Ok, here it is. 100W per ch (before clipping). I owe something to this forum.

Hope there is some more HH love out there.

wow. amazing. thanks! what a great forum.
I thought for sure I was crazy or was missing something. I have to put this thing back together and take some voltage measurements to add to the sch. I'll post the completed sch after that.

Incidentally, this is Lee Jackson's Perfect Connection SP-1000 design. I saw some guys over at Ultimate Metal forum had cloned it, but never published anything.

Yes, the power supply has two sep rectified secondaries..but no more filtering after bridge (just like QSC design posted).
Thanks again!

Hi
I'm usually a lurker, but have been getting deep into SS amps for awhile now. I have HH's and a Trace Elliot, and an old Heathkit TA16 I rebuilt. Love them all. My HH MOSFET Studio 60 'Power Baby' is my go to amp.

But I found something peculiar....I've attached the schematic and before I state what the amp model is...I need to know what this is a derivative of. It appears to modulate the rails...
I have checked, double checked, and compared both ch's (it's a 2 ch amp). It's a single sided pcb, very spartan and spread out (altho the layout and routing are worse than amateur).
It is a guitar amp. Has anyone seen anything like this? How does it work. It does work, I had it running and it's 100W into 4ohms!

Once I have complete schematic done (incl power supply), I'll be happy to contribute it to schematic section...and reveal make/model (it's well out of production).
Thanks
all.

phatt...I really like reading your posts and ideas. I lurk here because I'm convinced that you don't need a full on tube amp to get great sound and feel.

That being said....I think you are onto something. Have you seen Merlin Blencowe's paper on low voltage triodes?
http://www.valvewizard.co.uk/Triodes_at_low_voltages_Blencowe.pdf
I was going to breadboard this up and take a look at it's behavior at clipping and insert it into my Studio 60's power amp (at some point when all my day job crap is caught up). But I like the idea of having an opamp front end.

One thing you might try is combinations of germanium diodes and 5mm LEDs. I think asymmetrical clipping has a nicer 'just at the edge of clipping' sound.

I like 741's because they are low BW and lo-fi...as guitar amps should be. The HH Studio 60 uses 741s and Harris quad 741s...and sounds stellar.

Quote from: kikey on January 05, 2010, 08:20:59 PM
Hi

I am interested in the sustain circuit in the HH IC100S.
Anyone here know where to find a schematic ?? 

Thanks,

go to http://www.majelectronic.co.uk/ and ask for it. they only ask for a small fee (literally pennies considering what you're getting)....they do paypal
I sold my 100S and my Burman 2000 to Mark Thwaite (Peter Murphy, Gary Numan, The Mission, etc)...BUT, I have a VS head that I'm refurbing.....another stellar amp imho (my MOSFET Power Baby is my #1)

Hi. I'm a noob here, but have been working on HH amps for a bit. In fact, they are my fav amp now. I have a MOSFET Studio60 'PowerBaby' that rivals some SLPs in my book.

The power amp rails on the IC100L are +/-48V (given ideal mains voltage...and that can vary). These are simple PT>rectifier>cap unregulated supplies...so the wall voltage has a good deal to do w/ power rail voltage.
The preamp rails are +/-16V, simple resistor>zener>cap type...so he is prob referring to that.

Superfuzz...THE most common problem w/ these amps are the two main power supply filter caps (4700uF 50V). Every HH I've been in hasn't had these caps replaced...and either leaking electrolyte out of the plugs or the plugs are about to burst. I bought a 'not working' IC100S...and it had one cap blown out...and took one of the output transistors (2N3773 usually). I recapped and replaced both transistors....but the one thing that stood out.....when I plugged it into the wall here (120V+)...the power rails were just above 50V. I used 5600uF 100V caps, so is a non issue.
The second thing is the pots. Any time these get even a little dirty...the tone goes all to *s!!t*. You need to clean them thoroughly. Douche w/ non-residue cleaner first. If they have the 'feel grease' in them...you'll have to disassemble them and clean just the carbon track...or loose the resistive feel of the pot.

All this to say....check the big caps first.....replace if they are original. Clean the pots. Then check the outputs of all the opamps. Unfortunately...this thing uses 4739 opamps in addition to xx741 opamps. If any of the 4739s are bad....well...there are a few Raytheon RC4739s on eBay for big$.

Incidently, I just sold my IC100S to Mark Thwaite...who is Peter Murphy's guitarist. That guy can play.....