Converting Brain May Deacy amp to a Pedal?

[trebbooster]

Hello,
I was wondering if anyone would have any idea how to modify the Brain May Deacy amp into a pedal? The strip board diagram I'm looking at using was put up by Paul in the lab https://paulinthelab.blogspot.com/search?q=deacy
If anyone here would know how to possibly turn this into a great pedal, please post your mods.
Thank you and have a great week

[kaycee]

Not as easy as it might seem. The Deacy sound is an amp into a small speaker cab, so you'd need to build a cab sim to emulate the sound of a hi fi speaker.

[Kipper4]

It's been done. Digit did this.

Use the forum search. To find more info.
Plus IIRC this is a positive ground circuit so this will have to be taken into consideration when boxing.

Welcome aboard trebbooster

[digi2t]

Yeah, done it, but lots of the magic is in the speaker and enclosure.

I built mine using the bipolar power section out of the Schumann stuff. Power comes from a 12VAC wall wart. I integrated the Brian May treble booster section into it, so positive power to the booster, and negative power to the amp section. The only add-on was input caps to change the voicing of the booster, and loop jacks in case I wanted to use another booster on the front end. I boxed it as a pedal in a 1590DD, with a nice old 70's era Sony speaker cab as a plug in unit.



If you do decide to go for a speaker, go for the absolute cheapest, paper coned, full range speaker you can find. Generally, the cheaper, the better. I bought two, a 6" at $12, and an 8" at $4. The $4 8" won hands down. Between 5" and 8" will do, but at those prices, you can buy a couple and audition them.

As for using it as a pedal into another amp, you'll lose some of the Brian May feel. Like kaycee says, you need a cab sim, and even then, I don't know if it will capture the feel of a 6" paper cone speaker being pummeled by 1 watt of fury.

[Kipper4]

Yep that.

I have mine housed in an old stereo system speaker cab from the 60s.
5 or 6" speaker
Record out board.
Headphones out mod
Speaker out
Built in npn bc182 treble booster. Needs 2x power supply.
Patch cable treble booster to amp in. Leaves the option open to try other effects.
On its own it's a dark amp for my taste.

Brought the kit and did the add ons. With a lot of help.

[trebbooster]

WOW Thank you for all the responses!   Very kind of you to reply, and
digi2t, Thats your video? Wow Ive set thru that before. Really nice of you to share all your notes on this.
ok, heres one other off question, would it be a total overhaul of the circuit to make it a a positive power pedal / amp? 

[digi2t]

I suppose it would be possible to convert the amp to NPN. Reversing all the caps is the easy part, but finding suitable NPN germanium transistors might be tough. Russian GT404's might do the job, but I don't know if they meet the required criteria for this application. I think they're only rated to 500mW.

Then there's the mojo factor as well. Reversing polarity might be akin to "crossing the streams" where that's concerned.

[trebbooster]

I suppose it would be possible to convert the amp to NPN. Reversing all the caps is the easy part, but finding suitable NPN germanium transistors might be tough. Russian GT404's might do the job, but I don't know if they meet the required criteria for this application. I think they're only rated to 500mW.

Then there's the mojo factor as well. Reversing polarity might be akin to "crossing the streams" where that's concerned.

digi2t, since you have invoked the "crossing the streams" proviso, I officially withdraw my question LOL
thanks to everyone for all the info, it's appreciated .
treb.

[tablebeast]

Do you have the schematic for this and/or you offer a PCB for this project? Looks cool!

Yeah, done it, but lots of the magic is in the speaker and enclosure.

I built mine using the bipolar power section out of the Schumann stuff. Power comes from a 12VAC wall wart. I integrated the Brian May treble booster section into it, so positive power to the booster, and negative power to the amp section. The only add-on was input caps to change the voicing of the booster, and loop jacks in case I wanted to use another booster on the front end. I boxed it as a pedal in a 1590DD, with a nice old 70's era Sony speaker cab as a plug in unit.



If you do decide to go for a speaker, go for the absolute cheapest, paper coned, full range speaker you can find. Generally, the cheaper, the better. I bought two, a 6" at $12, and an 8" at $4. The $4 8" won hands down. Between 5" and 8" will do, but at those prices, you can buy a couple and audition them.

As for using it as a pedal into another amp, you'll lose some of the Brian May feel. Like kaycee says, you need a cab sim, and even then, I don't know if it will capture the feel of a 6" paper cone speaker being pummeled by 1 watt of fury.

[digi2t]

Do you have the schematic for this and/or you offer a PCB for this project? Looks cool!

I used most of this for the amp section;



The boost is based on this, and I added an input cap selector that selects between the original 4n7, and three higher values;



For power, I used 12VAC, and split it through LM337/LM338 regulators for negative power to the amp, and positive power to the boost. There's a ton of schematic for this, I just borrowed what was in the Schumann pedals.

Sorry, no PCB....yet. Maybe one day.