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G.A.S. Ampzilla

Machineghost

Machineghost

Ghost in the machine
Good day guys

I need some serious help and pointers. I have a GAS Ampzilla (Serial number E103217) with one channel blown.

Reading up on the web I fear that repair will be close to impossible considering these amplifiers were so complex and used proprietary parts.

Any pointers on substitute parts for i.e. the GAS114/5 (Motorola) and the GAS100A (Motorola) IC?
 
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Mouser carriers the MPQ6002 which will drop in for the GAS100A/MPQ6001 (its a higher gain bin). As for everything else (thanks to Gasworks Audio):

GREAT AMERICAN SOUND TRANSISTOR CROSS REFERENCE
GAS 101 = 2N5631 OR MJ15022 OR 24
GAS 108B = MPS8599
GAS 101B = 2SD424 OR 2SD555
GAS 108C = 2N5401
GAS 101C = 2SC1586 OR 2SD424 (NPN)
GAS 109 = MPSU07
GAS 102 = 2N6031 OR MJ15023 0R 25
GAS 110 = MPSU57
GAS 102B = 2SB554 OR 2SB600
GAS 112 = 2N5088
GAS 102C = 2SA909 OR 2SB555 (PNP)
GAS 112C = 2N5551 (NPN) match hfe to compliment
GAS 103 = 2N6316 OR 2SD525
GAS 114 = 2N4401 (NPN)
GAS 103B = 2SD525
GAS 114A = 2N5210 match to compliment
GAS 104 = 2N6318 OR 2SB595
GAS 115 = 2N4403
GAS 104B = 2SB595
GAS 115A = 2N5087
GAS 105 = 2N3584
GAS 116 = 2SD613 OR MJ15028 low hfe <150
GAS 106 = 2N6421
GAS 117 = 2SB633 OR MJ15029 (PNP) low hfe <150
GAS 107 = MPSU06 OR 2N5551 match hfe
GAS 118 = 2SB554 (PNP)
GAS 107B = MPS8099
GAS 119 = 2SD424 (NPN)
GAS 107C = 2N5551
GAS 100 = CA3086 Transistor Array (5 NPN)
GAS 108 = MPS56 OR 2N5401 match hfe
GAS 100A = MPQ6001 OR MPQ6002 ( 4 transistor array, complimentary)

DIODES ACROSS AMPZILLA EMITTER RESISTORS ARE 1N5821

NOTE: ALL VERSIONS OF
GAS 107 CAN USE JAP 2SC2240 ( NOTE THE DIFFERENT PINOUT ) ALSO
GAS 108.. 2SA970
BEST STABILITY IS ACHIEVED WITH MATCHED QUAD SETS WITH HFE IN THE 150 TO 250 RANGE.
ALL VERSIONS OF THE
AMPZILLA CAN USE MJ15022 / MJ15023 AS THE OUTPUTS.
USE ONLY THE MOTOROLA TRANSISTORS THOUGH
DO NOT USE REPLACEMENT TYPES FOR ANY ORIGINAL TRANSISTORS IE: NTE, SK, ECG, ETC.
THE FETS USED IN THE THAEDRA/THOEBE LINE AMPLIFIER CAN BE REPLACED WITH 2N5459 N-CHANNEL 2N5462 P-CH (MATCHED AS BEST AS YOU CAN FOR FETS)
THE BIAS SETTING FOR THE AMPZILLA IS 30MV ACROSS THE EMITTER RESISTORS OF THE OUTPUT TRANSISTORS
THE SON OF 22MV SAME PLACE.
OFFSET IS ALWAYS SET FOR .000V +/- .015V
DRIVER TRANSISTOR SHOULD ALSO HAVE HFE'S LOWER THAN 200 FOR BEST STABILITY


For more information, e-mail us at gasworks@gasaudio.com <mailto:gasworks@gasaudio.com>
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Bottom of Form 1
This page last updated on Feb, 2002.
Copyright (c) 1996-1999 GASWORKS
Names used throughout the GASWORKS sites are trademarks of their respective companies.
 
Thanks for the info.

One of these days I have to dig out the "core" I got and rebuild it.
This will help a lot!
 
FootFungus said:
Mouser carriers the MPQ6002 which will drop in for the GAS100A/MPQ6001 (its a higher gain bin). As for everything else (thanks to Gasworks Audio):

GREAT AMERICAN SOUND TRANSISTOR CROSS REFERENCE
GAS 101 = 2N5631 OR MJ15022 OR 24
GAS 108B = MPS8599
GAS 101B = 2SD424 OR 2SD555
GAS 108C = 2N5401
GAS 101C = 2SC1586 OR 2SD424 (NPN)
GAS 109 = MPSU07
GAS 102 = 2N6031 OR MJ15023 0R 25
GAS 110 = MPSU57
GAS 102B = 2SB554 OR 2SB600
GAS 112 = 2N5088
GAS 102C = 2SA909 OR 2SB555 (PNP)
GAS 112C = 2N5551 (NPN) match hfe to compliment
GAS 103 = 2N6316 OR 2SD525
GAS 114 = 2N4401 (NPN)
GAS 103B = 2SD525
GAS 114A = 2N5210 match to compliment
GAS 104 = 2N6318 OR 2SB595
GAS 115 = 2N4403
GAS 104B = 2SB595
GAS 115A = 2N5087
GAS 105 = 2N3584
GAS 116 = 2SD613 OR MJ15028 low hfe <150
GAS 106 = 2N6421
GAS 117 = 2SB633 OR MJ15029 (PNP) low hfe <150
GAS 107 = MPSU06 OR 2N5551 match hfe
GAS 118 = 2SB554 (PNP)
GAS 107B = MPS8099
GAS 119 = 2SD424 (NPN)
GAS 107C = 2N5551
GAS 100 = CA3086 Transistor Array (5 NPN)
GAS 108 = MPS56 OR 2N5401 match hfe
GAS 100A = MPQ6001 OR MPQ6002 ( 4 transistor array, complimentary)

DIODES ACROSS AMPZILLA EMITTER RESISTORS ARE 1N5821

NOTE: ALL VERSIONS OF
GAS 107 CAN USE JAP 2SC2240 ( NOTE THE DIFFERENT PINOUT ) ALSO
GAS 108.. 2SA970
BEST STABILITY IS ACHIEVED WITH MATCHED QUAD SETS WITH HFE IN THE 150 TO 250 RANGE.
ALL VERSIONS OF THE
AMPZILLA CAN USE MJ15022 / MJ15023 AS THE OUTPUTS.
USE ONLY THE MOTOROLA TRANSISTORS THOUGH
DO NOT USE REPLACEMENT TYPES FOR ANY ORIGINAL TRANSISTORS IE: NTE, SK, ECG, ETC.
THE FETS USED IN THE THAEDRA/THOEBE LINE AMPLIFIER CAN BE REPLACED WITH 2N5459 N-CHANNEL 2N5462 P-CH (MATCHED AS BEST AS YOU CAN FOR FETS)
THE BIAS SETTING FOR THE AMPZILLA IS 30MV ACROSS THE EMITTER RESISTORS OF THE OUTPUT TRANSISTORS
THE SON OF 22MV SAME PLACE.
OFFSET IS ALWAYS SET FOR .000V +/- .015V
DRIVER TRANSISTOR SHOULD ALSO HAVE HFE'S LOWER THAN 200 FOR BEST STABILITY


For more information, e-mail us at gasworks@gasaudio.com <mailto:gasworks@gasaudio.com>
Top of Form 1

Search for:

Bottom of Form 1
This page last updated on Feb, 2002.
Copyright (c) 1996-1999 GASWORKS
Names used throughout the GASWORKS sites are trademarks of their respective companies.
Click to expand...
Thank You Very Much! Ampzilla will live again!
 
That's it? What are you working on and what's wrong with it? Curious GASGEEKS want to know!

Craig
 
llwhtt said:
That's it? What are you working on and what's wrong with it? Curious GASGEEKS want to know!

Craig
Click to expand...
I have a Son of Ampzilla and one channel was out. I am also having the output RCA jacks replaced as they were intermittent. The cross reference was very helpful. As soon as I told my repair guy what the parts were he knew right away what to do.Thanks again.
 
Make sure the RCA input jacks are grounded to the chassis, it's the ground reference for the driver boards.

Craig
 
I have a spare SanKen "O" grade GAS118C and a couple of GAS117, where do you want them sent? Is the bias IC OK, GAS100A or MPQ6001?

Craig
 
Last edited:
Before I send this package out are you sure the bias IC is OK? If it isn't the outputs will get wiped out again.
 
You should have sent your address via PM. Your address is available for all to see. I'd advise you delete that post.
 
Last edited:
USPS tracking says delivered to mail box at 4PM on Wednesday. If you didn't get them you are welcome to come and get some more, I'm not sending anymore.

Craig
 
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