Yet another 124 build

[GAStan]

Hello forum!

I've been lurking here a while soaking up as much knowledge as possible. I love being in a room full of people much smarter than me (not that hard ), I keep hoping some will rub off on me.

I've been thinking about my next amp build for some time. Finally decided to try #124 and am now committed to see it through. I decided to make this post today, the day I actually firmly decided to do this. I wanted to provide a beginning to end thread with actual dates of significant events of this build.

So how far along am I? I have read things. A LOT of information is on this site alone. I feel I am ready to begin. So I ordered a set of boards and chassis from Erwin_ve. Very nice gentleman to do business with. I should have a tracking# tomorrow. So I have spent some money on this, to me that means I've committed myself to this project.

Next up is transformers. Found a lot of info here on them for #124. I've pretty much decided on Heyboer PT and OT from Mojotone. Not the most economical option but I believe they will work fine and the OT has 4 8 and 16 ohm taps. Still need a choke and power for relays.

Soon I will work up my BOM for all other parts and get them ordered.

Everyone please feel free to comment on this thread, I'm open to any suggestions or advice given.

Glenn

[GAStan]

Received an email from the Netherlands that I have a package on the way. Thank you Erwin for the prompt shipping!!!

[dbharris]

Looking forward to watching your build progress!

-Dan

[erwin_ve]

Received an email from the Netherlands that I have a package on the way. Thank you Erwin for the prompt shipping!!!

No problem, my pleasure!

[GAStan]

I've been looking at different transformer options. Current pricing I have found:
$325 shipped for Heyboer/Mojotone. Pricing on website.
$410 +shipping for Pacific Transformer. Quick response to inquiry.
Mercury Magnetics similar or more than Pacific, pricing on website.
Merren hasn't responded to pricing inquiry I submitted a few days ago.
Not considering Hammond so have not gone down that rabbit hole.

Prices for PT, OT and choke.

Now the Heyboer look even better to me.

Glenn

[erwin_ve]

Power for relays: hammond 186B12.Wire the secondaries for 12v, this will match with the relay rectifier/filter board I sent you.

[ChopSauce]

Hi Glenn,

Where are you from?

If you leave in Europe, I am curious at if the price for the trannies includes import taxes etc?

NB I'd recommend Erwin, too ...

[GAStan]

Hi Glenn,

Where are you from?

If you leave in Europe, I am curious at if the price for the trannies includes import taxes etc?

NB I'd recommend Erwin, too ...

I live in El Paso, Texas, USA. I'm afraid I have no idea of what the import taxes would be.

[GAStan]

Need a bit of help.

I've been looking through ODS builds but haven't found one that specifically uses Erwin's chassis and boards. Can anyone please point me in the right direction? I have been working on the BOM putting together shopping lists at some vendor sites and need a bit of information. Specifically which jacks are a direct fit for the holes for the pedal and which size switches are needed for the various controls such as PAB, Bright etc... as well as other general questions. I will hold off on actually ordering until I have received the chassis but it's nice to have the parts order as far along as possible.

Glenn

[erwin_ve]

This is a build with my boards, most of the boards are delivered in black these days.
https://ampgarage.com/forum/viewtopic.php?f=4&t=33037
Bluesmaster but you get the idea.

And this one: 2nd gen hybrid.https://ampgarage.com/forum/viewtopic.php?f=4&t=32822

[Reeltarded]

Heyboer, 100%.

I buy from AmpPartsDirect. APD part numbers on stock line vintage pattern parts. Priced sensibly.

[erwin_ve]

Old BOM for #124 and #183:

https://ampgarage.com/forum/viewtopic.php?f=4&t=30151

https://ampgarage.com/forum/viewtopic.p ... 80#p159980

[GAStan]

Thank you Erwin and Reel for your help!

Well....looks like I've had a change in plans. I didn't realize Erwin's boards aren't really fully suited to a 124 build when I purchased them. That's ALL on me, in no way Erwins doing. His filter board is more suited to something like a 183 build that utilizes 47uf x 2 in the B+2 to B+5 section rather than the 20uf and 10uf x 2 of 124. Not a big deal to me, I'm flexible. I didn't have my heart set on "it HAS to be 124". I basically just want a Dumble style amp and that is what I'm going to end up with. This is definitely an enjoyable learning experience.

Think I'll go with a 183 type power supply and 124 based pre and power amps. To start with. Something tells my I'll just HAVE to tweak it a bit, just because... Actually the 183 power supply won't be accurate, I'm having trouble finding 330uf/350v caps in stock anywhere but I have found some 220uf so I'll go with them. Not sure 300uf would fit the board anyways.

Now if I the delivery company would just get the chassis and boards here....

Glenn

[ijedouglas]

Thank you Erwin and Reel for your help!

Well....looks like I've had a change in plans. I didn't realize Erwin's boards aren't really fully suited to a 124 build when I purchased them. That's ALL on me, in no way Erwins doing. His filter board is more suited to something like a 183 build that utilizes 47uf x 2 in the B+2 to B+5 section rather than the 20uf and 10uf x 2 of 124. Not a big deal to me, I'm flexible. I didn't have my heart set on "it HAS to be 124". I basically just want a Dumble style amp and that is what I'm going to end up with. This is definitely an enjoyable learning experience.

Think I'll go with a 183 type power supply and 124 based pre and power amps. To start with. Something tells my I'll just HAVE to tweak it a bit, just because... Actually the 183 power supply won't be accurate, I'm having trouble finding 330uf/350v caps in stock anywhere but I have found some 220uf so I'll go with them. Not sure 300uf would fit the board anyways.

Now if I the delivery company would just get the chassis and boards here....

Glenn

Hey Glenn,

The precision power supply (183 style) is still very close to the 124 power supply and IMO can be interchanged. In essence you just have 8 x 47u caps in parallel to make 4 caps of 23.5uf Change your dropping string from 3K-22K-2.2K to 2.2K-22K-2.2K, 330uf reservoir caps to 300uf and you have the 124 power supply (220uf are fine). There is a slight difference with the grounding scheme (183 grounds screens and PI together whereas 124 grounds the PI with V!/V2 ground) but I think the difference is negligible.

[GAStan]

Hi Ian,

Yes I had picked up on the 2 x 47uf in series is 23.5. I was mostly just letting everyone know I'm not attempting a "purist" replica type of build. Actually I'm building this to ultimately go to my 14 year old son. He's already a pretty talented player, better than me (not saying much there lol).

The 2 x 47uf scheme makes better sense to me. I feel like this would increase the lifetime of these capacitors over running the single 20uf at near its rated max voltage like 124 does. It also adds to safety by bleeding off the capacitor charge via the balance resistors upon power down.

I had not dug deep enough to know about the different grounding schemes. Definitely something I'll look into and keep in mind while tweaking the sound. Thank you for pointing this out.

Glenn