mods for son of ampzilla & sae 2400L

From my experience I have found MPS U56's and 57's and 60's along with U06's, u07's and u10's in Ampzilla's and "Sons". What Mike stated for replacement transistors is spot on. The difference between the different U series transistors was mainly the voltage. Be very carefull with what some claim to be replacement transistors for these amplifiers.
 
bielawa said:
i found yesterday on great_american_sound_transistor_cross_reference[1] that gas107 is mpsu06 not mpsu07
and gas108 is mpsu56 not mpsu57 as you stated
which one is correct?


I know that, but they're both from the same series and the breakdown voltages for the 07 and 57 are higher and the rail voltages in the Ampzilla made me a bit leary of suggesting the 06 and 56. Gas had the ability to buy them based on the meeting the spec sheet values.

The substitutes I suggested have no issues that way and the originals are impossible to get with any sense of security that they're actually the real thing. It was more a spec sheet/number kind of thing.

Regards, Mike.
 
madman813

I forgot to mention to be sure to check the bias IC's contact with the heat sink. If the thinner plastic body IC has been used it will NOT contact the heatsink and a shim will have to be used to obtain contact. This has been a problem in both the Ampzilla and "Son" of Ampzilla. This is one of the reasons they can blow sky high. Another possible problem is if the amplifier has been fitted with Tantalum caps. These caps love to short out and start fires on the board. I have personal experience with a 121 board that is damaged very badly as a result of this type of cap. If your boards have Tantalum caps replace them!
 
Re: Re: son of ampzilla mods

Mike

I'm the editor for the hi fidelity museum website and I'd be interested in adding some GAS documentation to the site.

If you'd like to share some scans let me know.

http://www.hifi-museum.com/index.html

http://www.hifi-museum.com/pa/np_index.htm

http://www.hifi-museum.com/lib/lib_fs.htm

MikeBettinger said:






I do have a lot of experience with all the GAS products. I was one of the few Authorized service stations for the gear while they were still around and did a brisk business supporting the stuff once everyone from the company ran and hid when it closed. I have a fairly complete set of all the availible documentation and promotional literature; even a set of original GAS advertizing posters.


This amp would fair quite well if compared to any sanely priced amp produced today.


From your post it's apparent that you must have noticed the Ampzillas and the other family members to be special stuff, which they are. I felt that way years ago when I heard my first Ampzilla and Theadra system. Compared to what was their competition at the time, the GAS gear was light years ahead if not only sound but it was designed and built by very passionate people. Far different in many ways than today's audio business.

Preserve the past as there are enough examples of today's technology that can fill the land fills as they really won’t be worth saving.

Regards, Mike.
 
If you have some digital pics of the Tigersarious you'd like to share let me know. I'd post them here in the gallery along with amps like the Eagle 7A and the dunlap clarke.

http://www.hifi-museum.com/temp/index.htm

burnedfingers said:
We could also bring up the Tigersarious by Southwest Technical Products Corporation. I still own 2) Tigersarious 250 watt mono block amplifiers. When auditioned next to the Ampzilla will fair just as well. The main diference being the Tigersarious had a much better output stage. I've never blown up the Tigersarious amplifiers... [/B]
 
Re: Re: Re: son of ampzilla mods

ZGarage said:
Mike

I'm the editor for the hi fidelity museum website and I'd be interested in adding some GAS documentation to the site.

If you'd like to share some scans let me know.


I'll take a look at the site over the weekend. Other than my time seeming to be limited these days I'll see what I can dig out and scan.

The only reason this sounds difficult is because the original Gassettes were not printed in a normal 8X12 format so I'm not sure how much of a pain it will be to scan them in coherently.

Regards, Mike.
 
Re: Re: Re: Re: son of ampzilla mods

Mike

If you scan them sequentially send them to me as is and I'll combine them.

Regards, Mark

MikeBettinger said:



I'll take a look at the site over the weekend. Other than my time seeming to be limited these days I'll see what I can dig out and scan.

The only reason this sounds difficult is because the original Gassettes were not printed in a normal 8X12 format so I'm not sure how much of a pain it will be to scan them in coherently.

Regards, Mike.
 
Joe

The insides are the good part :) , thats what people want to see.

The transformer, capacitors, boards and transistors are the good stuff.

A shot from the front, top (without cover) and back would be ideal. 1024 x 768 resolution.

Also if anyone knows the history of the company and any info about the designer I'll post it.

Submissions welcome here:

http://www.hifi-museum.com/scans_frame.htm

Thanks,
Mark

burnedfingers said:
Mark,

Unfortunately I am missing the covers to the amplifiers. I could send you pictures of the front and back if you are still interested.
The Tigersarious lacks the glamor of the Ampzilla.

Regards,
Joe
 
A question for you

Mike,

Bypass all electrolytic caps on the driver boards with small silver mica or mylar. Bypass the filter caps in the power supply with small electrolytic caps also(try about 33mfd/100volt) and .1's

You won't succeed in making them sound any better by jacking up the bias setting on these amps. I've measure the thd and Imd of the stock bias settings and increased bias setting.

Do you repair SAE amps? If so I have a 2400L which I would like you to upgrade per your earlier rhetoric. Amp is in perfect working order.
 
Hi Mike. I am looking for one original TO66 GAS105. driver. Also if possible but not urgent one GAS 104A and one GAS 103A. Do you know who might work on these boards and replacing them all might have some orphans? My board is the 121F. Any and all suggestions greatly appreciated.
Thanks Regards Paul.
I forgot Bias IC 100A would be great as well...