Overview of Solid State Amplifier Brands from where it is impossible to get Schematic

[tiefbassuebertr]

There are an extremly wide range of vintage/legacy and currently brands on world's marked, especially through a lot of new arise brands from China and India. I know only a small range despite the fact, that I work a long time in audio resp. home-hifi.

Especially from the French audio brands it is very hard, to get informations, both from old and currently audio stuff (Micromega, YBA and Cairn-EZO are three examples).
Exactly the opposite concerning English brands, if you find out the earlier developers resp. employers. Crimson, Cambridge Audio and Creek (diyaudio member "X-PRO") are examples.
In most cases the reason for not release the schematics therefore is not the confidential character.
Mostly the real reasons are follow:
1) The only available hand sketching design of the drawed schematic diagram.
2) Because the brand are too ashamed to have sold expensive simple circuit topologies without real special features (Goldmund or Krell could be examples therefore).

Here I will start a list with audio brands, where it did not succeed to get detailled service informations or at least schematics - thank you for supplements for this brand list:

1) Burmester (Germany)
2) Proceed
3) Audio Analyse
audio analyse' - French made amp?
4) Cyrus (Mission) from the model "V" (I-III are available) read in this case the very detailed explanations of diyaudio member "anatech" about
Cyrus III power amp schematic here, but schematics of the later models wanted
5) Micromega
6) CAIRN (CAIRN-EZO)
7) YBA
8) Mark Levinson (except ML-2 and some few other older models, made by John Curl)
9) B&O/Sanyo ICEPOWER
Sanyo/B&O Icepower 200AC Rev.D, schematic about rev. engin., not complete finished

[fojica]

I would add on the list - at least I didn't see any of them
10) Spectral
11) BAT
12) Accupphase - models after 1990, except E-210

[FdW]

And:
13) Somo

[jony]

I have to unknown diagrams.
The first one is Accupphase and and the second one is Mark Levinson

[fojica]

@jony
Maybe you have also the associated models ?
Thanks

[tiefbassuebertr]

Originally Posted by FdW

And:
13) Somo

Until now I have never heard this brand name. Mean you SUMO?
From Sumo there are schematics - go to
SUMO Power Amp
and
http://www.freepatentsonline.com/4229706.pdf
and check google image search by keyword "sumo nine"

[jony]

Well, unfortunately I do not know specific models.
These diagrams was published in Polish electronics magazine, but they only print the brands names not the models.

[jacco vermeulen]

Oldy ML No27.

(input stage is like No23, No23 has 12 output devices/ch. No29 has 6, No27 does 8)

[tiefbassuebertr]

Originally Posted by jony

Well, unfortunately I do not know specific models.
These diagrams was published in Polish electronics magazine, but they only print the brands names not the models.

Which magazines?
perhaps you can post the title so as some cover images of this magazines about
Overview from world's best historical and currently available electr/audio Magazines
Thank you therefore

[FdW]

Originally Posted by tiefbassuebertr

Until now I have never heard this brand name. Mean you SUMO?
From Sumo there are schematics - go to
SUMO Power Amp
and
Audio amplifier
and check google image search by keyword "sumo nine"

Sorry my mistake, yes I meant Sumo. For years I am searching for information about the Sumo "The Ten" (a 50W class mono block) but there is none. For most other models there is (some) information available. The (my) problem is that the pair of “The Ten”s that I have is aging (and I love them), at some moment in time they will breakdown, what then … ?

http://www.flickr.com/photos/fransdewit/tags/theten/

Some correspondence that I had with David from http://davidsaudio.com/

Dear …,

My living room contains a pair of Sumo The Ten mono blocks, I could supply a few nice pictures. My question is, why is it not possible to find service manuals, or at the least schematics of them, I realy love the pair of them, and when (if ever) they break down I would like to be able to repair them.

Regards.
Frans de Wit.

From …

Frans,

Thanks for writing. I would love some pictures if you get the opportunity.

The founder of GAS and SUMO, James Bongiorno, did not publish either service manuals or schematics for any of his products. I think he was afraid of someone stealing his designs; at the least, it forced owners to send their equipment back to the company for any repair work. Now that the companies are gone, it is indeed a problem. ...

Regards,
…