Thinking of diving into a 2203 build...

[Flight_of_Icarus]

Hey all,

So - as the thread title suggests, (and after some reading into a bit about it) I'm considering diving into a new frontier (for me)...building an amp! More specifically speaking, a 2203 copy.

It's something I've been curious about for a good while now, and I already have all the tools necessary for the job (good quality soldering station, good multi-meter with proper voltage capacity, all basic hand tools, wiring, heat shrink, heat gun, other measuring equipment, etc.). I do have some previous experience with soldering work on PCBs (of hi-fi equipment) and other basic electronics work, as well as general knowledge of components, so I wouldn't be going in completely blind - but I also want to make sure I'm being realistic...

I did manage to find the old instruction guide for the Metropoulos 2203 kit, and it seems like an excellent guide with very clear instructions and plenty of photos - enough so that going through it makes me feel more comfortable about attempting a build than before.

With that said, I did have the following questions for those of you who have built 2203/2204 amps..

1. Is it better to just buy a kit, or source parts from various vendors as needed? My ultimate goal is a replica of a bone-stock JMP 2203, with the exception of an FX loop addition. Valvestorm seems to be the one w/the correct chassis for this (because of the extra holes on the back, and cutouts for rocker switches), so that's why I was thinking of going the multiple source route if I did do this...

2. Turret board vs PCB - for someone primarily used to PCB work, will using a PCB make for an easier transition into assembling an amp? If so, which PCBs are generally regarded as the best options? (Cannot remember the brand, but I do recall seeing one that was very neatly labeled and looked well made - almost "idiot proof", if you will).

3. Other tips and advice?

Would greatly appreciate some input!

 

[neikeel]

My suggestion is get everything from Valvestorm, study his site first to make sure it’s the most accurate.
There is a seller on eBay from Germany that has dead on pcbs. I’ve used one on a combo refurb.

 

[David Copeland]

If it were me I'd go with a turret board, but that's just me. The complete kit would almost certainly be cheaper but buying parts allows you to go with premium components without paying for stuff twice. Good luck. Oh, it would probably be a good idea to hit the valve wizard site on grounding. The 800 had ground loop problems and its gain will potentially lead to issues.

 

[Flight_of_Icarus]

My suggestion is get everything from Valvestorm, study his site first to make sure it’s the most accurate.
There is a seller on eBay from Germany that has dead on pcbs. I’ve used one on a combo refurb.

In the interest of making sure I'm following forum rules (by not posting links), is it a seller by the name of marlinck?

I believe the other PCB I was thinking of is made by Sirius (in Australia).

If it were me I'd go with a turret board, but that's just me. The complete kit would almost certainly be cheaper but buying parts allows you to go with premium components without paying for stuff twice. Good luck. Oh, it would probably be a good idea to hit the valve wizard site on grounding. The 800 had ground loop problems and its gain will potentially lead to issues.

I'll check out Valve Wizard for sure.

A kit does seem like the cheapest route, but I do like the idea of being able to cherry pick parts to make it 100% how I want it to be (perhaps a habit I've picked up from customizing guitars to taste, and building PCs).

 

[Burk]

Hey all,

So - as the thread title suggests, (and after some reading into a bit about it) I'm considering diving into a new frontier (for me)...building an amp! More specifically speaking, a 2203 copy.

It's something I've been curious about for a good while now, and I already have all the tools necessary for the job (good quality soldering station, good multi-meter with proper voltage capacity, all basic hand tools, wiring, heat shrink, heat gun, other measuring equipment, etc.). I do have some previous experience with soldering work on PCBs (of hi-fi equipment) and other basic electronics work, as well as general knowledge of components, so I wouldn't be going in completely blind - but I also want to make sure I'm being realistic...

I did manage to find the old instruction guide for the Metropoulos 2203 kit, and it seems like an excellent guide with very clear instructions and plenty of photos - enough so that going through it makes me feel more comfortable about attempting a build than before.

With that said, I did have the following questions for those of you who have built 2203/2204 amps..

1. Is it better to just buy a kit, or source parts from various vendors as needed? My ultimate goal is a replica of a bone-stock JMP 2203, with the exception of an FX loop addition. Valvestorm seems to be the one w/the correct chassis for this (because of the extra holes on the back, and cutouts for rocker switches), so that's why I was thinking of going the multiple source route if I did do this...

2. Turret board vs PCB - for someone primarily used to PCB work, will using a PCB make for an easier transition into assembling an amp? If so, which PCBs are generally regarded as the best options? (Cannot remember the brand, but I do recall seeing one that was very neatly labeled and looked well made - almost "idiot proof", if you will).

3. Other tips and advice?

Would greatly appreciate some input!

Headfirst amplification in Australia has PCB boards…..and a good loop kit…..

 

[RoadShow]

I've delved deep into this having had one in the late 70s. My conclusion, get the Ceriatone British Style JCM800 2203 HW
https://ceriatone.com/british-style-jcm800-2203-hw/
And considering the cost difference is relatively minor, get it assembled. Plus there are nice features such as the ability to check and adjust biasing.
Look at the 2 dozen or so pictures they've posted of their amp.

Valvestorm is a great option, I built the Metro JTM45 through them, but to do it over again I'd go Ceriatone.

 

[Flight_of_Icarus]

I've delved deep into this having had one in the late 70s. My conclusion, get the Ceriatone British Style JCM800 2203 HW
https://ceriatone.com/british-style-jcm800-2203-hw/
And considering the cost difference is relatively minor, get it assembled. Plus there are nice features such as the ability to check and adjust biasing.
Look at the 2 dozen or so pictures they've posted of their amp.

Valvestorm is a great option, I built the Metro JTM45 through them, but to do it over again I'd go Ceriatone.

I've definitely considered Ceriatone before (and may do so again for possible future projects), but part of my interest in going DIY is for the experience and learning - that, and more selection process with parts.

Wasn't sure if they do custom chassis stuff either? AFAIK, they only offer the more common toggle switch cut chassis' and standard plexi face panels? I'm looking to stay more faithful to the late JMP aesthetics, so I'd need to go elsewhere for a head cabinet and need a chassis cut for the rocker switches.

 

[dtier]

Check out Modulus amps too for a rocker switch style chassis.

 

[Flight_of_Icarus]

Okay, I'm back with another question (and one which could be it's own thread - and perhaps a heated one at that!).

I've priced out the majority of the parts for a 2203 build if cherry picking parts (as opposed to a kit). What really caught me off guard however is transformer/choke prices - quite a dramatic difference between Mercury Magnetics and other options like Heyboer, ClassicTone, etc...less so for choke prices, but MM PTs or OTs seem to be more than double the cost of the alternatives...

So - is there something really special about the Mercury Magnetics stuff? Or is there just a lot of brand tax?

 

[Chris-in-LA]

My opinion? Mercury is fine but not worth the premium. My Heyboer/Valvestorm builds rival my stock 800’s.

 

[Purgasound]

Yeah you're good going with more inexpensive transformers. I've seen plenty of no-name transformers in some older JMP's I've worked on and they still sounded great. Mercury makes a good product but I don't believe the increased cost makes it sound any better. They have been accommodating whenever I've had questions about specs and they do have some hard to find transformers. I don't think anyone else keeps 200W ultralinear output transformers in stock but they have them. In cases like that I can understand the higher cost.

I like sourcing parts from different vendors. It's also cool that ST1 reproduction boards are now available. This saves a lot of build time rather as opposed to building an eyelet or turret board. Less work too since the traces are already laid out.

I've made up an ST1 layout diagram. I still need to complete the graphics for the output and power selector switches before it's released. There are so many hacked up JMP's and 800's out there my goal was to do period correct layout diagrams for certain years so people could easily identify mods and put their amps back stock if needed. There are a lot of small details that get missed in other layouts. For example a period correct 80's 800 MV circuit might have a hot shield on V1 and a late 70's JMP MV circuit would have a pink input wire globbed to the PCB with white caulk. I've also got another drawing in there that optimizes the shielding for both grids on V1 and implements other grounding schemes as well as elevating the heaters. A lot of it is overkill. Shielding the input wires makes a positive impact on preventing noise and unwanted interference. I've done elevated heaters and different grounding but it's honestly not really necessary. If the lead dress is good the amp will be quiet without it.