Amp Build Help! BE-50 Transformers and Chassis questions.

jjjimi84

jjjimi84

Well-known member
The time has come for the little birdie to fly away from the kit nest and build a big boy amp. After building two Trinity amps kit, an Allen amp kit, two Metro amp kits and the latest SLO30 kit, I really have narrowed down what I want in an amp and decided the Friedman BE-50 would be an ideal amp for me. I love the idea of 50 watts and two channels with a JTM45 style clean and a heavier gain side, this started the search that lead to AA Electronics and the Black Eye 50.

www.aaelectronicspcb.com

Black-Eye hot-rod | AA Electronics PCB

This PCB can be used to build brown-sound hot-rod clones by using a single platform - no need to use separate boards for the relays - it will be all integrated. By purchasing this board, you get access to full schematics and layouts tailored for my boards. I've documented most Black Eyes models...
www.aaelectronicspcb.com www.aaelectronicspcb.com

Now armed with PCB, BOM, Schematic and Layout I have realized that I might be a bit over my head. I understand how to buy parts and populate pcbs and the basics of amp building but the part I am struggling with is finding the right transformers and chassis.

Let us start with the Transformers, the original uses a Heyboer HTS-12037, this is a power transformer with a 14v 2.5 amp accessory tap that powers the relays for the amp switching. I contacted Heyboer and they will not sell me one directly but did send links to this one;

shop.amppartsdirect.com

Marshall JMP 50W Plexi & JTM50 Style 50W Laydown Power Transformer Upgrade APD-8089-H

Heyboer TransformersPremium guitar amplifier power transformers, output transformers and chokes.Proudly manufactured in the U.S.A. Our Part# OEM Part# Type Rating APD-8089H HTS-7854-APD Power 50W 120/220/240V Laydown Alternates: None Reference#: 50W Power Transformer, Drake1202-118...
shop.amppartsdirect.com

This transformer meets all of the specs except the accessory tap is 5v at 3 amps, will this be enough to meet the requirements for relays?

If not, is there any transformer manufacturers that might make the set I need? I reached out to Andrea of AAelectronics and he has recommended inMADout for a set but they will not respond to any emails….

Once I nail down this little bit of transformer snafu, the next is the chassis. Do I grab a blank and try drilling it myself or order up all the parts and do a layout and have one manufactured?

So many questions, my dear friends, anybody up for some hand holding?
 
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I will attempt to help, although I am NOT a pro.

Looking quickly over the schematic, it looks like the accessory tap you mention powers the relay and V1, 2 and 3 heaters through a voltage regulator and rectifier. So you need a 14V - 2.5+amp for this. You can't use a 5V (you'd rectify the 14V down to 12.6). I don't see how the transformer recommended fits the bill in any way without some pretty tough changes on the components and wiring.
I would suggest to write down what you need from your power transformer and contact custom companies to get a quote. You might be surprised. My custom 1 off transformer for my DL clone came out just under 100€ and it was just as beefy.

As for the chassis, you can look into the Hammond off the shelf ones and drill yourself. It's not hard if you have access to a pillar drill. If you don't, more problematic but still doable. The only issue with the Hammond is that they are relatively thin so if you need for some reason to put the transformer somewhere in the middle you'll have some flex. There are companies that make custom chassis with and without holes for guitar amps and you can ask for what you need. Or do like me and order a one off from a company that does roofing, for them a guitar chassis is a gutter with a weird ratio ;)

What's your location? Maybe we can point you in the right direction?

Edit : not sure you are supposed to share those .pdf
 
I would contact Heyboer again and explain about the 5v vs 14v windings, they may not have caught this when they made their recommendation.

I have had good luck communicating with APD, maybe reach out to them to see if they do actually carry the correct one.

Finally, get with AA Electronics and explain the issue. Maybe they've came across this before and have a quick solution.

Welcome to the wonderful world of parts sourcing :eek:
 
Guardians of the analog said:
I would think that since the BE is a modded 800 style amp that using a mojo tone transformer set would be fine. Then from there using a mojo tone chassis and modifying it as needed.
Click to expand...
Mojotones transformers didn’t quite fit the bill, unfortunately.
Asdrael said:
I will attempt to help, although I am NOT a pro.

Looking quickly over the schematic, it looks like the accessory tap you mention powers the relay and V1, 2 and 3 heaters through a voltage regulator and rectifier. So you need a 14V - 2.5+amp for this. You can't use a 5V (you'd rectify the 14V down to 12.6). I don't see how the transformer recommended fits the bill in any way without some pretty tough changes on the components and wiring.
I would suggest to write down what you need from your power transformer and contact custom companies to get a quote. You might be surprised. My custom 1 off transformer for my DL clone came out just under 100€ and it was just as beefy.

As for the chassis, you can look into the Hammond off the shelf ones and drill yourself. It's not hard if you have access to a pillar drill. If you don't, more problematic but still doable. The only issue with the Hammond is that they are relatively thin so if you need for some reason to put the transformer somewhere in the middle you'll have some flex. There are companies that make custom chassis with and without holes for guitar amps and you can ask for what you need. Or do like me and order a one off from a company that does roofing, for them a guitar chassis is a gutter with a weird ratio ;)

What's your location? Maybe we can point you in the right direction?

Edit : not sure you are supposed to share those .pdf
Click to expand...
I am in Wisconsin and never thought about contacting a roofing company, good idea!

Any suggestion of transformer companies?

I figured I shouldn’t and will take them down…Going to upload just a snapshot of the needed parts. Thank you for looking, I appreciate it @Asdrael
GAStan said:
I would contact Heyboer again and explain about the 5v vs 14v windings, they may not have caught this when they made their recommendation.

I have had good luck communicating with APD, maybe reach out to them to see if they do actually carry the correct one.

Finally, get with AA Electronics and explain the issue. Maybe they've came across this before and have a quick solution.

Welcome to the wonderful world of parts sourcing :eek:
Click to expand...
Great idea @GAStan when I contacted Heyboer I asked for a specific model number, maybe they have something closer inline to what I need.

Going to reach out to APD and see what they recommend. I have reached out to AA Electronics and he pushed me to go through inMADout and they will not respond.
Harry Klippton said:
I think musical power supplies will wind to your specification
Click to expand...
Did not know they existed! Thank you! Digging into it now!

Any chassis maker recommendations?
 
I had a quick look at Hammond, their PT won't fit. You might find something somewhere off the shelf but a 100V bias tap is not that common, it's usually 50V, so you'd have to change the bias circuit. But really, a decent transformer company (any size!) can wire you something with 4 secondaries no problem. Get a couple of quote and see from there. I would have given you leads but I am in the EU so that wouldn't make sense for you, sorry.

As Harry mentioned, if you are really averse to drilling, you can 3D model a chassis and send it somewhere to fold/drill. I am fairly sure a Hammond chassis + a step drill bit would be significantly cheaper though, and those are even available through Mouser. As for the "gutter" trick, what you are looking for is a bent to order C-profile aluminum. I would recommend 2mm (I got 3mm and it was unecessarily difficult to work). The Hammond are 1mm and I personnaly find it too thin. My cut to size C-profile 3mm ended up exactly the same price as a 1mm Hammond of the same size...
 
My transformer rec would be get what's best overall for the core amp, disregard the relay requirements. The Heyboer stuff from APD is priced well, I've had good luck with them. Then for relays, and perhaps DC heaters for your preamp tubes as well, get one of these:


Mains AC in, anything from 85-264V AC , and 12V DC out.

Chassis, I am in the same boat. I bought a Hammond for my next build but I wanted bigger so I ordered a custom one from this company:

It's coming tomorrow. I'll post pics in the mailbox thread.
 
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