12-Series Build. UK Suppliers. Would 50w do the job?

[OdgeUK]

Hi

I think I'd like to build a '68 12 series Superlead, to the 'VH Specs' which were revealed by John Suhr some time ago. The aim is to own a build to join my other stock JMP Marshalls, but for it to be solely for getting a VH tone. Cos I think everyone should have a 'Van Halen amp'

I'd like to do it on the cheap. By that, I mean I don't care if it's not 100% accurate in terms of materials, suppliers and parts, just as long as the circuit is correct and the Chassis and Board holes and layout allow me to follow the various published layout diagrams.

I also don't mind collecting the parts over a long time, if it means getting the build cost right down by shopping around.

I already have a 1980 100w JMP empty head cab that I can stick this in.

One problem is that most of the kits or parts suppliers for these things are US-centric. I'd like to think I can get everything I need here in the UK from regular electronics suppliers like RS?

Also I am contemplating building it as a 50w '68 as it would further bring down the cost and complexity of the build. All my current Marshalls are 50w. I know the VH tone has already been 100w concentric but even Dave Friedman thinks his own personal '68 50w is his benchmark amp for that tone. Does a 50w sound reasonable and how would the 'VH Spec' translate to a 50w build?

[OdgeUK]

This could be a good start?

http://www.ampmaker.com/store/Turret-bo ... tag-board/

[neikeel]

You have few options.
Cheapest would be to buy a running amp like a Carlsbro PA60 for £250 with Drake trannies and choke. You could use the chassis and trannies, sockets etc and simply add a new circuit board with your choice of parts.
Other option is to buy one of these:http://www.ebay.co.uk/itm/JTM45-replace ... SwgZ1XtyCQ and get your bits gradually.
You could always send me a pm as I have a spare 50w Valvestorm chassis with original Drake end bells and quite a lot of spare parts you can have to start you off. That way you could spend your money on important things like the transformers. I also have a pair of 70s Dagnall 100w transformers too, but no spare chassis for those.

[OdgeUK]

Great, thanks Neil. Was going to PM you just before I decided to post here as I had a feeling you'd have some pointers!

What do you think about Classic Tone or Mercury Tx ?

[neikeel]

Personally I would only use MM in a modern high gain setting. Generally I use originals or clones from George (historically) and Brian Wallace at Marstran. Quite a few people seem to like the Classic Tone iron. I am a bit weird (there I said it) but if I am building a Marshall clone I want the wiring colours to be correct so when someone needs to work on it in the future it will be very straightforwards and lots of the classic tones have weird wire colours. Brian did have some special 50w trannies wound to match the Dagnall C1998 tones from a 68SL, don't know if they hit the mark or not.
Offer on the parts still stands.

[Littlewyan]

Modulusamplification.com will have all the parts required to build a 50W Marshall. He makes amazing faceplates and is very helpful. A 50W will do you just fine. Get an attenuator.

[neikeel]

Modulusamplification.com will have all the parts required to build a 50W Marshall. He makes amazing faceplates and is very helpful. A 50W will do you just fine. Get an attenuator.

He already has two 50w Marshalls, and I do not think that they will be much different to a 68 spec, but there is only one way to find out.
Yes I have found Modulus very helpful too.

[Littlewyan]

Ah yes I see. I would think the 73 1987 should get him pretty close. I guess the 68 might be less aggressive as the preamp distorts a bit more and the filtering is lower. I don't think it will be a world of difference though.

[OdgeUK]

My expectation, perhaps naively, from a dimed or heavily attenuated 68 circuit was something like this (which is really pretty far removed from the current tone of my 73 and 78 50watters). I know this is a '74.



Apparently it's Stock and has a Dagnall C2668 OT

[Littlewyan]

Hmm what is the spec of your 73 JMP?

[OdgeUK]

Hmm what is the spec of your 73 JMP?

Stock 73. LarMar PPIMV added. One of the last handwired. 416v-418v plate voltage last time I checked with a Bias Probe.

I'm reluctant to post this as it's mindless noodling littered with crappy playing, but this is a clip of the '73 a few years ago. Volume full but 16db attentuated and with the PPIMV engaged at least a little (I think). I love it, but it's not VH.




My 50w Build needs to sound like this stock 68:



My 78 50w also sounds amazing (375v on the Bias Probe), but it mostly sounds like the 73 but just significantly tighter in the low end with a bit more articulation in the gain. Both my 50watters do the Classic Rock thing exceptionally well, but neither would be the right amp to crank out "Mean Streets".

[OdgeUK]

Here's the same 68. Sounds incredible

[Littlewyan]

Hmmm it might be that you're using G12-65 speakers. VH uses G12M speakers. You get a bit more snarl out of them. That will be why your amp sounds tame. G12M Heritage speakers will do you. Also I found that you can lose a bit of gain with the PPIMV turned down just a tiny bit. Never under estimate how much difference speakers make

[Littlewyan]

Also is that with every control on 10? Minus the normal channel volume.

[OdgeUK]

Hmmm it might be that you're using G12-65 speakers. VH uses G12M speakers. You get a bit more snarl out of them. That will be why your amp sounds tame. G12M Heritage speakers will do you. Also I found that you can lose a bit of gain with the PPIMV turned down just a tiny bit. Never under estimate
much difference speakers make

I did go down the speaker rabbit hole a few years ago, nearly tore my hair out with A/Bing. I settled on the G12-65s as they smoothed bright amps at high gain (I actually gig with a Peavey JSX running pretty high gain). I do agree that G12Ms are a significant part of the VH sound...those gnarly mids is instantly recognisable. However I tried couple of Greenback variants (G12C, G12-65M, Tayden Brit60) and hated the fizz and the ice pick highs on single notes.

The 68 in these clips feel like there's almost another gain stage or cascade though!

Did a bit more research, there's a whole thread on this 68. The YT video says it's stock but in the thread, Pleximaster states that it was heavily modded on purchase and rebuilt. Be interesting to understand how 'special' the C1998 OT is in it and what a good aftermarket equiv would be.