Build This MoFo!

[e_fortier]

That’s amazing, you went from a MOSFET temp of 100 C down to 59 C by using a different aluminum thickness, good stuff. Below is a before pic showing a curve in the aluminum. Thanks for sharing.

Would be fun to see an updated pic.

BR
Eric

 

[onokun]

A good clamp is angled aluminum as used in mr. Rothacher's build, but I don't have this stuff at hand.

 

[Vunce]

If you have aluminum angle stock, it works very well without bending.

Oops, I was replying while you posted.

 

[onokun]

Yes, that's a better approach, but it won't fit in my configuration of heatsink-pcb, and I want the pcb to stay horizontal.

 

[Eric]

This is a nice and simple solution to your problem! Congrats on identifying a good path forward!

 

[nautibuoy]

Change of plan! The front end of my MoFo project will use a 4P1L...


4P1L (4П1Л) Siberian Gen4 – DHT Preamplifier – Bartola(R) Valves


I remembered I had a few of the required parts and I've bought a pair of Gyrator boards.

 

[Dennis Hui]

My El Cheapo MoFo

I finally finished my cheap and cheerful Mofo monoblocks
and was able to give it a quick listen. I used a preamp
with fairly low gain so power was limited. The sound was
very nice and the build was straightforward.

Thank you Mike!

Dennis

 

[vdi_nenna]

Very Cool Dennis!

Not telling you something you don't already know.
The right preamp makes this amp even better.
Enjoy exploring!

 

[Zen Mod]

 

[Dennis Hui]

Thanks Vince!

At some point, I will build a preamp just for the F4 and Mofo.
(Actually the Mofos were sitting on top of my DIY F4 in the picture.) I'll have to bug
the Notorious MZM about the pumpkin sometime.

I'm currently running 24V/1.7A with the Mofo since I happen to have
those 24V supplies handy. I'm going to try a couple of 20V supplies
later, probably at around 2A bias.

I got a couple hours of listening in yesterday; just flacs ripped from CDs. Gain
from the headphone/preamp was apparently 8dB so I was getting a max power of
just a bit over 3W into 8 ohms. I have a small space and on the tracks I was
listening it was loud enough, with the volume cranked almost wide open.

It sounded really good.

 

[marconi118]

2A with the small chokes ins't it too much?

 

[vdi_nenna]

Hey Dennis,

After I finish the 25W Schade feedback power amp, I'll be building one or two F4s.
Like to know your impressions on sound, at some point, between MoFo and F4.

I don't want to offend anyone (ZM) , but I think the MoFo sounds a lot like the M2.
I've never heard a F4 power amp.

Thanks,

Vince

 

[Zen Mod]

that's Iron in signal chain

 

[vdi_nenna]

1:1 Jensen on MoFo input?

 

[Zen Mod]

everything is possible , even wooden stove

 

[nzlowie]

Hi all, been thinking of building the MoFo to run my mid/hf horns which are around 114db but was put off by the fact that I'd have to build a dedicated pre amp. (Brought a Aska Lender board set anyway).
I just read one of the post saying they got around 3 watts from the MoFo with normal preamp, eg low input. 3 watts would be plenty for me..... This would be cheaper than buying a 2A3 tube amp which was my other choice.

Currently have a DCB1 buffer driving my amps and boards + components coming to build the Korg and also Wayne's BA Linestage.

SS or tube????

Thanks

 

[jolintsai]

Guys,

If I'm using a linear unregulated PSU, how much ripple can MOFO tolerate before showing on my 100dB/w/m speaker? I'm planning for a monoblock PSU as follow:

Bridge --> 33,000UF --> 0.5R --> 33,000UF --> MOFO.

Would the above be sufficient? Based on rough calculation, ripple is about 70-100mVpp.

Thanks guys!

 

[Zen Mod]

you'll be good , maybe even lesser R in CRC

though , you can always resort to CLC

just solve it on the fly

 

[Dennis Hui]

Hi nzlowie,

My DAC output is 2V RMS so with a 8dB linestage I was getting a max of ~3W into 8
ohms.

Wayne's BA linestage has a gain of around 11dB and the same 2V RMS signal will get you around 6W.

Cheers,
Dennis

 

[nzlowie]

Thanks Dennis
That sounds like it should be more than enough, so Wayne's line stage will have enough current / voltage to drive the mofo? What about input impedance, any concerns there?

Looks like the mofo is the next build. Might do this instead of the 2A3 amp.

Any thoughts on this simple amp driving my horns? Killer or average?

Thanks again