Why vintage Marshalls have more balls

[Littlewyan]

I've watched various videos of old Marshalls and new Marshalls and it seems the old ones always have more balls. Its very clear in George's video comparison of his 67 Superbass Clone to the original that the original has more gain and just seems to have more bite. When he hits a big open E he gets a lot more snarl out of the original.

So I've been trying to work out why this is as I think my JTM50 is a bit too polite sounding at times. Is it the valves? The capacitors? Looked like George was using NOS caps in his replica along with Carbon Comb resistors in the correct places. I know the pots are often higher than spec in old Marshalls but not massively.

Any ideas?

[RockinRocket]

A few things come to mind. One and maybe the most important is the age of the amp. They tend to always sound different. Second would be the grade of the steel in the transformers. Do Georges match those of the originals? Third would be parts. Ive seen Metos with full sets of carbon comps and that would change the tone especially on the plates and Marshall never used CC on the plates Afaik. Pec pots are carbon element and need to be CC. ect.

[Littlewyan]

Yeah I know that due to wide tolerences all old Marshalls sound very different, but they all seem to have that snarl.

Transformers could be it. I'm using Classic Tone in my Marshall which do seem to have a bit more bass than other makes I believe. Going by the sound clips om their site.

I wonder if swapping my tonestack silver mica for a 270pf Ceramic Cap will help. Unfortunately I can't find any vintage ceramics on Ebay . Not overly keen on using a new ceramic as they tend to either be tiny or blue which sticks out like a sore thumb.

I think installing CC is a waste of time as they were only used in a few positions and this isn't consistent anyway. I've seen Marshalls with both CF and CC in the NFB position, both sounded just as good.

[RockinRocket]

I think most folks building clones are chasing unicorns really. Youll never be able to match that old amp.. no matter how many old correct parts you collect. I forgot to ask if that original Bass still had the original electrolytics? If so I doubt they still hold the same capacitance as when they left the factory.

I'm not a huge believer of two amps sounding much different. If you can hear such a drastic difference the little 5% tolerance from resistors can make I don't know what to say. I think more of the difference is the position of pots as they are variable and not consistent from one to another or potential differences in windings of the transformers. Todays amps sound identical to my ears.

[Littlewyan]

I don't know if it had the original electrolytics. I do remember reading actually that George often finds original resistors in old Marshalls measuring on spec. I was under the impression that some were wildly out of spec. I guess you're right, it probably is the pots. Also I don't know if George had NOS Mullards in his replica. He didn't say he did so I'm guessing not. I just noticed that his original Marshall had more detail in big open chords and more gain. Both could be contributed to the valves he used.

[RockinRocket]

Are we talking CC resistors being out of spec? I'm tryig to think what spot of he circuit would have more gain with high drifting CC. Cathodes would have less gain if drifted high. Same with the 100k on the cathode follower if that even was CC. 470k mixers drifting high might add a touch more gain. Plates were never CC and that would probably be the reason if they were CC. The only spot left would be the b+ droppers drifting higher and that certainly would account for a bit browner tone.

My original has almost all Iskras and they measure no different than Iskras sitting in a bag for the last 40 years. Usually slightly above value but way under 5% when measured in circuit. The CC in the B+ were the only ones slightly higher than tolerance.

[Roe]

resistors don't drift much in marshalls. most plate resistors are CF and the few CC resistors have extremely little voltage drop over them. Filter caps always vary, as does pots

[shakti]

The pots are a big player in how they sound, from my experience. My builds have always used all the NOS parts I could find - mustards, RS silver micas, Iskras or Pihers, and the best repro transformers. I've written about it before, but I've found that vintage pots add a certain something. It's particularly boticeable in the tone stacks. It's actually no wonder as the older pots have a different taper, overall value and maybe a different composition too. It all adds up to a slightly different EQ with more of a warm mid hump and less low bass.

[coldengray]

I've directly compared two JTM45s I've built using a Metro Headmaster:

- One amp with almost all NOS parts including a vintage RS OT.
- One amp with MM PT/****** Drake OT, mostly modern parts except NOS mustards.

The tone was surprising close, it surprised me. I haven't been able to compare a vintage JTM45 with either.

[Littlewyan]

So maybe its the pots rather than the resistors. The pots do seem to vary a LOT in old Marshalls from what I've read. For a start the treble and middle pots I think are often log pots when they're meant to be linear and the values tend to read higher. Volume pots measuring at 1.3Meg, Treble Pots reading at 300K and Middle pots at 29K. So I guess that could cause it. The higher value middle pot could definitely give more gain.

Shakti have you got a link for your thread regarding the pots?

Coldengray - Did all NOS parts measure on spec? Particularly the pots?

[RockinRocket]

The old pots should be CC so them drifting would make a lot of sense.

However, playing with Duncons TS calculator and drifting the pot values up only really adds 1 db of gain while the frequency spectrum stayed ruffle the same. Is that enough to explain this? 1M to 1M4. 25k to 33k. 220k to 300k

[coldengray]

Sorry, I should have mentioned the pots were PEC in one and CTS in the other. I haven't had good luck finding vintage pots...if anyone has a stash and is willing to part with some, please let me know.

[Roe]

treble pots often read around 330k, mid around 33k, bass and vol around 1300k, presence 6,7k roughly

[Littlewyan]

Does it make more of a difference if you set the bass pot to 0 and the middle to 10? I only ask because the tonestack is very interactive and certain pot values may make more difference when the EQ is set like this . I would check myself but I don't have access to the TS Calculator at the moment.

Quite tempted to open up the middle and treble pots and lightly sand some of the material away to bring the values up a bit......I'm sure I measured my middle pot and it was 24K .

[Roe]

the tone stack calculator has the wrong value for the PI impedance. its not around 500k, as indicated, it is way higher - at least 2M w/o NFB and as much as 4M with NFB