[Spencerleehorton]

Hi All,

I'm in need of a hot rodded marshall type 50 watt amp and wanted to share my prep and build.
I'm not exactly sure if the ceriatone AH deluxe 50watt schematic is entirely correct to the original BE but it sounds damn good.
Having twin master and 3 channels is what I'm aiming for.
Want to build the turret board first and need dims for the FR4 size, have approximated it to be about 100mm x 480mm?
Any info or help would be appreciated.

[Spencerleehorton]

One of my first questions would be what relays to use?

Attached is the schematic.

I've updated the schematic as I'd posted the wrong one!!

[Spencerleehorton]

12v relays I can see on further inspection, but didnt know if it has to be specific because of the coil?

[Spencerleehorton]

Making a BOM at the moment and sourcing the components.
Just radio.com it seems I can get all the caps from, about £100 for them all.
The transformers and choke seem about £100 for the mains and output transformers each and £30 for the choke.
The chassis is about £50 and head cabinet from modulus is £265.
Gonna look for the pots and other bits, hopefully about another £150 for them.
So working out about £700 ish all in.
Much rather that than £4k for the original or £1500 + customs charge for ceriatone.

[Heikki]

Couple of things that stick out from looking at that Ceriatone layout. The wiring for switches "Thick", "Era" and "M69" might be a good way to turn the amp into an oscillator, so be ready for that. The way the rectifier and power supply reservoir cap are wired isn't ideal either. Same goes for the bias supply. Rest of the grounding won't probably matter much if just the rectifier and reservoir cap are done properly. If you plan to use that Ceriatone effects loop it most likely sucks. Most of these kit company effects loops are crap. I can send you a plan for effects loop that doesn't suck if you want. I wouldn't bother with DC heaters for the first 3 tubes. AC heaters are rarely a problem even in high gain guitar amps.

[Spencerleehorton]

Yes, please bud, if you can send any bits that will help to my email please:

[email protected]

would very much appreciate it, I dont quite understand on how to correctly wire the Thick/Era switches so to not get oscillation, if your able to explain with a diagram maybe?

you also mentioned doing the rectifier and reservoir cap properly? could you explain this as well please?

I was thinking about getting a zero loss fx loop kit, but i would welcome a better design any day, please send through.

regards

Spence.

[Spencerleehorton]

I've updated the schematic to the one I've been using!! As I posted an older one, not much has changed apart from some cap values.

[Heikki]

As long as the switches are in the back panel like in that layout picture there probably won't be any problems. I've seen some attempts to put switches like that in the front panel with long leads going crisscross the circuit board and the results were not good.

I'm not a fan of that random grounding scheme that seems to be going on in that layout, but it often works well enough in guitar amps. I would at least take the negative side of the rectifier directly to the - of the reservoir cap (see attachment). Same can be done for the bias supply, but it most likely wont matter because there are no big ripple currents flowing there.

Here's a schematic to an amp that is similar to what you're planning to build, but it has a decent effects loop.
http://tube.ghr.fi/frieddan/frieddan.sch.svg

I'll send you tonight when I get home gerber files for a pcb for that effects loop. The loop uses four BC547C transistors or any similar transistors can be used. The board has everything needed for an effects loop on it except you need to add a switch or a relay to switch the loop in and out.

[peterc]

Hi Spence

The Zero Loos loop schem was published here on GDIY awhile ago, but I cant find it right now.
Uses a pair of LND150 AFAIR
Heikki's also looks good....

[Spencerleehorton]

is the zero loop ok? Im sure i can find it and trace it as long as its single layer pcb.

[peterc]

From what I have read on the amp forums, it seems to be very transparent.
Never used it myself.....

[Spencerleehorton]

I'm waiting for parts for the turret board and making the fx loop

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