Marchand PM224 R1218

Well I thought I'd show some progress on one of my amps in Progres. In about 2019 I had contacted Phil Marchand for a PM224 kit. Phil told me he really didn't sell diy amp modules kits any more but I implored him, and he relented, putting together a

PM224 R1218

kit for me. I told him to take his time in putting the kit together and it was Christmas so I wasn't in a big hurry. Some time later I received my kit. To be honest I had never seen this version of the PM224. It seemed to me the VAS stage was different and there was no facility to separate the power feeds between the output and front stage. I went about building the amp module and tested it and all was awesome! I put it on a shelf and went about collecting and making the different parts for the amp.
There is a diyaudio Soft Start and Speaker Protection kit, as well I created a custom, multi-capacitor bank (akin to the old adage that many are always superior to the equivalent of the one). I always wanted to try a CRC based filter and I'd been exposed to a lot of different PS configurations in my job as a cnc/electronic technologist and decided to try a combination of CRLC. I've used CLC filters and I thought maybe there was a best of both worlds here.

well most my parts collection was completed about 2 years ago but I fell ill and all went on a back bench. I've been poking away at it lately and my god I'm actually getting somewhere. I got at least 60 taps completed in each of the heatsinks and parts positioning has been worked out other then one small transformer. It's taken quite some time and I've had help manipulating the larger/heavier parts. the transformer is a 25-0-25 500va Antek and I incorporated some parts from a CA-150.

I created custom 2mm copper heatspreader/anglebracket for them and I've had a bunch of these massive heatsinks I bought off a dude on the east coast many years ago (that was a MASSIVE shipping bill). I think each weighs about 20 lbs!!! and the trans weighs a ton also. I'm gonna have a friend put this on a small wheeled stand for me so I can move it around easier.

enjoy the photos and I should have this complete soon, it will remain my focus till this happens (I have too many projects going here, I gotta finish some!)
 

Attachments

  • File_000.jpeg
    File_000.jpeg
    456.4 KB · Views: 77
  • IMG_2492.JPG
    IMG_2492.JPG
    434.7 KB · Views: 76
  • IMG_2491.JPG
    IMG_2491.JPG
    393.1 KB · Views: 74
  • IMG_2490.JPG
    IMG_2490.JPG
    447 KB · Views: 77
  • IMG_2489.JPG
    IMG_2489.JPG
    472.2 KB · Views: 74
  • IMG_2488.JPG
    IMG_2488.JPG
    410 KB · Views: 65
  • IMG_2487.JPG
    IMG_2487.JPG
    352.3 KB · Views: 65
  • IMG_2486.JPG
    IMG_2486.JPG
    489.5 KB · Views: 61
  • IMG_2486 - Copy.JPG
    IMG_2486 - Copy.JPG
    489.5 KB · Views: 76
and this is some back panel work, balanced in level control with switching for single ended option to be wired. and I will be adding the switching to bypass the balanced in level control. that switch cost me a pretty penny, 4pole/double throw switches aren't cheap!
 

Attachments

  • IMG_2496.JPG
    IMG_2496.JPG
    312.4 KB · Views: 28
  • IMG_2495.JPG
    IMG_2495.JPG
    358.5 KB · Views: 23
  • IMG_2494.JPG
    IMG_2494.JPG
    403.7 KB · Views: 30
  • IMG_2493.JPG
    IMG_2493.JPG
    412.5 KB · Views: 22
Last edited:
well, today I was able to find a spot for that small transformer. why is it always that you have to move this to accommodate that? just seems to happen every time. I also mounted the switch to short the balanced in pots. capacitors are mounted for the main part and the bottom is affixed to one side. always so much to consider. I think I've designed a pretty cool wiring layout for it. It should look neat, kinda got the idea from a tube amp I designed and built over 1996-1997 Edmonton awful winter weather, that was a seriously cold year there.

you know I thought I'd explain why I choose to go all out on a PM224. It was Marchands kits that really started me in the direction of building real high-end audio at home in the early 90's. I started with a W8 and then some active crossovers. I built a beautifully sounding amp out of a PM124 kit that was highly modified. 10 watts in class A and ran so hot you could fry eggs on it! I'd always wanted to build a PM224 kit with separate regulated supply for the front end. By the time I got to really committing Marchand didn't sell the kit anymore. So I begged Phil to put a special one together for me and I said take as much time as you need. I took about 2 months in total to get the kit. I built the amp module about 5 years ago and got it running really good but there was just so much I wanted to incorporate the execute on this bad boy. I just needed a serious kick in the *** to just put together all this darn work I did so long ago

anyways here's some more photos... enjoy
 

Attachments

  • IMG_2503.JPG
    IMG_2503.JPG
    455.8 KB · Views: 19
  • IMG_2502.JPG
    IMG_2502.JPG
    498.2 KB · Views: 16
  • IMG_2501.JPG
    IMG_2501.JPG
    409.5 KB · Views: 15
  • IMG_2500.JPG
    IMG_2500.JPG
    327 KB · Views: 12
  • IMG_2499.JPG
    IMG_2499.JPG
    336.3 KB · Views: 15
  • 73359914504__A24766EF-C9D7-4B28-B154-DDAAB8D4CF44.JPG
    73359914504__A24766EF-C9D7-4B28-B154-DDAAB8D4CF44.JPG
    453.9 KB · Views: 18
What I like about Marchand Amplifiers: by Shawnra
1. Marchand amplifiers are nice and work good.
2.They can be operated in Class AB or as deep into class A as your design is capable of handling.
3. They are very stable and hold bias and offset positions in place for extremely long periods
4. Phil Marchand is a pretty cool guy and I think one of the true pioneers for DIY mosfet based kits.

I got some more work done, that darn case is starting to get pretty crowded. Yeah I know some are thinking that back is never gonna fit back on. Well believe me it does, it is a seriously tight clearance but it does and that's what counts. Ran some nice ferrite beads on the secondary ac feed. routed +V and -V. Tomorrow, once the back is on, I'll route the star grounding configuration. Wait for it cause I think it's gonna look pretty cool :)

I also incorporated my RL filter board. There's a 0.05mH@10amp choke on the feed to the capacitors on the bottom and 4X0.47ohm parallel resistors for each rail.

Just an Idea I wanted to try out, I'll be curious to see how it affects ac output ripple and other aspects.

some photos, enjoy
 

Attachments

  • IMG_2505.JPG
    IMG_2505.JPG
    393.1 KB · Views: 22
  • IMG_2507.JPG
    IMG_2507.JPG
    485.9 KB · Views: 22
  • IMG_2508.JPG
    IMG_2508.JPG
    459.8 KB · Views: 23
Okay, so I've gotten a bit further along. It has taken me several days but I wired the input. There is a switch for single ended or balanced and a switch to bypass input volume pot if needed. The single ended balanced mode works whether pot is in or out of the circuit.
Put up a aluminum wall between main transformer and input wiring. I can now put the back on and start on the connecting up of the rest of the parts. Then onto grounding, which is a whole other topic.

some photos
 

Attachments

  • 73409285069__37B2C56E-0A4F-4C9C-B2AA-088C984D6897.JPG
    73409285069__37B2C56E-0A4F-4C9C-B2AA-088C984D6897.JPG
    456.1 KB · Views: 19
  • IMG_2513.JPG
    IMG_2513.JPG
    383.5 KB · Views: 13
  • IMG_2514.JPG
    IMG_2514.JPG
    471.1 KB · Views: 13
  • IMG_2515.JPG
    IMG_2515.JPG
    445.2 KB · Views: 13
  • IMG_2516.JPG
    IMG_2516.JPG
    430.8 KB · Views: 15
  • IMG_2518.JPG
    IMG_2518.JPG
    411.7 KB · Views: 14
so I have another update, very close to powering up the power supply and I'll let it run for a day. just to reform any old caps and stuff. None of the caps are more then 7 years old so I imagine most are still good. the back is on I'll complete wiring this evening and power up. It's starting to look like an amplifier. It is quite heavy so I've required a lot of help but hey the end is near!
I included the parts list. I don't have a schematic, Phil wouldn't share it with me but I don't think it's too different then the last version. I've never had an amp based around FQP type output mosfets but I've heard really good reviews.
 

Attachments

  • IMG_2522.JPG
    IMG_2522.JPG
    405.1 KB · Views: 13
  • IMG_2521.JPG
    IMG_2521.JPG
    467.4 KB · Views: 12
  • IMG_2518.JPG
    IMG_2518.JPG
    411.7 KB · Views: 12
  • IMG_2517.JPG
    IMG_2517.JPG
    518.4 KB · Views: 13
  • 73428375536__A7DB4307-FF95-4BEA-8FC3-E457E02EAEAB.JPG
    73428375536__A7DB4307-FF95-4BEA-8FC3-E457E02EAEAB.JPG
    445.3 KB · Views: 14
when you look at the amp from the side, you really start to get a feeling for the scale of this amp. It is one big, bad, boy!

I'm gonna guess it weighs 70 to 80 lbs. It was not my intention to make it so big. just a result of the parts I have on hand.
 

Attachments

  • IMG_2523.JPG
    IMG_2523.JPG
    516.5 KB · Views: 9
  • IMG_2524.JPG
    IMG_2524.JPG
    496.4 KB · Views: 10
  • IMG_2525.JPG
    IMG_2525.JPG
    397.9 KB · Views: 8
  • IMG_2526.JPG
    IMG_2526.JPG
    493.5 KB · Views: 10
Okay, so I got the power rails up today and they are just gonna run without the amps connected for about 24 hours. Just to let everything settle in the power supply.
I gotta admit it is one mean looking amplifier. I think it has a bit of a menacing look to it?

The rails are closely matched and... who'd of thought it but that el cheapo toroidal is absolutely whisper quiet. I am impressed!

I also wanted to mention the the input circuitry is star grounded to itself, the input will join ground at the input terminals. I don't normally do that but I've been wondering lately about internal ground loops between wires and the case. I believe this to be a superior method. I'll let you know my findings.
 

Attachments

  • IMG_2527.JPG
    IMG_2527.JPG
    428 KB · Views: 13
  • IMG_2528.JPG
    IMG_2528.JPG
    499.4 KB · Views: 14
  • IMG_2529.JPG
    IMG_2529.JPG
    517.7 KB · Views: 13
  • IMG_2530.JPG
    IMG_2530.JPG
    376.6 KB · Views: 14
  • IMG_2531.JPG
    IMG_2531.JPG
    369.7 KB · Views: 13
  • IMG_2532.JPG
    IMG_2532.JPG
    382.4 KB · Views: 13
Last edited:
okay... WoW, success! dialed into 25 watts class A with the rest in AB. I've got 100 watts of some serious, *** kicking, wonderful sound.
MY goals for this project was a Class A amp that I'd be comfortable running in summer here in Winnipeg. It gets seriously hot here at times.
Of course my other goals were centered around sound quality and such as we all are on this forum. this amp just makes my speakers move way more then the amp I've been using. it almost like it's alive.

the sound is really quite amazing. I won't bore you with a lot of audiophile babble talk. suffice to say I'm extremely happy and this was 5 years well spent. I'm so grateful for the experience of having this amp in my head for so long until it came out in reality. I had to adjust my plans as I went along, as we all do when undertaking such an endeavor and in the end I can say I'm completely satisfied with how it looks and sounds. And that's a pretty hard response to get from me in the world of audio. some final photos
 

Attachments

  • IMG_2560.JPG
    IMG_2560.JPG
    517.1 KB · Views: 4
  • IMG_2562.JPG
    IMG_2562.JPG
    523.8 KB · Views: 4
  • IMG_2563.JPG
    IMG_2563.JPG
    450 KB · Views: 4