The MONGREL (supersym II)

[keantoken]

Thanks a lot OS!

You could say it is a Rush... Here is a schematic with it grafted on to your PX. No mysterious unpredictable harmonics! The RC comp resistor can be increased for better specs, but there will be a resonance in the loopgain.

- keantoken

[keantoken]

Um, FYI, the outputs can't run at 234W constant power like that. Probably should lower the rails, and parallel outputs. Look at Sander Sassen's ExtremeA amp for how he did this.

- keantoken

[keantoken]

Hey OS, these caps look really interesting. Not SILVER mica, but mica nonetheless.

SOSHIN ELECTRIC CO.,LTD. -PRODUCT INFOMATION-

Got me thinking, maybe SMD pads should be included for compensation caps?

- keantoken

[ostripper]

Originally Posted by keantoken

Hey OS, these caps look really interesting. Not SILVER mica, but mica nonetheless.

SOSHIN ELECTRIC CO.,LTD. -PRODUCT INFOMATION-

Got me thinking, maybe SMD pads should be included for compensation caps?

- keantoken

Those mica's would be REAL cool to SMD (solder direct) B-C for the miller .... no PCB trace required. As of now, I DO keep the miller VERY close to the VAS devices.

I have finalized my standard documentation package with all the "mongrels". I will include a high quality photo like SNG001 did in his PDF for the PS80. This photo will coincide with the schema/overview for ease of construction. Below is an example (pix 1/2 - PB60LP).

The AX/BX are done but are without pictures (tomorrow). I redesigned these "low end" projects .. ha ha... to accept your "junk parts".The AX was almost the top performer in WAHIB's amp shootout with 200ppm THD @ 1K/40v p-p , so "low end" might be debatable ???
Even with new parts, 2 voltage boards can be had for $25USD. Total for a stereo pair AX or BX + PB60LP's would set you back $45-50USD ...much less if you clean out your junk drawers..

All ZIP's that end in "final" are built and have been throughly ABUSED in the "DOGHOUSE". (CXVB1.2 is next)
BTW , the below PB60 is an EXACT copy of your power board(s).. keen , use as a guide when you get your box...
OS

[sng001]

Hi,

I have made some minor changes to the PB120LP. The Ver.1 board is being built by Repeet and I found more clearance are need for some resisters. I made some minor changes:
More clearance for R85 & R88.
Relocate R98 & R99 so that they no longer live under the inductor.
Space for bigger output inductor.
Fatter ground trace.
Bigger on-board filter caps - snap-in types up to 25mm dia.
Deleted the Capacitor-multiplier option.

The board is slightly smaller.

I will create the BOM & PDF for the new ver 2 of PB120LP.

Cheers, Stanley

[repeet]

Hey Stanley,
I like the improvements on your boards. My semi-conductors arrived yesterday and I have made my PSU inductors. Hopefully I can mount the heatsinks on the weekend and start putting it all together.
Pete.

[ostripper]

Originally Posted by sng001

Hi,

I have made some minor changes to the PB120LP. The Ver.1 board is being built by Repeet and I found more clearance are need for some resisters. I made some minor changes:
More clearance for R85 & R88.
Relocate R98 & R99 so that they no longer live under the inductor.
Space for bigger output inductor.
Fatter ground trace.
Bigger on-board filter caps - snap-in types up to 25mm dia.
Deleted the Capacitor-multiplier option.

The board is slightly smaller.

I will create the BOM & PDF for the new ver 2 of PB120LP.
Cheers, Stanley

Some layout adjustments.... I HATE D96/97 "crooked" !! Move c88/92 right next to the voltage board interface euroblocks , line up the diodes (d96/97) and the resistors (r75/78) vertical near mounting points.

C99/r99 swap with the G1 takeoff point , as close to the OP coil as possible and long jumper over R96b can be 2 short ones , first right above 96b. You dont need the big 6800uF's on board if you have such a big offboard supply like the PS80/100 , shrink to 1k/63v -12.5 -18mm for more layout room to center G1/2 .. this is more important than big caps , especially for G1 (big "dirty pulses from OPS),
you might even add the blueled (V- 68k Resistor/high efficiency).


Otherwise all is good.
What is the CAD software used ?? SNG.... I only use "head" now.
OS

[sng001]

Hi OS,

Thanks for the tips, I will see if I can change the pickup point for G1.

I did a quick change to D97 so that it is no longer crooked.

I use KiCad which is a free software. I found that the learning curve is not too bad, may be because I used the DOS version of Protel AutoTrax before. The default libraries are good but I already added quite a few of my custom footprints to the user library.


Cheers, Stanley

[keantoken]

OS, I got the box today.

Is there any simple way to clamp outputs to a heatsink using ordinary household materials?

- keantoken

[ostripper]

Originally Posted by keantoken

OS, I got the box today.

Is there any simple way to clamp outputs to a heatsink using ordinary household materials?

- keantoken

Kool... USPS is dang kwik!!
I use these... they are $1-2 apiece at a local ACE hardware store... (below pix1)
for doing either low or high power amps you need 1 - 6-32 tap and 1- 4-40 tap.
you ask the helpful hardware man to select the 2 drill bits for these taps ,...drill the holes and the 4-40 / 6-32 screws cost $0.10 cents apiece.. the NJW's mate with the 6-32 screws , the MJE's mate with the 4-40's along with the right insulator (pix2). the ksa3503 can be directly screwed to the HS.(with HS grease). the taps can be used with oil in the holes ... vice grip , slow turn .. back out , slow turn... you get factory results.

If you must , you can directly screw the NJW's to the HS with metal tapping screws using a mica or silicone insulator. the MJE's are more complicated with the shoulder washer shown in ( pix 2). I would suggest the taps from ace as they give the best results.
PS.. you can obtain the shoulder washers for the mje's from used PC power supplies .. usually 4 in each.

If you need more info I will PRESENT my tapping efforts NEXT on this thread... must do my PB60 "doghouse" amp..

OS

If you lack