Marshall Clone

[BluezyBruce]

Ok, I am wondering if anyone has been building marshall clones?

I am wondering about JCM 800, 2203,2204 amp in general early amps with a master volume. I am thinking the 50 watt over 100 but would love a 25 watt switch, different subject.

What I would like is a hand built amp with good components and trany's. I don't want to pay 2 grand for one, but still want good parts and a great amp when its all done.
This amp would be made for playing high gain but still be usable for clean also.

Let me know what you think and Info if you have please.

Thanks, Bruce

 

[Ben Harmless]

I've been playing out of my home-built 2204 for about four years now - and tweaking it the whole time. I do genuinely love the circuit, and I'd recommend it to others. I find that I can get clens that I'm very happy with by rolling back my guitar's volume, though they're not Fender cleans by any stretch.

I know the good Mr. Crash has build a 2204 and a variant or two, and will probably chime in. I'm happy to answer any questions I can based on my experiences.

The one thing I'd recommend before you begin is to look at an output transformer from someone other than hammond. I'm becoming more and more covinced that my OT is responsible for some of the issues with spikey harsh highs that I've been battling since I first fired it up. I get compliments on my tone all the time, but I'm never satisfied...

 

[Wally]

IF I were going to clone a 2203/2204 Marshall, I would look at the original JMP's from the '70's.The earliest JCM 800 models of these amps were more or less identical to the JMP's, but the later JCM 800 2203/2204 amps with the horizontal inputs had some changes that take the amp away from the classic Marshall tones. Also, if you want true HIGH gain, these amps don't quite go there.

 

[BluezyBruce]

I am hoping to go with Heyboer trany's if I can, other than that mercury magnetics.

I do appriciate all the help I can get. Other than a schematic (I think) that is all I have so far.

I was planning to use Sozo cap and corbon resistor throughtout except throught the power section. Suggestions on part would be great also, So chime in and let me know.

Thanks Bruce

 

[JohnnyCrash]

I've built quite a few 2203 based amps. Some around 5 watts (AX84.com type single enders), some around 20 watts (using 6V6s or EL84s), and others around 50 watts.

I have two suggestions:

If you really want that JCM800 type sound, go ahead and build one. They are my favorite amps.

If you want a "classic" Marshall type sound, that gets plenty crunchy without blowing out the windows - build a slightly modified plexi 50 with a PPIMV control.

--

I usually tweak my output caps to larger, Superbass type values either way - adds a bottom end most JCM800s can't pull off and gives the plexi even more body. Sometimes I tweak the tonestack or add some relays for two channels, but otherwise they sound great stock.

As for the plexi - it is my favorite amp to record with. Plenty of crunch. I tweaked it for a tad more gain (bypassed the tonestack's cathode, if I remember correctly). The PPIMV though, allows you to crank the stock plexi preamp, without having a Woodstock, ear-bleeding reaction

It has plenty of crunch for rock/punk/etc, but it can't do the extreme gain thing of a JCM800 (punk/metal/industrial/etc).

--

The ugly orange one is my plexi 50 (Mojo had a custom order for the cab that fell through, so I saved a few bucks). The one on the bottom with the crooked/misapplied Marshall logo is a JCM800 2203 circuit I added another preamp tube and channel with a MV/Gain control for each, as well as 12v relays for footswitch channel selection:

This is my latest JCM800, it's a 2x10" combo with as deep of a bass as my closed back 2x12"!! It has an adjustable footswitchable "solo volume boost" (a 250k pot between the MV and ground) I used 5v relays powered by the tube heater supply for the switch/relays - I built the cab out of birch ply, gave it a deep angle for sound dispersion, and put on a '77 Cadillac chevron/wing for good measure:

 

[Ben Harmless]

Take a look at ceriatone for some good layouts. I'd be happy to email all the documentation I've gathered if you're interested. Mark Huss at mhuss.com has drawn out the clearest schematic I've come across.

For what it's worth, the 50 watt master volume, JMPs that define the 50 Marshall MV tone, are idential to the 50 watt JCM800s in terms of circuitry - at least by the schematic. The 100 watt amps reduced filtering over time, but the 50s staye consistant. One thing that did change however is that later models had increased B+ voltages. Mine, with a Hammond PT measures fairly high. My '82 JCM800 measures much lower. I think this is also partially responsible for the brighter overall nature of my homebrew amp.

Don't skimp on the shielded grid wires on the first couple of gain stages. Other than that, it's a reasonably forgiving circuit to get up and running. Have a blast!

 

[Wally]

Ben, compare the schematic of a JMP 2204 to a JMP 2203....and then look for a schematic for the later JCM 800 Series Md. 2204 from the 80's....maybe '83 on. I know the 1988 schematic for the 2204 shows a different preamp from the original JMP 2204. Marshall was by then using the same preamp for the 2204 as they used in the 2203.
IN fact, the JMP 2204 looks very similar to the JMP Md. 1987 non-MV 50 watt Marhall except for the addition of a pre-phase inverter MV. The 100-watt Md. 2203 has little resemblance to the 100-watt Md. 1959 Super Lead non-MV. the 1970 schematic for the Md. 1959 has more in common with the Md. 1987 and the MD. 2204, in fact, in the preamp, than it does tihte the MV Md. 2203 100-watter.

 

[Badside]

The one thing I'd recommend before you begin is to look at an output transformer from someone other than hammond. I'm becoming more and more covinced that my OT is responsible for some of the issues with spikey harsh highs that I've been battling since I first fired it up. I get compliments on my tone all the time, but I'm never satisfied...

If I may ask, are you using the "replacement" OT (1750N I think) or one of their universale series (1650something).

I'm asking because my 50W clone has the 1750N and I really have no problem with spikey harsh highs.
I must say, the tone warmed up after I switched to a 2X12 (vs a 4X12), speakers seem to work better when they're working harder.

Mine has the 2204 architecture, but with 1987 (50W Plexi) voicing, which means the 2nd gain stage is a warm 820R/22u instead of the cold 10k of a 2204, and the the CF driver is bypassed. I've also lowered the first coupling cap (before the gain control) to 0.01u for a tighter sound.
Used to have a resonance control but I prefer the tighter sound of a full bandwidth NFB loop.

I personally think a 50W Marshall is not much more difficult to build than say a 5E3, if you follow a proven layout and pay attention. It mostly takes more time.

 

[rsi106]

I just built a JCM800 2204. Parts, not including head box, were $469.93. This was not a kit. I bought the parts from whoever had what I wanted.

If you want something for lower power build it with a PPIMV like johnnycrash said. Or, add a mosfet type circuit like a VVR controlling the B+/bias.

As far as the differences between a 1987 and a 2204, etc., once the thing is built you can go to town swapping out cathode resistors/caps, bypass caps, slope resistors, NFB stuff, etc. until you get something you want to keep.

 

[Ben Harmless]

Someday I'm going to learn to be a little more specific.

Ben, compare the schematic of a JMP 2204 to a JMP 2203....and then look for a schematic for the later JCM 800 Series Md. 2204 from the 80's....maybe '83 on. I know the 1988 schematic for the 2204 shows a different preamp from the original JMP 2204. Marshall was by then using the same preamp for the 2204 as they used in the 2203.
IN fact, the JMP 2204 looks very similar to the JMP Md. 1987 non-MV 50 watt Marhall except for the addition of a pre-phase inverter MV. The 100-watt Md. 2203 has little resemblance to the 100-watt Md. 1959 Super Lead non-MV. the 1970 schematic for the Md. 1959 has more in common with the Md. 1987 and the MD. 2204, in fact, in the preamp, than it does tihte the MV Md. 2203 100-watter.

Wally, you're absolutely 100% right on the solid facts. The earliest 2204 circuit was exactly as you describe - essentially a watered-down plexi with a pre-PI master. I've only ever heard this amp described as "weak." It lasted only a very short time (signs point to just into '77) before the 2204 preamp was changed to the same circuit as the 2203. I see some places like Dr. Tube (otherwise a fantastic source) erroneously say "this amp was in production from 1975 to 1981" but this is only true if you say that the 2204 was in production for that time. I believe as early as '77, there were cascaded MV 2204s on the market. Most of the JMP MV amps that exist were built this way - I would have mentioned the exception, but I was on my phone, and yeah, I was lazy. One thing's for sure, they made the transition long before the 800 2204s came about.

If I may ask, are you using the "replacement" OT (1750N I think) or one of their universale series (1650something).

I'm asking because my 50W clone has the 1750N and I really have no problem with spikey harsh highs.
I must say, the tone warmed up after I switched to a 2X12 (vs a 4X12), speakers seem to work better when they're working harder.

Again, I should organize my thoughts more clearly before I post. I did use the 1750 series trannys - but I used a 100w transformer and adjusted my outputs accordingly to maintain the proper impedance, as well as tweaking the NFB. I was looking for a little more beef to the amp, but I think I surrendered a good amount of the positive aspects of transformer saturation, and this may be part of the issue. Whatever the case, I've got the thing voiced pretty close to perfect now, and I prefer the overall tone to my genuine '800 - though that amp still makes it onto recordings.

I'd still tend toward using a different OT, from a smaller manufacturer at this point. Hammond makes a ton of the 2204 transformers and they've been doing so for a lot longer than some of the smaller newcomers, with little or no reason to improve the design. I'd say those newcomers have every incentive to improve over what Hammond's got to offer. I'd probably look at the Magnetic Components ClassicTone series at this point. I'd also steer away from Mercury, just because I resent the overhype, and because of this absurdity.

 

[Bohdan]

Mod an old Traynor...

 

[big-daddy-59]

Hey Ben, do you really think that $10 for a 14AWG power cord is absurd? Yes granted, they are making some dubious claims but really, they aren't any worse than some of the "audiophile" power cords that they sell for stereo gear. And those tend to sell for ridiculous prices. $10 for that market would be a steal.

 

[Ben Harmless]

Hey Ben, do you really think that $10 for a 14AWG power cord is absurd? Yes granted, they are making some dubious claims but really, they aren't any worse than some of the "audiophile" power cords that they sell for stereo gear. And those tend to sell for ridiculous prices. $10 for that market would be a steal.

It's not the price at all - it's the claims. They're absurd when the audiophiles make those claims, and they're the same when Mercury makes them.

Your power is only going to be as "good" as the weakest link in the chain, and 94 times out of 100, that link isn't the copper going from the wall to the amp.

Referring to a power cord as a "fix" - as if there's something broken? Every claim they make is dubious, and based only on the difference between 16AWG and 14AWG conductors. I've made enough of my living with my ears to know that there are always enough other factors affecting one's tone on a given day to suggest that this cord is the closest thing to snake oil. Hell, drinking water to affect your own personal hydration is free, and will probably have more of an impact that a bright red cable.

People get very convinced that their expenditures make a difference, and that any perceived difference (whether real or imagined) is "good." Whatever helps them sleep at night, I guess.

Yeah, I'd be way more irritated if it were $50, but I don't know why Mercury needs to engage in their circus-barker marketing rather than just saying "hey, our cord is way beefier, and may solve some problems for you at some point at the same price as other cords - plus, it's red, so you'll probably never get it confused with someone else's."

 

[Badside]

I'd still tend toward using a different OT, from a smaller manufacturer at this point. Hammond makes a ton of the 2204 transformers and they've been doing so for a lot longer than some of the smaller newcomers, with little or no reason to improve the design. I'd say those newcomers have every incentive to improve over what Hammond's got to offer. I'd probably look at the Magnetic Components ClassicTone series at this point. I'd also steer away from Mercury, just because I resent the overhype, and because of this absurdity.

From what I remember, the 1750 series has only been around for 5-6 years. The company has always been popular with DIYers because of their extensive "generic" transformers selection.

That said, I've been wanting to give the ClassicTone a try for a while now, but I keep getting back to Hammond cause they're so cheap and plentiful (I live in Canada). I can buy them at my local electronic surplus store, they stock the full 292/1750 line!

I'm with you on the Mercury Magnetics! It's unbelievable how many people install their stuff on china-made transistor filled modern amps hoping to turn them into vintage jewels.
That said, just like with Sozo, it's one of the rare companies that cater to the needs of us weirdo solder junkies. It's part snake oil, part flamboyant marketing, but they offer much more options than other companies that offer these products only as an afterthought (like those Sprague caps that hide smaller caps in them).
To Magnetic Components (ClassicTone) and Hammond, the guitar line is really a small portion of their income. God bless them for recognizing us

 

[BluezyBruce]

I have to admit I have not played many marshall amps, owned a few but play a few minutes on a 1987x modded with the Voodoo labs high gain jose mod and I liked it and think it was usable but could get to bright and icy.

I have to ask are the same differences between a hand made marshall clone as are with a Fender? If so I think a 1987 quality build could be the ticket, But I would also like some additional gain, so how are the options of adding extra gain? I am not a channel jumper either so there should be the option of more gain available without adding tubes.

Let me know,

Bruce

 

[rsi106]

Regarding methods of increasing gain in a 1987 circuit, you should do some searches at the metroamp forum. You'll probably find about 700 thousand threads on that topic.

 

[JohnnyCrash]

I've used Hammond OT on several 2203/2204 style builds. No harsh highs. A lot has to do with speakers, guitar/pickups, personal taste, etc.

Ben, if you hear a difference between your old JCM800 and your DIY - you've already mentioned the difference in voltages - there may also be slight differences in the actual internals (bright caps, bypass caps, resistors, etc) - Marshalls are notorious for subbing slightly different values from production to production, so never completely trust a schematic to tell you want's reall inside.

Don't assume the brightness/difference is only due to the OT... the Hammonds have been great (not too bright) for me.

 

[Badside]

I have to admit I have not played many marshall amps, owned a few but play a few minutes on a 1987x modded with the Voodoo labs high gain jose mod and I liked it and think it was usable but could get to bright and icy.

I have to ask are the same differences between a hand made marshall clone as are with a Fender? If so I think a 1987 quality build could be the ticket, But I would also like some additional gain, so how are the options of adding extra gain? I am not a channel jumper either so there should be the option of more gain available without adding tubes.

What's wrong with channel jumping? It's really neat cause you can blend various amount of each channel to tweak your tone (the normal channel is too muddy on its own, and the treble channel too peaky, imho).

If you're not into channel jumping and want more gain, then the answer is to cascade your channels and add a MV, ala 2204 circuit.

Mine is basically a 2204 but with 1987 values, makes for a warmer and surprisingly gainier "JCM800" tone.
The Hi/Lo input scheme of the 2203/2204 allow you to bypass the extra gain stage, others have it on a switch.
Mine has a switch that basically goes from parallel (jumpered 1987) to cascaded (2204)... it's always on the cascaded mode.

 

[BluezyBruce]

I have nothing against jumping channels, I have never found it usefull to me is all, It may be different on a marshall. I like the idea of cascading with a MV.

I have not looked at the schematics but sounds like the 2204 with a 1987 circuit and a MV may be the track to go down with my little expierence of Marshalls.

All info on Cascading please.

 

[jefrs]

You can tweak the gain in the pre wherever you want it - without adding extra bottles.
Take a read of Merlin Blencowe "Designing Tube Preamps for Guitar and Bass" ISBN 978-0-9561545-0-7