JCM 800 KIT?

[dd3keegs]

Hey. I've taken some of the forum member's advice and started small. My first build was a single channel Class A 5 Watt Hi Octane amp from AX84.com. I then built The same amp with and extra gain stage. Then moved up to Fender Tweed 5e3 clone. Now I think I'm ready for a JCM80O CLONE with an Extra Gain Stage and Depth Mod? Silly question...but does Metro amps sell this as a kit? I already have a empty Head cab with 2 matching Closed Back1 x 12 cabs loaded with Celestial Vintage 30s. I also found this wiring diagram online. Is their any other BOM or wiring schematics or diagrams that are better? ANY help would be appreciated. Thanks.

[danman]

Valvestorm sells kits that are based on the Metroamp kits and layouts. Here is the page for the 2204 which is the predecessor to the JCM800...http://valvestorm.com/2204%20Kit You basically build the kit from their 50watt checklist and instructions and add in the couple of extra bits that you need. The regular 50watt and the 2204 circuit are very similar except in the preamp. The 2204 has a cascaded preamp which gives you the extra gain. You do have to buy your own transformers which allows you to use what you prefer. The Metroamp, Marstran and Classictone trannys are all very good so it's up to you want you want to use. I will mention that the early 2204 circuit ran a much lower B+ (around 370-390vdc) than the later JCM which was up in the mid 400s. Some people prefer the warmer, earlier breakup of the low voltage model and some prefer the brighter, punchier nature of the later high voltage models. If you have any question, just email Valvestorm and he will get you the answers you need.

[danman]

I just noticed on the Valvestorm site, where they list the transformer part numbers from different manufacturers, they have the classictone PT and OT part numbers mixed up. The standard PT is 40-18089 and the OT is 40-18025. Classictone also offers the 40-18054 PT which has a high voltage secondary (450v) and also a low voltage secondary option (about 410-420v). This PT allows you some flexibilty in your final B+ voltage. Just be aware that the chassis that Valvestorm sells requires a laydown PT and not the upright style...http://valvestorm.com/Transformers#50watt

[danman]

I wrote all that and then realized you may want to build a 100 watt model instead of the 50 watter. Either way, they have what you need for the bigger amp also.

[dd3keegs]

Thanks so much. I've checked out Weber, Tritone and Mojotone. This looks like a good kit too.

[danman]

Valvestorm took over the amp kits when Metroamp stop selling them. He is also a member here so he can help with any questions you may have. Any of the parts on his BOM with the letter "M" beside them are what was used in the original Metroamp kits. You also have the option to order the vintage NOS parts instead if that's what you prefer.

[neikeel]

I think you will find the Valvestorm/Metro project a much better quality and more true to the originals than the other kits, most people get stuck half way through with the others and then toddle along here for help!

Build one true to the originals with correct wire colours. The Classic tone trannies appear to be good value but they have odd wire colours.

A 2204 is a very usable amp with great tone when set up properly.

[fixer2]

Hi I purchased the stuff from valvestorm to make there 100 master volume kit how much if any is this different than a JCM800 10” watt Marshall I know Marshall made jmp in the late 1977 or 1978 that were 100 watts and had a extra gain stage that the 50 didn’t until the 1981 JCM800 50 . I want to build a jmp 100 with a extra or two extra gain stages . We’re could I look for a layout or guidance.

[Asphaltbouncer]

Very cool idea.

[fixer2]

What would be a good out put transformer for my 100 watt Marshall clone of a master volume jmp/ JCM800 with a extra pre amp gain stage I have been waiting for a long time for a transformer and they are all out of stock what website and part number would greatly help

[danman]

https://www.mojotone.com/British-Style- ... ransformer

and
https://www.tubesandmore.com/products/t ... t-marshall

The Hammond # will be P-T1750U for the 100 watt OT

This is a link for Edcor. They make great transformers but they are normally custom made and their wait time can be 1-3 months. They do occasionally have some models in stock and ready so you may want to contact them first.https://edcorusa.com/collections/tube-a ... ransformer

If you buy a pre-punched chassis, you will need to verify the mounting dimensions of the OT to the mounting holes on your chassis. They don't always fit every chassis perfectly so you need to verify before buying. I usually purchase blank aluminum chassis and drill my own holes so I can use any transformers that I want.

[fixer2]

Thank you once again

[jack1999]

I wrote all that and then realized you may want to build a 100 watt model instead of the 50 watter. Either way, they have what you need for the bigger amp alsohttps://www.pneda.com/.