at the end of the rail and the tube itself. V1/2 loads are likewise effected when adjusting R61/62, so keep that in mind.

The only other way I can think of in knocking down the volume of the amp, aside from the VPR, is a PT with a lower B+. Truth be told, it has an extra valve in the preamp, so "cranking" it undertakes a whole new definition. Make sure you are standing 50 feet away or so if you do, unless you're deaf or something, or want to be.

The 125 VAC is the way to go, nonetheless, for the lows are refined and clear, and the high mid harshness, or honk, dissipates. The Tone-Shift/4u7/5n1/2M2/500k/PII.2150p/PIII.2n5 configuration will knock your socks off, pummle your chest, rob it of its air, and roar with authority like none other. It's just short of actually breathing fire. Everybody can thank me later...

(Superceded.)

 

[Vesperado]

I retallied the figures for tonal combinations for the amp, though not including the Deeps, VPR, or SPL bleed. Following the Phase III rewire they are:

16 for Green
240 for Amber
240 for Red

However, not all combinations serve all axes/pedals/etc. Some are more useable than others, depending upon the user's setup, ofcourse. Main C12 set at 4u7 with V2 Grid Leaks at 2M2/500k are unuseable for the Green channel. This means the user would do better to find a suitable clean amp to switch in during the course of a song/set list should they elect to employ the 4u7-2M2/500k for the drives; unfortunately there is no work-around outside of implementing a relay, for TR2 cannot offer its support, atleast not for my mod. Nonetheless, for those who can dispense altogether with the big bottom crunch need not even so much fret a sweat.

Also, since acquainting myself with the new setup, there are some audible improvements. With the B+ rail balanced, V1 now amplifies nearly abreast with V2, and V3 lowers to meet V1/2. This smoothens out the Normal modes in removing the associated "honk" or "bark" of the mid freqq. A happy coincidence. It would be interesting to view all the improvements through an oscillascope, nevertheless, the audible tone has most certainly improved having implemented the changes.

 

[Vesperado]

Considering those who might not wish to incorporate Americanized big bottom tones, and who rather would favor in keeping their amp more or less "British", I am including an "alternate mod" which is simpler, and, requires less labor and parts. It will be up to the owner whether or not the Clean channel should remain stock, in which case, they may disregard the change at Main C24, along with the changes apart from Clean C1/L2.

Total usable combinations for the alternate mod:

Green - 4
Amber - 40
Red - 40

(4) switches would be all that the alternate mod would require, unless ofcourse a cold-clipper was desired, in that case, then (5): High SPL, Main C12, R15, Peaker II, and Peaker III.

(Superceded.)

With this mod, the Clean channel is useable in all combinations, as are the drives. Only will Peaker III need to be disengaged whenever employing the Clean channel, that is, if the owner elects to forego the relocation of that signal's inject. Furthermore, the Clean will loose some highs due to the relcoation of C18. It is my recommendation that the Clean signal inject be relocated in order to enjoy the full potential of the mod.

NB: With Main C24 removed, C12 can be made bigger for the Clean. This may be desirable for single-coils. Simply repurpose the vacancy of C24 to fit in an additional polarized cap between the drain of TR2 and the cathode of V1B. 2u2, etc., to compound with the recommended 1.33u in C12. Or 4u7 dedicated to Clean for C12, and no bypass cap for drives might serve as an option for those who can dispense with extra toggles and so forth.

Cheers

 

[Vesperado]

Overlooked something in Phase III.

I need to readdress voltage at the primary. 120 VAC seems to be the maximum allowable operating line voltage for both mods. Reason is, DC filament line to V1/2 produces an higher filament supply in contrast to the AC supply. After a few conversations with a few tech-savy individuals, filaments should not exceed datasheet specifications, but 5% is considered by some to be "allowable".

Your amp may produce different results from mine, so check your filament voltages to ensure you do not exceed specifications. You may need to regulate your line supply.

V1 Pin 9/4: 6.59 / 6.64 VDC
V1 Pin 9/5: 6.56 / 6.65 VDC
V2 Pin 9/4: 6.59 / 6.66 VDC
V2 Pin 9/5: 6.56 / 6.67 VDC

120 / 121 VAC PT primary, respectively.

Filament volts should not exceed 5%, or 6.615 in this case.

Power transformers vary in specification and behavior. The Axiom is a stiff supply with very little sag, I'm informed. Due to its stiff regulation the screens would be over-stressed if (a) filament voltage is excessive, and (b) plate voltage exceeds 470 V or so. Because both the screen-grids and anodes share a common supply on the TSL-100, juicing the primary might become a concern once you fit an Axiom. The best solution to evade the associated problems with a common rail would be to fit a PT which provides a separate screen supply. So in effort to keep the engines running cool, I might reapproach the B+ rail, and might need to revamp the bias circuit, all depending, in effort to prolong the serrviceable life of internal components, as I do not currently know who would be able to provide a more fitting PT concerning screen regulation. One thing about the Axiom, in addition to its excellent regulation, that I like is that the filament supply is wound to produce less than 6.3V at 115 VAC, to allow room for 120+ VAC situations. At 121 VAC, my two-by-push-pull get 6.4 VAC. No worries there, yet the DC supply forbids 121 VAC on my current setup. I'm glad to know that now.

I cannot negate the tonal improvement acheived with higher potentail across the preamp plates. It was suggested that I could set the line at 115 VAC and lower the series drop-down resistance following the power section. I have a few 3w wirewounds withwhich I might try. At the momenent it seems to me to be more feasable than obtaining a special order tranny. Probably better for the power section, as well. That way she's cool, quieter, and still toneful. Sounds like a good idea to me.

Another idea suggested was a Mosfet regulator following the power section with a variable output. This would require a separate board and cutting traces, etc. It would afford the preamp section a fine-tune adjustment for overall tone, and a fairly quick adjustment. But to me this might be more troublesome, for it would doubtless invite addtional points-of-failure into the already stable and well-regulated supply. The advantage, however, would be a quick adjustment dependent upon the line supply. Still, I think a variac can perform that duty just fine.

At any rate, its gonna require some more tunning, the painful way, with trial and error. I will revisit R62 for starters. I believe that V1-3 is balanced already. I will rebias for both 115 and 120 VAC. I will report my findings.

Stay tuned.

 

[Vesperado]

Rebiased the amp. With the current set of E34Ls I am able to lower the screens a little closer to the recommended "lower than 470 V" operation:

V5g2 466 / 483 VDC, 8.395 / 10.336 W
V8g2 466 / 483 VDC, 8.448 / 10.983 W

115 /120 VAC, respectively.

That's below 18 watts combined at 115, and, below 22 watts combined at 120; about a four watt difference in total power output into an 8 ohm load.

Tonally, as it was around 26 watts previously, the lows are not as powerful as before. Still sounds good, nonetheless. Once I get a new pair in there, not too long hence, I will see if I need to adjust some values in the bias circuit or no (I'm not gonna fuss over a few additional volts with the current set). Or, perhaps replace the 1k drop-downs with 1k5, like the JVM...

I tinkered with R61/62 some more. Really not worth the fuss. My ears are happy with where they are at. And although I was able to squeeze out about 8 volts more with V1/2, the tone degraded due to the increased gain in those early stages. V3 has a large impact on tone as well, and where I have the line balanced now seems to work best. I suppose every owner out there could audition different values for themselves, that way they can match their style for the better, but what I have dialed in seems to fit a wide range of styles better than the stock values ever could. NB: I tried different tube sets in the preamp for the current config, the tone didn't change much other than more or less bass/treble, but they all sounded good and responded exceptionally well to picking dynamics.

When modding your amp, its a good idea to run a diagnostic with your multi-meter to see what your limitations will be with the tubes which you have fitted. I also highly recommend a variac to set your line volts at the primary, one with a backlit readout, that way you are assured to a degree about the expected performance of your amp. Now you could dispense with all this, provided you are assured about its operation running off the wall. In which case, give your amp a safe buffer, a fudge-factor, of a few volts, as line voltages from the wall swing from time to time.

This stuff didn't bother me much, that is, before tube prices sky-rocketed. Every tech-savy person has his own view upon "allowances", so I will not beat a dead horse; its up to the owner whether or not its that concerning. For me, atleast, it now is. And though I might consider it a compromise for that glorious HIGHER VOLTAGE tone, its a safer-less-hassle compromise that puts my mind at ease from various "what-if" scenarios.

[...sings Boston's "Cool the Engines"...]

 

[Vesperado]

Fitted a JJ 5751 into V4. It lowers the output just a little and sounds a bit smoother than the LPS, adding a bit of bass and rounding off the highs. Very pleased with it in there. Sort of auto-corrects the cooler power section tone-wise, restoring the bass loss from the rebias. Nice.

After a few weeks of auditioning all possible configurations, some really stand out. I can get Krank-ish tones, Uberschall-esque tones, Boogie-esque tones, Trainwreck-ish tones, Plexi tones, and some good in-betweens. The volume of the axe, pickup config, etc. hold a close relationship with the feel and texture of the amp. Highly interactive indeed.

The peaker(s), when engaged, boost the following stage(s) in amplitude. The only feasible way to lower output on the modified amp is selecting a lower-mu tube for V4 (preferred), set a lower line voltage at the primary, VPR (tone "sucker"), use a single speaker instead of four, single-pair power section instead of dual-pair/quad (preferred), bias it cold, or (maybe?) employ an attenuator(?). I shrink from the last, but it could be an option, I suppose. Why not sit 50 feet away? Also an option. Feeding the primary 115V is ok, but the tone gets "colder", if that makes any sense. Bottom line, this is not a bedroom amp. "1 1/2" on the volumes and you can rehearse with a drumkit no problem. Ofcourse, leaving Peakers II/III disengaged one could acheive bedroom levels. Then again, VPR will work fine at the expense of darkening tone.

Someone out there might be thinking, "well, I'll just attenuate the peakers with a series resistor in the path post-peaker". I'm not saying that you couldn't, but doing so and you immediately loose those lovely harmonics gained with, well, that additional gain. Marshall did that with the gain shape/pre-emph. circuits with the JCM2000 line, and although they do provide for some attenuation, they loose harmonic content otherwise presently available. The Jim Marshall Product, Ltd. designs did no such thing, and those amps are renown for their harmonic overtones. They are also notoriously loud. To me, a stock JCM2000 sounds overly processed and stale, or anemic if you would. Then you read of guys recommending to place active EQs into the loop, etc. etc. Yet, all this can be dispensed with simply by accepting the tube amp for what a tube amp does: loud. And it does loud very good.

I believe the only thing left for me to do is install a chassis fan to expell the air from inside. The DC rail rectifier was misplaced, and generates a fair amount of heat. The two wirewound resistors could be repositioned to the top of the chassis, maybe next to the PT, then again, its heat would likely transfer to the surface of the PT. I like a cold PT. So perhaps a small fan would indeed suffice.

I'm presently contemplating on uploading a video showcasing the amp, yet I am still auditioning some other values before I finally close her up for good.

Stay tuned.

 

[Vesperado]

Should be the last updates:

(Superceded.)

Enjoy!

 

[Techdeth]

This is awesome

 

[Kitchensinkelectronics]

Hey Again! Merry Christmas! I'm starting with your "merged alt mod. One question about pots. You suggest replacing Crunch Gain pot with a A300K, is that important? would like to stick to the same pcb mounded if possible. The B250K(lead/Crunch VR3) is available in the right form factor and going to be changed. I'm just a few final steps from stitching this Frankenstein lady up again and start recording.

 

[Tatzmann]

Here is another dude going nuts on his TSL.
Lots of info.

http://anchorstates.blogspot.com/2009/01/amp-guts-complete-marshall-tsl-mods.html?m=1

https://www.tumblr.com/atomiumamps/9124750245/current-complete-mods-to-europa-marshall-tsl-100

 

[Kitchensinkelectronics]

Stared with his mods (defenetly a inprovemet from stock) but couldent resist the urge to go even deeper down the rabbit hole when I found this thread. The amp is sounding way better hopefully I’ll be done soon.

 

[Vesperado]

Hey Again! Merry Christmas! I'm starting with your "merged alt mod. One question about pots. You suggest replacing Crunch Gain pot with a A300K, is that important? would like to stick to the same pcb mounded if possible. The B250K(lead/Crunch VR3) is available in the right form factor and going to be changed. I'm just a few final steps from stitching this Frankenstein lady up again and start recording.

If you want more gain on the Amber, then yes, A300k will get you there. Bourns make them: drop in replacement, along with the B250k. Another trick would be a switchable resistor in // with the gain pots for a low gain option which might help dialing in precise break up. But I didn't find it necessary, there is good control as is.

 

[Kitchensinkelectronics]

Happy new year! Tinkering with the amp again. Did a lot of your suggested mods except the peakers /saving that for later if needed. Did the mod on the clean channel with the relocated insert. I have been having problem with hum on the clean channel and bleed(sound even when gain and volume set to zero on the clean channel). The hum was associated with the volume not the gain pot.

The problems were present even befor the mod but now it’s worse with really low output and hum(turning up volume just introduce hum) . The crunch and the lead sounds glorious really love the amp now. Any thoughts were I would start trouble shooting? I’ve looked at the clean board and followed the connection from the clean volume pot through the OD board to the main board. Preamp tubes all new all electrolytics are new, volume pot changed.

 

[Vesperado]

Happy new year! Tinkering with the amp again. Did a lot of your suggested mods except the peakers /saving that for later if needed. Did the mod on the clean channel with the relocated insert. I have been having problem with hum on the clean channel and bleed(sound even when gain and volume set to zero on the clean channel). The hum was associated with the volume not the gain pot.

The problems were present even befor the mod but now it’s worse with really low output and hum(turning up volume just introduce hum) . The crunch and the lead sounds glorious really love the amp now. Any thoughts were I would start trouble shooting? I’ve looked at the clean board and followed the connection from the clean volume pot through the OD board to the main board. Preamp tubes all new all electrolytics are new, volume pot changed.

Glad to hear you are enjoying the drives

Peakers II/III open up a whole new level of tone. The amp still retains that Marshall character, but the versitility expands like none other. I'm sure when you build up some confidence you'll be happy to have ventured there.

As for the hum, I'm not sure what might be causing that for your amp. I know Marshall made a change sometime in the early 2000s from photocoupler switching to relay switching. That might have been a reason for the change, yet I couldn't say with any real certainty. My amp likewise suffers from some hum, but I've been so accustomed to drowning it out I've never really bothered to try and narrow down the culprit. Probably need an oscilloscope and tone generator for that, which I don't have.

With all the nonpolar caps separating the Clean circuit from chassis ground, it wouldn't surprise me that some residual AC is "jumping the fence" as it were. Likely just a design flaw, the TSL is in no wise perfect, and its a PCB nightmare to boot. I thought I had killed the hum over the FX Loop once, but then a few months later hum appeared over the FX Loop again. It is what it is. Wish I could be of more help.

 

[Vesperado]

I'm close to finishing up another revision as I haven't revisited the Tone Shift mode since the time of adopting the cascading peaker scheme. The tone stack works good for no peakers as is, but after a good month of auditioning various pedals, configurations, etc. I've determined that there is still room for improvement. Suffice it to say that I have successfully removed the mid freqq. "compression" and opened up the bass freqq. on the Crunch; just need to verify the changes on the Lead. The Normal modes are left to stand.

Having ran some figures through DTSC, I noticed that my slopes are too steep and that my mid cF is too far right. This becomes audibly apparent whenever employing the peaker cascade irrespective of the configuration. Upon recalculating some figures, I've been able to remove the mid freqq. conjestion, also remove the restriction upon the bass, yet retain the "Treble" cF. Having it too far right is unpleasant. So now I am happy to report that the Bass knob tailors Bass, the Mid: full Mids, and the Treble: high mids and up. Before the Bass controlled low mids, the Mid: a notch thereof, and the Treble: high mids and up. The tone previous to the fix was rather squished and somewhat of a one-trick pony. The Deep is more effective with the changes, to boot.

The immediate benefit with the change is the ability to employ a broader range of boost pedals with the peaker cascade. The tone can be described as more "modern".

Another discovery made was that the factory had varying tolerances for each 470k signal attenuator resistor. Crunch R6 was 6k low, Lead R44 5k low. This is an issue for tone as higher freqq. escape the attenuation more than the low freqq., especially as this resistor creates a joint load along with the Treble and Low pots. The solution? Make them a solid 470k. Doing this will restore the low-end wanting in what otherwise would be a mid/high heavy signal. A key component in servicing your amp! Do not overlook this!

Found a more suitable place for the Global SPL Bleed. Having it before the FX Loop attenuates those higher freqq. for any effects. No good.

Restored the value of the Clean channel signal attenuator resistor to 470k in effort to match FX Loop level to unity. And on that note, reduced that gain stage a tad to keep everything as close to unity as possible: 33k > 30k. For those wanting to have the FX Loop boost your signal for solo work, why not install a 50k trim pot in that place? A 30k + B22k trim pot will get you there, too. Options. Options...

 

[Vesperado]

It's been a hard effort, but the reward was well worth it: I have a great sounding Marshall now--one that sings to me at that!

(Superceded.)

I've tried not to depart too much from the amp's topology, albeit in some places it was rather unavoidable. With this last revision the amp can handle boost pedals in a stackable configuration while employing cascading peakers. The bass has been opened up in the low-end, the values tuned to make the speaker(s) resonate naturally in all configurations. Volume management has been improved as well. This means that bedroom level can now be acheived provided the mod be followed in full.

I have reserved to provide a toggle-switching scheme, as it should be rather self-explanatory for those who know what they are doing.

The amp produces an immense range of tones from Plexi to Uberschall and beyond, from classic to contemporary, and can be ran via a variac up to 120 VAC. The only real caveat is that the Clean channel is rather selective in how the selections are made among the toggles, what axe, etc. and the only work around for that would be a make-shift auxilary relay-based switching system hard-wired into various places to assign its separate values. I designed the Clean for cleans, although it can take effect pedals very well, understand it is not much suitable for boosting.

Aside from that, all in all, its an amp which breaths fire, a full-grown Lion unleashed from unwelcomed captivity with one view in his surveying eye: to maule. This amp arms one with full-brute authority and still it conforts one with bell-like jangle and shimmering cleans to ease up a worried mind. Either way you set it, it delivers.

I am confident it will please

 

[Vesperado]

Boy, oh boy. I think I have stumbled upon a solution to a problem inherent with the design regarding the Clean channel. Waiting on parts to verify the change. Standby to standby...

 

[Vesperado]

.