Beginner Help!!!!!

[aryasridhar]

Hey Guys,

This is my first post here, I am new in terms of posting on this forum, however i have been an avid reader of the forum, and the wiki, etc etc, amazing site and really great information....

So i have decided on making a JCM 800 2204 clone, I want to go with the circuit layout of Metro Amps, I compared both Ceriatone and MetroAmp Layouts that i could find, and observed that these are almost same, in terms of the components on the board.....There are a few additional parts here and there on the Metroamp layout....

However i would want to get the chassis, front and back plate and other hardware from ceriatone as that works out cheaper to me....

I would however need complete instructions that are needed to build the amp, which i was unable to find on the metroamp site...

Could someone please help me out with the BOM and other instructions that are required please? I would greatly appreciate that...

Also wanted to know which transformers would be good? Heyober, ClassicTone, Hammond or Mercury Magnetics? I think Hammond is the least expensive, and MM is the most expensive, so i would like to go for something in between maybe.....I am unsure which specific part numbers of the respective companies i need to go for, hence would need that information too please......

and anything else that you guys feel i must know before i start the build.....

This will be my first amp build, I am very much familiar with electronics, and i also build custom pedals here in India....have sold quiet a few as well.......so soldering, part alignment, polarity etc etc are not an issue.....

Any help is greatly appreciated.......

[demonufo]

Actually the metroamp layout has a few wires missing here and there, but these are pretty easy to figure out. There is a purple NFB lead missing (same as the 1987 layout) a couple of pink wires missing from the tone stack (again, same as the 1987 layout) and a link lead missing from the top right terminal of the input jacks to (I think, from memory) the bottom left terminal of the input jacks.

IIRC, these are the only things missing though.

You won't find full metroamp instructions specifically for a 2204, as there never was a metroamp 2204. You'll have to follow either the 50W 1987 instructions on the wiki, or the 2203 instructions as best you can, and adjust to suit.

Mercury Magnetics should be right out of the picture, IMO, if going for authenticity. They might be nicely built, and expensive, but built better does not necessarily sound the part. I'd just go for the Metroamp transformers which are available from Heyboer. You may want to think about an extra B+ dropper for the pre-amp, depending on which era of 2204 you want to go for.

[aryasridhar]

Actually the metroamp layout has a few wires missing here and there, but these are pretty easy to figure out. There is a purple NFB lead missing (same as the 1987 layout) a couple of pink wires missing from the tone stack (again, same as the 1987 layout) and a link lead missing from the top right terminal of the input jacks to (I think, from memory) the bottom left terminal of the input jacks.

IIRC, these are the only things missing though.

You won't find full metroamp instructions specifically for a 2204, as there never was a metroamp 2204. You'll have to follow either the 50W 1987 instructions on the wiki, or the 2203 instructions as best you can, and adjust to suit.

Mercury Magnetics should be right out of the picture, IMO, if going for authenticity. They might be nicely built, and expensive, but built better does not necessarily sound the part. I'd just go for the Metroamp transformers which are available from Heyboer. You may want to think about an extra B+ dropper for the pre-amp, depending on which era of 2204 you want to go for.

I am looking at building one from the early 80's, in that case what are the things i need to look for?
I did find a schematic (http://home.comcast.net/~jbjdav26/2204r16.JPG" onclick="window.open(this.href);return false;) on the SDM site....is this good to follow ahead for the build?

Could you let me know which era is this from? the SDM layout?

Thanks a ton for the response mate......The Marshall tone is my dream, please help me out on it....

[demonufo]

Aha, now Steve's layout (SDM) isn't really like any production 2204 at all... but that's NOT a bad thing.

You'll notice the filter on the preamp is lower than the 50/50 normally fitted. And the screens and the PI are also lower filtering. This will make for a smoother, bouncier amp, and may be to your liking. It is less tight and aggressive than the JCM800 versions.
It also has the older type presence circuit, which was only used on the earliest of 2204's. It is, however, a nicer operating control, but it is slightly scratchy in operation by it's very nature, due to there being DC present on the pot. This is why Marshall changed to the later style 22/25K version as seen on the metroamp layout.
Originally, the JMP and early JCM800 versions would have had a lower voltage secondary on the power transformer, giving you somewhere between 360 and 400V on the plates of the power tubes. Somewhere around '82, so say, the transformer spec. changed (although the pt. no. remains the same) and the plate voltage would be closer to 470. These amps are a little cleaner, and more aggressive and ratty sounding, in part down to this, but mostly because the voltages are run a bit hard on the pre-amp tubes. Most people would have put another B+ dropper in to lower the voltages for the preamp tubes.
Then there came slight further changes in mid 1984, but these are minimal, and only really affect filtering, and the layout of the PCB (although a capacitor across v1 to stop potential oscillation was also added - but shielded cable on the inputs is a better way to do this, imo)

Steve's layout is certainly one of the better ones out there. Just not accurate to any 2204. But like I said, this is NOT a bad thing.



Unless you've already experimented with 2204's, and changed a few things here and there, you'll probably never get it quite right first time. But they are simple amps to change and experiment with.

[aryasridhar]

Aha, now Steve's layout (SDM) isn't really like any production 2204 at all... but that's NOT a bad thing.

You'll notice the filter on the preamp is lower than the 50/50 normally fitted. And the screens and the PI are also lower filtering. This will make for a smoother, bouncier amp, and may be to your liking. It is less tight and aggressive than the JCM800 versions.
It also has the older type presence circuit, which was only used on the earliest of 2204's. It is, however, a nicer operating control, but it is slightly scratchy in operation by it's very nature, due to there being DC present on the pot. This is why Marshall changed to the later style 22/25K version as seen on the metroamp layout.
Originally, the JMP and early JCM800 versions would have had a lower voltage secondary on the power transformer, giving you somewhere between 360 and 400V on the plates of the power tubes. Somewhere around '82, so say, the transformer spec. changed (although the pt. no. remains the same) and the plate voltage would be closer to 470. These amps are a little cleaner, and more aggressive and ratty sounding, in part down to this, but mostly because the voltages are run a bit hard on the pre-amp tubes. Most people would have put another B+ dropper in to lower the voltages for the preamp tubes.
Then there came slight further changes in mid 1984, but these are minimal, and only really affect filtering, and the layout of the PCB (although a capacitor across v1 to stop potential oscillation was also added - but shielded cable on the inputs is a better way to do this, imo)

Steve's layout is certainly one of the better ones out there. Just not accurate to any 2204. But like I said, this is NOT a bad thing.



Unless you've already experimented with 2204's, and changed a few things here and there, you'll probably never get it quite right first time. But they are simple amps to change and experiment with.

Ohhh, Thank you for the info man, I am really considering building one which is authentic.....that's the reason why I am going for the build as honestly buying a real Marshall and getting it to India is not really feasible for me. Hence i want to recreate the original as much as I can....

Is the Ceriatone JCM 800 2204 HW layout close to the original? I can follow that if it is.....

It would be great if you could help me out with the layout/instructions if any to start my parts purchase please? and also anything else that I may need to be aware of....

Thanks again for all the help man......

[aryasridhar]

Any more inputs please!!!!!!

[neikeel]

Build one as per SDMs layout.
It will work, it will sound good.

The only limiting factor will be the quality of parts that you use and how good you are at putting it together properly.

If you really want to go original 2204 spec I can sell you an original fully loaded Marshall board

[aryasridhar]

Build one as per SDMs layout.
It will work, it will sound good.

The only limiting factor will be the quality of parts that you use and how good you are at putting it together properly.

If you really want to go original 2204 spec I can sell you an original fully loaded Marshall board

Ahh, that sounds interesting....how much for the board? any pics that you could share?

[neikeel]

I am at work at the moment, but if you are serious I can take some pics at the weekend.

[aryasridhar]

I am at work at the moment, but if you are serious I can take some pics at the weekend.

Yes I am serious.....

[6burgh]

You should also consider trannies from Brian Wallace (marstran) or Chris M****n (m e r r e n), both of their trannies are tops.

And btw, when Neil show pics, pay attention!

[aryasridhar]

You should also consider trannies from Brian Wallace (marstran) or Chris M****n (m e r r e n), both of their trannies are tops.

And btw, when Neil show pics, pay attention!

Sure, will check the trannies out, and sure will pay attention to the pics....

[jimmyride]

I was reading "Behringer Help!!!!!!" I was like... "dude, nothing can help you"

[aryasridhar]

I was reading "Behringer Help!!!!!!" I was like... "dude, nothing can help you"

LOL.....I sure don't need help with Behringer LOL

[ams1aw]

WELCOME to the Metro Forum!
I'm ams1aw from Austin Tx. I just wanted to add 2 cents to help you with your purchase decision.
After 21 years of Aircraft maintenance/QA/micro-mini, I decided to take a crack at building some of these wonderful amps.
I started with a 2061, then a JTM45, then 1987, then decided to just BUY a few 12000s. So far I've owned 2 Blockheads, 2 of George's builds, and now a 12000 w/MOD 5 that was built by Skip Sims at British Audio, Nashville. Look at the new postings for British Audio 12000 w/mod5 on this forum. I HAVE HAD NOTHING BUT HELL WITH THIS SKIP SIMS / BRITISH AUDIO AMP!!

Anyway, I have found it is a LOT EASIER to just buy a brand new build from a builder who will offer a great return policy/warranty period.

The reason I say that is because of the HELL I HAVE HAD trying to figure out why the amp I am building will not fire up and "fly right". Even after following the instructions to the letter, I have had SO MANY PROBLEMS with amp builds! Mostly because of incomplete instructions or brand new parts (like brand new but defective rectifiers and Mercury Mag transformer wiring) that are not covered in the instructions. Believe me, after 21 years of fixing Naval Aircraft, do you think I might how to follow written instructions?

Then, when you post questions here, you get mostly smart asses or grammar police who only answer your pleas for help by implying you are stupid or too lazy to look through the THOUSANDS of post to find a little help! The search feature sux too, by the way, but you probably already figured that out, right? You have also figured out that no one wants to help you here. I saw your plea for help and felt sorry for you because I have been there.

Most of these guys have the "I have the knowledge. Good luck getting yours" mentality. You will also find most of the posters are extremely brave hiding behind their firewalls. They will be totally beligerrant (sp?) to you. But, what can you do if you need the info?

One good thing though! The more headaches/problems you have, the more you LEARN right?

If you want to learn, buy a 2204 kit. If you want NO PROBLEMS/HEADACHES just buy a brand new amp.

I am here for you bro! I GOT YOU. I am a senior member but I am a junior builder, hehehe!

I will help you the best I can. Just pm me or reply okay?

By the way, I am VERY SORRY I have never had the opportunity to travel to India. I have been around the world numerous times on Navy Aircraft Carriers and Naval Air Stations but the closest I've ever been stationed to India is the Indian Ocean patrolling the Straight of Hormuz (sp?) mostly. Also been to Diego Garcia and Pattaya Beach, Thailand.

Anything I can do don't hesitate okay bro? -JD, USN(RET), Austin Tx.