Overhauling a 2010 Marshall 1987X RI - New OT, PT and Board

[clusterstudios]

Hello all, Happy day!! A very cheap 2010 Marshall 1987X w/ effects loop just fell onto my lap The thing is like new but the sad thing is that board and those stock transformers have to go. I've build a couple of Marshalls from the ground up using Metro kits in the past, so I know how to solder, but this reissue is different in that;

1) It's got an effects loop attached, so I need to figure out how to unattached/reattach it to the new board. Also,
2) The board has 6 stand-off bolts that doesn't accommodate the classic vintage board that Ray built for me, so I'm not sure if I need to drill a couple extra bolts or somehow work with what I got. Any ideas here??
3) The easy part is I have a MM OT Axiom 050JM-M and a Heyboer PT Model: HTS-8366 (9960545)

If anyone can point me to a tread or tell me the best way to do this I would greatly appreciate it. Is that stock effects loop any good? I could always just disconnect it... I looked at the Metroamp Zero lose loop I don't think it will fit in the existing holes.

Thanks again!!

[Thiez]

Whats the plan with the amp? Build in a superlead? Cause if thats the plan you can put the FXloop in the same place as it is now.

[clusterstudios]

Yes, I want to keep it as a 1997x. Not sure how to work the vintage style board in place of the modern one.

[neikeel]

Pretty easy to do.

Offer your board up to the chassis, pick at least 4 of the holes that line up and use those.
Metro used to offer boards with correct RI spacing - does valve storm now?

Next wire up your board as stock and decide if you are keeping the loop, if so you will need an Arcol to replace the large dropping resistor and chassis mount it, the rest is straightforwards.

[clusterstudios]

Thanks so much. Not sure about the effects loop yet. Anybody have a schematic for the 1987X w/ the effects loop?? Raymond Domzalski built my unpopulated board a while back and it's vintage correct, meaning that it won't accommodate all the standoffs in the reissue. Anyone know where I can get an Arcol ?? Thanks!!

[Thiez]

Pretty easy to do.
if so you will need an Arcol to replace the large dropping resistor and chassis mount it, the rest is straightforwards.

I don't understand this part. Can you explain it? Why you need a large dropping resistor when keeping the fxloop?
For the powersupply of the loop you mean?



Here is the schematic of the 1987 reissue with the fxloop in it. http://rudn.nodevice.com/preview/big/365/365997-1.jpg" onclick="window.open(this.href);return false;
Use the vintage schematic to build op your 1987 to vintage specs and use this scheme to put the fxloop in correct place.
The reissue has some other values from the vintage 1987 superlead.

[SDM]

Pretty easy to do.
if so you will need an Arcol to replace the large dropping resistor and chassis mount it, the rest is straightforwards.

I don't understand this part. Can you explain it? Why you need a large dropping resistor when keeping the fxloop?
For the powersupply of the loop you mean?

Yeah for the loop power. In that schematic, look for the 10 watt 47K resistor there (R33 lower left side), that's the resistor he's talking about. It provides the B+ to the stock loop board which needs a lot of voltage drop (and dissipates a good amount of power/heat) to get down from near full B+ to only 30V.

With a nice vintage looking board, would be a sore sight to see a large ceramic mounted on it somewhere like the RI board has, a chassis mount resistor means you can mount it in a more aesthetically pleasing way, dissipate the heat better, hence the Arcol recommendation (which you can get from Mouser, Digikey, Newark, etc... perhaps find locally if you've got a good electronics shop around).

None of this is needed if the stock loop is not going to stay, but will be if it is going back in. The ZL loop will not fit the the stock RI loop holes in stock form.

[neikeel]

Pretty easy to do.
if so you will need an Arcol to replace the large dropping resistor and chassis mount it, the rest is straightforwards.

I don't understand this part. Can you explain it? Why you need a large dropping resistor when keeping the fxloop?
For the powersupply of the loop you mean?

Yeah for the loop power. In that schematic, look for the 10 watt 47K resistor there (R33 lower left side), that's the resistor he's talking about. It provides the B+ to the stock loop board which needs a lot of voltage drop (and dissipates a good amount of power/heat) to get down from near full B+ to only 30V.

None of this is needed if the stock loop is not going to stay, but will be if it is going back in. The ZL loop will not fit the the stock RI loop holes in stock form.

Yes I have done it with an Arcol under the board - very discrete.

it is a shame but the RI loop has very close centres whereas Steve's ZL loop has the same hole centres as the output jacks (fits on a 4 output jack SL beautifully) only way to use Steve's loop is wiring it to chassis jacks with the board mounted away.

[Thiez]

Also depends on what transformers you gonna use. I used a IG transformer in my marshall build and that also had a 25VAC tap. When you put that to DC you should get around 30v for the FX loop without the need of a large dropping resistor. But you need a rectifier and capacitor again. So always extra parts..