Alpha series

[Plimpington2]

I have accumulated a nice, representative alpha collection, which I enjoy quite a bit. I do my own wrenching, and so I am often looking for information on here. There are lots of alpha threads, which attempt to accumulate service/technical information in one place - but they are several. I wish we had a single sticky that did this. But also that was “curated” for lack of a better term so we can readily rely on it.

I may have some technical information to contribute since I have and have been inside of (or can be inside of) the following alpha units (get your minds out of the gutter!!)

907dr
907kx
607Mos Limited (this thing is GORGEOUS)
G99X
X701
B2301L
C2301
907i

In any event, one thing that I found in an earlier thread that struck me as not quite right was a description of the LAPT OPT’s that go in the high end alpha series. The LAPT-23 devices were described as being found in all the alpha 907 series amplifiers (dr, kx, mr. . . etc.). This is not the case. The LAPT-23 series OPT’s are in MT-200 packages. My KX and DR have LAPT-2 OPT’s, which are in TO-3P packages. The MR (which I don’t own but have serviced) also uses LAPT-2’s.

 

[JimEGR]

The more Alpha documentation the better. If you read a mistaken claim in another thread, please correct it. These posts are our reference guides.

I would caution you on posting technical documents here though. AK has some asinine and backwards policy about where documents get posted. I had built a few collaborative Alpha and other threads here at one time that included scans of tech manuals I spent quite a bit of money on importing from Japan, and generous contributions from other members too. Following the bizarre policy that threads with documents are only allowed in Digital Docs forum, my threads were removed from the Sansui light of day here to the Siberian banishment of Digital Docs forum - where threads go to die.

If AK were less serious about Gestapo policy enforcement, and were more serious about building our technical documents library it would allow technical topics and documents to flesh out and flourish where they are most likely to - in their respective manufactures forum. Have the mods remind folks to contribute the documents to the AK Library and the knowledge will live forever here.

And yes I've made my case to the powers that be here. And no nothing changed. Not a rant just the truth.

As for other good threads discussing Alpha technical information, anything posted by @fojica or containing contributions from him are a technical gold standard.
Here's one -

F

Thread 'Sansui Alpha - debunking NRA series'

Dec 20, 2022

Ok, so let's say that I'm still in the Christmas giving mood, so this would be a second "gift"

To start with a bit of history as this seems unclear for some people, Sansui Alpha's were actually born in 1982, with B-2301 power amplifier. Indeed, not named "Alpha" back then, but "X-Balanced".
Strictly from a marketing perspective, their amps were named "X-Balanced" in 1982-1985 interval, then in 1986 that was changed to "Alpha". Technically being the same "heart" as before, so kind of "the same Mary wearing a different hat".

As a parallel joke, later on from 1990 onward "Mary" started...

• fojica
• Replies: 19
• Forum: Exclusively Sansui

• 

 

[bolero]

I didn't even know there was a digital docs forum, thx for the headsup

I get cloudflare errors trying to access the AK database

 

[jefferylhenr]

I have the original Au-907 alpha, the Au-607mr and the Au-607 nra. The 907 I brought back from the dead with new drivers and outputs and it’s stable as a Baptist minister. This was after working myself up from the late 60’s era and it’s been quite the journey. Both the MR and NRA had signal dropouts which were fixed with resoldering, lots of switch cleaning and relays. For pure listening excitement, my AU-X1 driven by my Accuphase class A C-200v in direct mode might be my best Sansui. Yes and thats compared to the BA-3000, BA-3000, AU-20000. The amplifier section in the AU-X1 just has something (for me) even the Alphas don’t. And, I like the sound of the MR better than the NRA.

I am somewhat ruined however by my Class A Accuphase and Luxman’s. Wandering through these more modern units without service manuals or schematics means one must keep good documentation and take your time. The class A has something the even the alphas don’t for my ears.

I will probably spend the near future pursuing the Class A world.

 

[pete_mac]

I have accumulated a nice, representative alpha collection, which I enjoy quite a bit. I do my own wrenching, and so I am often looking for information on here. There are lots of alpha threads, which attempt to accumulate service/technical information in one place - but they are several. I wish we had a single sticky that did this. But also that was “curated” for lack of a better term so we can readily rely on it.

I may have some technical information to contribute since I have and have been inside of (or can be inside of) the following alpha units (get your minds out of the gutter!!)

907dr
907kx
607Mos Limited (this thing is GORGEOUS)
G99X
X701
B2301L
C2301
907i

In any event, one thing that I found in an earlier thread that struck me as not quite right was a description of the LAPT OPT’s that go in the high end alpha series. The LAPT-23 devices were described as being found in all the alpha 907 series amplifiers (dr, kx, mr. . . etc.). This is not the case. The LAPT-23 series OPT’s are in MT-200 packages. My KX and DR have LAPT-2 OPT’s, which are in TO-3P packages. The MR (which I don’t own but have serviced) also uses LAPT-2’s.

Spot on, and I hadn't seen that earlier info which is clearly incorrect.

Thanks for noticing and correcting it for the record!

 

[mjs1]

Hi Plmpington2.

You might be referring to my posting on the Alpha transistors in the thread a few listings up “Sansui Alpha series settings and notes”. This information was gathered from other posts and attributed. I cannot vouch for their accuracy. Would you be so kind to post any discrepancies you have found in that thread as your findings based on your personal experiences, as you have here. It may be too late to correct that posting but the information you provided belongs there as well.
Thank you and best regards.

Marc