will pay for Belles 1 Series amp info & Schematic

[gp4Jesus]

thread title says it all.

Have DC problem to trouble shoot in 2 units.

Both amps, under the same circumstances. 1 produces very faint clicks, the other pops loudly in left channel.

Hafler xl-280; direct coupled-dead silent!

REALLY want the schematic.

Thnx advance tony

[tiefbassuebertr]

Today I will ask for navigation instructions to find the appropriate download aera about
www.powermodules.com
Unfortunately I am not able to find it without help.
At most websites such aeras not so easy to find like at Crown's homepage.
I need schematics of several currently available and vintage models (quickly the reference power amp 350A).

[gp4Jesus]

I have two Belles 1 Series power amps; appropriately nick named "Clicker" & "Popper."

Clicker "clicks" & Popper "pops when changing surround sound decoding or some operations on DVD player.

Clicker's ser#: 134; Popper's ser#: 228. This is importan because the driver board's layouts differ considerably.

DC offset: Clicker's 33mv & -74mv; Popper's 150mv & 1.03Volts! YES you read that right 1.03V!

I sent an email to www.powermodules.com requesting a schematic though I don't it to pan out.
thanks tony

[gp4Jesus]

Bottom line: don't expect any schematics.

Spoke to Dave Belles himself, today. He considers schematics intellectual property & won't hand out or sell them.

If you DO get one, my PP account is ready.

Tony

[tiefbassuebertr]

Originally Posted by gp4Jesus

Bottom line: don't expect any schematics.

Spoke to Dave Belles himself, today. He considers schematics intellectual property & won't hand out or sell them.

If you DO get one, my PP account is ready.

Tony

Thank you for that info. This means "reverse engineering" in case of wanted schematic.
Fortunately the topology by my model "350A Reference" is easy (cascoded differential amp with current mirror and dual BjT "LM394" in the front end so as audio lateral MOSFET's from Exicon in the output).
But I don't know the exactly recommend value for the idle current. I guess 100-150mA/each Exicon MOSFET pair.
Additional an outdoor inrush current limiter is necessary to switch on six stereo devices of that model at the same time.

[gp4Jesus]

Originally Posted by tiefbassuebertr

This means "reverse engineering" in case of wanted schematic.

Yeah, "reverse engineering." Compared to a Hafler XL-280*, the Belles is VERY simple. I scheched out the PCB on 11X17 paper & drew in the components.
* using 280 schematic to help me

Unfortunately, I can't figure out what a couple of components are. One of the driver transistors has colored stripes accross it; the other, marked 41011. Can't locate info on the 41011. Started a diy thread for answers.

Can't make out what two tan colored things are, either radial caps or resistors. I expect to remove to test. Diodes have a mark or stripe at cathode end, right?

Finally I may have "bit off more than I can chew" as my EE background is limited compared to most, but that won't stop me from trying.

Originally Posted by tiefbassuebertr

...topology: cascoded differential amp with current mirror

Sorry I don't know what this means. But for all either of us knows, Belles may have used similar if not the same topology, just newer components in your 350! Google Rod Elliot. He does that in many of his power amps designs.

Originally Posted by tiefbassuebertr

and dual BjT "LM394" in the front end...

Has 3 transistors (FETs?), 8099s* & 8599s*, per side before the drivers (41011 one side, the other??); all discrete components, no chips;
* appears to have 1 8099 & 2 8599s on one side; 2 8099s & 1 8599 on the other. Finishing the schematic may prove otherwise

Originally Posted by tiefbassuebertr

audio lateral MOSFET's from Exicon in the output).

6 bi-polars per channel in output.

Originally Posted by tiefbassuebertr

But I don't know the exactly recommend value for the idle current. I guess 100-150mA/each Exicon MOSFET pair.

I think you guessed right. Click here for a long-winded confirmation. My Belles doesn't have a bias POT. If I can get DC offset problem licked, that should be easy. I noticed a 1 or 2 resistors w/out a "twin."

Adjusting the Bias Of Your Amp [English]

We both love our awesome amps. I understand Belles' attitude for your late model amp. Mine are 25 years old!!

thanks for reading this far; Keep me posted on what you learn

cheers tony

[h_a]

Have DC problem to trouble shoot in 2 units.

Any potentiometers on board?

[gp4Jesus]

Originally Posted by h_a

Any potentiometers on board?

None! I'm certain of it. read my previous post

tony

[tiefbassuebertr]

Can you post some pictures (outside front/Rear/top view inside) ??
I cannot find any informations about the amp model "1 Series" from Power Modules/David Belles - obviously there are only few devices produced (maybe first power amp device from David Belles).
41011 sounds like custom made BjT's from RCA/Harris - check also the logo
8099/8599 could be that type:
http://www.classiccmp.org/rtellason/...ta/ksp8098.pdf
http://www.classiccmp.org/rtellason/...ta/ksp8598.pdf
http://www.datasheetcatalog.org/data...la/MPS8598.pdf

The first steps you must perform is follow:
1) create schematic diagram
2) replace all electrolytic caps - if still DC offset present,
3) measuring of the DC conditions by shorted input and
4) starting the actually trouble shooting

concerning the not presently variable resistor: either at this place was put in a normally resistor after adjusting a potentiometer (NAD 3130 works in this kind) or an idle current servo circuit (instead a commonly used Vbe multiplier) is in use.
I guess, the topology is a normal differential input amp without current source and current mirror so as one stage VAS without Ube current source but with bootstrap cap to the output like "Citation 12"
http://www.passdiy.com/pdf/citation.pdf (Fig 7)
Pass mosfet citation 12 clone

[gp4Jesus]

Originally Posted by tiefbassuebertr

Can you post some pictures (outside front/Rear/top view inside) ??

I'll post pics of PCB too-Popper partially disassembled to draw schematic.

Originally Posted by tiefbassuebertr

I cannot find any information about the amp model "1 Series" from Power Modules/David Belles - obviously there are only few devices produced (maybe first power amp device from David Belles).

Yeah you won't any info on Power Modules.com about these or any other pre early-mid 90s designs*. Several times a year you'll see any of these come up for auction on ebay-that's where I got Popper, my 2nd one.
* 100, 200, Class A mono blocks about 2 weeks ago, "2"-the baby brother to "1"

Originally Posted by tiefbassuebertr

41011 sounds like custom made BjT's from RCA/Harris - check also the logo
8099/8599 could be that type:

http://www.classiccmp.org/rtellason/...ta/ksp8098.pdf
http://www.classiccmp.org/rtellason/...ta/ksp8598.pdf
http://www.datasheetcatalog.org/data...la/MPS8598.pdf

the 41011 is screwed to a heat sink that's then screwed to the PCB. I'll have to look on the heat sink side.

I remember a Motorola symbol on either 8099 or 8599

Originally Posted by tiefbassuebertr

The first steps you must perform is follow:
1) create schematic diagram

working on it-tough w/9 kids! I squeeze in editing (a text file)between crisses then copy/paste to a reply window.

Originally Posted by tiefbassuebertr

2) replace all electrolytic caps

Should be easy-only 3. Then check offset again? Here's where I'm fuzzy on your advice

Originally Posted by tiefbassuebertr

If DC offset still present,

measure w/shorted inputs (?) If offset still bad, then start the trouble shooting?

Originally Posted by tiefbassuebertr

idle current servo circuit
Vbe multiplier
differential input amp* without current source** and current mirror...
VAS without Ube current source...bootstrap cap to the output...

I've heard the XL280 use this*. Except for **, I do not know what any of these other terms mean. I see VAS in many other amp threads-haven't gotten to asking what it means.

Originally Posted by tiefbassuebertr

http://www.passdiy.com/pdf/citation.pdf (Fig 7)
Pass mosfet citation 12 clone

I look forward to checking these links. a previous reply sent me a link that suggested info for the 41011, but no trace to its twin
I'll PM the schematic to ya.

thanks a million for your help,tony