Build This MoFo!

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#2,201
Zen Mod said:
for unipolar supply, look at first B1(just N polarity JFets) iteration and then you can use either 19 or 24V without changes ; take care to not use limiting output resistor ( was 1K in first one)

for proper wiring of Edcor = look at M2 threads

regarding Rin- series resistor is usually much smaller than that one shunting gate to "gnd" , so that bigger one (then) dominates
so , Rin is in range of 1M

if you have more dilemmas , make some effort and post schematic of you r intended combo . MS Paint or any other small proggy is good enough for editing small schematics
Click to expand...

I'll see if I can sketch up a schematic of my plan. I didn't realize the M2 wires the Edcor as an autoformer with both windings connected. Edcor makes a 10K:150 transformer, might be good for more gain if wired backwards.
 
#2,203
Good morning gentlemen,
Building two Mofo mono block is my new audio project and I start to list all components to order...
I would like to use the best of it and I am feeling a little bit lost concerning resistors ( too many reference, different temp. coefficient, etc)..
Please could you advise me with precise references ( Vishlay n°…)
About heatsink, do you have, please, link to interesting products. I am looking for efficient and beautifull sculptural extrusion. I would like to build attractive design. 🙂
I thank you really much.
Musically yours
TYM
 
#2,204
something like this?

black anodised and dusty
 

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#2,207
TYM said:
..I would like to use the best of it and I am feeling a little bit lost concerning resistors ( too many reference, different temp. coefficient, etc)..
Please could you advise me with precise references ( Vishlay n°…)
Click to expand...

You do not find such high quality resistors in many commercial amplifiers

https://www.mouser.fr/datasheet/2/427/cmfmil-109690.pdf

Vishay Dale RN60 or RN65 or CMF , RL cost more..

https://www.mouser.fr/Vishay/Passiv...zekj6Z1yzekiwZ1z0zls5Z1yzuosyZ1yzv7erZ1yzveax
 
#2,209
@ TYM
This Vishay Dale resistor has great audio quality / specifications / price ratio.
It's easy to spend money on more exotic boutique resistors like non inductive Mills wirewound, Tantalum,Z-bulk foil etc.
but You need experiment by yourself and find conclusion is worth or not.
 

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#2,211
If anyone is interested in building one i have this laying around.
2x Hammond 193v
2x Meanwell PS
2x Build PCB (mosfet on the backside)

Shoot me a PM with a offer. US only please

:cop: Mod note. This has now been sold to mordikai. 24th Aug 2019
 

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#2,214
I see MOT 's recommended as a choke for the Mofo. Off course those would be transformers with a 110 V primary, would an European MOT with a 220 primary be OK? I measured one and DCR is 1,6 Ohm. Inductance I dont know yet.
Because those MOT's are welded, not very firmly, wouldnt it be better to saw them open, rewind with different wire an add an air gap?
 
#2,217
stevenrotterdam said:
Because those MOT's are welded, not very firmly, wouldnt it be better to saw them open, rewind with different wire an add an air gap?
Click to expand...

Yes, someone else did this and posted images some time ago. I'm thinking he reported just using a hacksaw on the poorly welded seams - they open up pretty easily (though, I haven't done this myself).

DCR above 0R5 or so will only lead to more heat than necessary in the transformer.
 
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