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Alex helge 11th May 2005 06:23 PM

Sumo The Power Schematic
I search the schematic of the Sumo - The Power -
Has anyone a schematic for the Sumo The Power.

I would very thankful

Best regards Alex Helge

Zero Cool 11th May 2005 11:40 PM

I worked on one of these once. Huge pain in the rear. Massively heavy, built monaco <sp> style. the entire chassis is built around the HUGE power transformer. Each channel is a pair of amps in bridged mode with lots of complicated servo circuits etc.

When it worked, it worked great, tons of power, but when it blew, i took out a pair of brand new JBL 15" woofers POOF! what a waste..

Best of luck, i never was able to find a schematic way back when.


Alex helge 12th May 2005 12:15 AM

Sumo The Power
2 Attachment(s)
Hello Zero Cool
thank for your answer

I will buy the Sumo for 1500, but I have never heard a Sumo amp.
The transformer of the Sumo Power to growl lout.

The Speaker membrane to bang at the Sumo switch off and switch on.

Its the tone of the Sumo Power better than the Krell ksa 100.


KBK 12th May 2005 12:44 AM

My limited exposure to Suo amps tells me that the servo control op-amps will need upgrading, but doing so blindly can lead to real issues. Please seek expert advice on that aspect of modification. Also, tons of bad and weak wiring, cheap diodes and capacitors all over the boards. The circuits -tend- to be over complex and rely heavily on feedback for damping. And two of these circuits, bridged, per channel? Eeeeekkk! :xeye:

If i recall correctly, they are re-visions or off-shoots of the GAS amplifiers, all of them being designed by James Bongiorno. Not that he's a bad designer, but I only repair the sound of his amps, not actually listen to them beyond that. I might use one for bass use, for a the same way I might use a Bryston or the like. But I'll never try and listen to one. They just don't sound like music. Very much. :rolleyes:

Just my opinion, like backsides, we all gots one! :D

Bill Fitzpatrick 12th May 2005 03:17 AM


Originally posted by Zero Cool
I built monaco <sp> style.
monocoque - structure in which the outer skin carries all or most of the torsional and bending stresses.

computeruser 12th May 2005 08:08 AM


I rebuilt one of these about a year and a half ago. It sounds
like yours has the same problem as mine did...full DC on one channel. Measure it with a DVM on the outputs. It will be about 100vDC. The designer of this amplifier is James Bongiorno. You can contact him via the Yahoo group "SAE_Talk. If you search that forum you'll find many posts about the Power. (Many of them mine). James will not give out the schematics ( if anybody HAS one, I'd be willing to pay $100 for it). The other posts here are correct: It is a monocoque construction. The op-amps can be upgraded and topics on SAE-Talk cover this. Each channel is a pair of amps in bridged mode with lots of complicated servo circuits. The "transformer growl" you hear is from the full DC on one channel. Mine did it too.

Essentially what you can do to start is this: If you have one good channel, use it as a reference and compare the voltages to the bad channel. Start at the power supply and move outward. The design is fairly straight forward until you get to the servo boards. These are the boards that sit on top of the heatsinks on each channel.

I found this amplifier to be excellent sounding, even better than "The Nine" (another Sumo design) and MUCH BETTER than an Adcom 555 II. It is now in my main system. Good Luck

Alex helge 12th May 2005 11:38 AM

Sumo The Power
Thank Comuteruser for your answer.
Its the price of 1500 for the Sumo Power OK ? I will try to buy the schematic of the Power,too.
The circuit of the Sumo is not easy.
I have not to see the inside of the amp, but I think, I can not buy the components of the Sumo Power.


computeruser 12th May 2005 11:56 AM


I think 1500 euros is a bit much for an amplifier that is not working
and is very difficult to repair. There are 2 people, one in San Diego and the other in Minneapolis who can repair it. You would have to ship it to USA, imagine the cost just for that. James Bongiorno can privide you their names


Alex helge 12th May 2005 11:59 AM

Sumo The Power
Thank KBK for your answer.
I think the Sumo must upgrading, the capacitors and perhaps the diodes must new.

Alex helge 12th May 2005 12:08 PM

Hello Computeruser,
Yes, I think 1500 is very much.
I will wirting to James Bongiorno.

Thank Computeruser

Best regards Alex

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