Build This MoFo!

[Zen Mod]

two different sorts of fun

 

[SDO]

PPS, et. al. Mags, loads of mags. #! /bin/sh # Wed Feb 7 01:28:08 MST 2018 # grab the current PDFs of the R - Pastebin.com

 

[argqsys]

Is there any alternative solution to avoid the usage (or to minimize) of the C2 electrolytic capacitor. As Nelson Pass said "No capacitors anywhere in the circuit...". Especially the electrolytics which killing the music.

 

[Zen Mod]

be aware that same guy put electrolytics in SIT amps

 

[miklos]

Is there any alternative solution to avoid the usage (or to minimize) of the C2 electrolytic capacitor. As Nelson Pass said "No capacitors anywhere in the circuit...". Especially the electrolytics which killing the music.

The simplest way would be to use a single ended output transformer instead of the choke, but the cap sounds just fine to me.

 

[DougL]

Is there any alternative solution to avoid the usage (or to minimize) of the C2 electrolytic capacitor. As Nelson Pass said "No capacitors anywhere in the circuit...". Especially the electrolytics which killing the music.

3 options come to mind.
1. Use a 1:1 transformer instead of L1 and C2. It would require the same primary inductance.
2. Have a transformer wound with superconductor wire. Its the resistance of L1 that places the DC on the output.
3. Find a different circuit that does not require a capacitor.

While there may be a way to make it DC coupled, it violates my simplicity esthetic.

Sorry for the silliness.

 

[flocchini]

Big MoFo with M2 buffer

I believe ZM suggested that to get additional gain for the MoFo use the FE of the M2.

I inserted a M2 FE between the my XP10 and the Big MoFo. Gives me the gain I need and initial listening makes me want to continue listening (and experimenting)

Thanks all

Best

Bob

ZM - more from my heat sink collection - I like these and will use in my next ( and final ) amp

 

[PSz.]

Very nice Bob!

I am on the same path. Currently using Altec 15095As as autoformers in M2 style in front of my 12 volt MoFo. It is a very nice pairing.

Also, the B1 transformer that NP displayed at BAF is basically the same as the M2 front end.

 

[Zen Mod]

and I see you're using motor-run caps for signal .......

 

[argqsys]

I believe ZM suggested that to get additional gain for the MoFo use the FE of the M2.

I inserted a M2 FE between the my XP10 and the Big MoFo. Gives me the gain I need and initial listening makes me want to continue listening (and experimenting)

Thanks all

Best

Bob

ZM - more from my heat sink collection - I like these and will use in my next ( and final ) amp

Can you analyze a little bit this for the beginners like us. What is FE of M2 & XP10 ?

 

[flocchini]

The XP10 is a Pass Labs preamp - It has about 9-10 dB of gain.

The M2 FE in my case is the First Watt M2 with output taken after the !0uF cap. See schematic in the M2 thread.

Hope that helps.

Best

Bob

 

[massimo]

FE stands for Front End, the input stage of a tuner, amplifier, etc.

 

[argqsys]

The XP10 is a Pass Labs preamp - It has about 9-10 dB of gain.

The M2 FE in my case is the First Watt M2 with output taken after the !0uF cap. See schematic in the M2 thread.

Hope that helps.

Best

Bob

Thanks for the prompt reply. Is there any schematic for this adaptation.?

 

[flocchini]

I used the attached schematic which was posted by NP in the M2 thread.
I needed a bit more gain than my Pass Labs XP10 provided, The M2 front end has provided this for me. As pointed out this could also be done with B1 XFMR unit

On the Tea Bag M2 board I populated R1-R5, C1 and C2, Q3 and Q4 and the Edcor PC600.

Output was taken after C2

24V regulated was provided by a supply I had available.

Hope this helps

Nice soundstage both in width and depth. Very involving - makes you want to listen - good detail and female vocalists sound great

 

[argqsys]

Were I can buy from the heat sinks ( the blacks MR's construction).?

 

[zman01]

Mr. Rothacher mentioned that he got the heat sinks from Newark:

http://www.diyaudio.com/forums/pass-labs/313649-build-mofo-5.html#post5217931

Probably these ones:
http://www.newark.com/aavid-thermalloy/db120-20/heat-sink/dp/10WX1014

 

[marconi118]

Is there a simple way to measure saturation current of a choke?

I have EI core autotransformer without gap, I would like to know the max DC current prior saturation to use as MoFo

 

[Zen Mod]

here is the principle

 

[marconi118]

In this atricle we masure the choke at 120Hz AC current

will the saturation DC current be the same?

 

[Zen Mod]

are you sure that you read entire text ?