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Sansui C/B 2105 Vintage

This thread made me think of something funny:

how can a preamp with

no tone controls
< 0.0005 % THD
0.003 % Cross modulation distortion

sound different from another preamp with

no tone controls
< 0.003 % THD
0.003 % Cross modulation distortion

?

The sum of it's parts and a little bit of magic?
 
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I can't offer much in the way of comparative analysis, but will say you have a remarkable collection of rarities there. Especially the 2105 combo, which I would not split up under any circumstances. If you find it doesn't meet your needs in terms of sound and performance, then they should be sold off together as a matched set.

The C-2301 is in a class of it's own, and it would be a really tough call to get rid of it, in my opinion. I'd sooner keep it, and mate it to a capable power amp (of which toy already have a couple of good options), or just bite the bullet and get a B-2301 to go with it. But I recognize you are trying to pare things down, and also want to settle on gear that isn't physically difficult to handle, if the need arises. That makes the B-2301 kind of a non-starter.

The AU-X1111MV is another model in it's own class, but I can understand if you aren't as enamored of the MOSFET sound. And being an integrated amp, it is still something of a compromise over separates, even as good as it is.

If @mjs1 has some help to move and sell some of his gear (like that AU-X1111) he could leverage that same assistance in setting up a B-2301 as part of this final configuration. Once it's set, he's set.
 
The sum of it's parts and a little bit of magic?

heh, yes: Rikens, copper, silk caps, bitumen, teflon?

Those were specs from some preamps in this thread. I guess there are circuit differences too but not all SM are available to compare

It reminds me of Hirano-san saying the reviewers were impressed he was bold enough to add "source direct" bypass option to the C-2301
 
Thank you all for the replies. I’ll get back to this thread with my thoughts when I have a chance later in the day.

Just some random comments.

As for the AI slop, it is interesting but I won’t make decisions based on it. For example, despite what it says, the Renaissance 90s, unlike some other Infinities, are not difficult to drive.

I would love to match the C-2301 with a B-2301l but I am afraid that my collecting days are over. I won’t part with it and use it with my B-209.

Marc
 
Thank you all for the replies. I’ll get back to this thread with my thoughts when I have a chance later in the day.

Just some random comments.

As for the AI slop, it is interesting but I won’t make decisions based on it. For example, despite what it says, the Renaissance 90s, unlike some other Infinities, are not difficult to drive.

I would love to match the C-2301 with a B-2301l but I am afraid that my collecting days are over. I won’t part with it and use it with my B-209.

Marc
>>>cough<<<<. You have a B-209??!
 
Personally I would keep the C-2105 and B-2105 paired together.
Sell the AU-X1111 if your not in love with it.
Same with the B-2102 mos. Sell.

I would also like you to entertain the thought of selling the C-2301 to another dedicated Sansui collector that has a B-2301 or B-2201 that needs a C-2301 to complete a set.
Don't sell the C-2301 to just anyone. Make certain that they actually have a B-2301 or B-2201 to pair it with.

I don't hear the synergy or know if pairing the C-2301 to a B-209 is the best use of a C-2301.
 
To DB-7: I have had someone with a B-2105 reach out to me for the C-2305 preamp and he will get it if I decide to split them. I am very confused right now.

Not having a golden ear, I am not sure that I could tell the difference between my excellent preamps and I don’t have the energy/ enthusiasm to rotate them nor can I do A-B comparisons.

A lot of this, for me, comes down to nostalgia. My first Sansui was an AU-717. I had it restored and would never part with it. It sounds pretty good to me, though I think power of suggestion with appearance, looks, price, and sentiment affect a lot of my and others evaluations. Nor would I part with my 9500 given its history, or my X911dg. The X911really sounds sweet using its dac and headphones. It is great with speakers too. Bluesky is a great fan of the X901 (a bit earlier, also X balanced) and to tell the truth in A-B comparisons I don’t think that I could differentiate between them. My desire to get AU-X1111 was influenced by Steen. Steen was from Copenhagen, was a regular AK contributor, and died several years ago. He may have been or worked as a Sansui dealer and did run Sansui parts shop. I bought an X911 face plate and some other things from him but I would part with this one.

I’ll post this now but continue my rambling.
 
Continuing…

I don’t want more amps. Despite the hype (which I don’t doubt is true), I can’t see looking for a 1985 B-2301L in good cosmetic condition (which I believe is on the order of 42 kg), paying for and risking shipping, dragging it around for restoration (old components, Sansui glue) and getting it in the line up. I can’t help but be skeptical about it in comparison to the newer amps of the late 1990s given the changes in topology.

Getting back to what else I really like there are the 07 Anniversary, the 907 Limited (MOS FET with a high THD of 0.01% compared to the others if this really matters), and the B-209 which I use with the C-2301.

These were accumulated over a number of years when prices were lower driven by a desire to follow the evolution of Sansuis. I admit I am a jerk and all this may come off sounding pompous but believe me I am an idiot who had the money at the time , long hours at work with boredom requiring a hobby or quest, and persistence.

By the way, I also have an AU-111 G Vintage which does not sound special to me, I prefer the B-209 (designed for Sansui in the USA but assembled in Japan) and use it (the 111) as a headphone amp. And I am sure that you are wondering, yes, I did have a Japanese voltage AU-X1 that I listened to briefly before I sent it off to a former AK member/advertiser who is no longer in the forum . I would name him if he was still here. He stole it from me after leading me on for quite some time. It sounded great, quite powerful and seemed in full control of the speakers, but I doubt very much that it is/was better than the Alphas. More later. I haven’t had a chance to look at responses.

Marc
 
Continuing…

It’s kind of both sad and funny at the same time but I couldn’t remember whether I had the 907 NRA or not, I do, I had to look. It didn’t impress me at last listening. Not that it isn’t a great amp, ditto for the 907MR, but to me they didn’t stand out from the pack of Alphas. At this point it is not worth it to me to look things up but the MR was a great favorite of the Sansui employees who left the company when it was closing to found a new company in Japan (Aqua Labs?) which is now probably defunct. They were modifying it, as I recall, to come up with a solid state amp that recreated the legendary sound of the tube AU-111. This history was and probably is still available on the Best of Sansui site.

As I think I mentioned, the younger of my two sons has moved back in with me and is back in his bedroom where I have a lot of my Alphas, my B-209, and my Yamaha NS 1000 which I got because one, it is a great speaker and two, I can run my two Sansui tube amps with it. This room is pretty much unavailable to me now.

Downstairs I have Boston Acoustics VR-M90 speakers in the living room kitchen area with the Yamaha preamp and the B-2102. This combo was put in recently, I usually kept an integrated there and I think that I will end up with either a restored AU-919 or X911dg. I don’t think that sound quality will be much improved with an Alpha with what we listen to here (either FM or streamed music via an Apple Express through a DAC, CDs) and the sound quality either these amp/speaker combos are good enough for me and I am sentimentally attached to these two amplifiers.

In the guest room downstairs I have the Ren 90s. By the way, I have several switch boxes for A-B comparisons. I think that this is where I will make my final comparisons of the 07 Limited, Anniversary, 907 NRA, B/C 2105. At the rate I am going it may take me months to get there.

Cheers, and goodnight.

Marc
 
You have a very nice collection. And some tough choices to make. I liked but did not love the AU-a907NRA. I have yet to hear the renowned AU-a907MR (this is an amp a few experienced and respected members here consider to be their favorite Sansui). That AU-a907Limited could easily be an endgame amp too if you are wanting to keep it simple with just an integrated.

The C-2301/2302 are said to be the "best" preamps Sansui ever made. As well as the B-2301/2301L/2302 power amps. I can't recall his name, but there was a boisterous Greek guy here that had dealer involvement at that time and experience with all of the high end Sansui's. He said the 2301/2302 were the "best" separates Sansui ever made. Something to think about with that C-2301.
 
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I'd maintain that of the collection, the B-209 is probably the one I'd most recommend keeping. Since you seem to enjoy the sound of it (I know I do), that should be an easy decision to make. I'm a little surprised to hear you weren't overly impressed with the AU-111G. I've not had the opportunity to hear one, but I'd have thought it more noteworthy than you've described it.

I will say I haven't been overwhelmed by the Alphas I've heard. Objectively, they sounded very good. But they aren't really to my taste, which clearly favors "old school" Sansui quite heavily. My first move in Sansui was the 5000 receiver. All else that I've acquired (and kept) since then has been influenced by that being my first contact with the brand. I do very much enjoy their tube amps; AU-111, AU-70, Q-3535 and B-209 are all part of my collection.

I have a B-2301 (non-L) and other than the enormous headroom provided by it being a 300WPC amp, the signature if it's sound isn't head and shoulders above it's contemporaries (and I own an AU-G99X and two B-2101) by comparison. Maybe I lack the golden ear to truly appreciate the subtleties it can deliver, but that has been my honest finding.

And then there's the fact that I really enjoy a lot of the older, lower power amps immensely. BA-100 and 150 have become amongst my very favorites amongst the solid state gear I own, and I frequently find myself favoring them, or one of the numerous cap coupled receivers I own, for my primary listening setups.

My point in all of this is just to reinforce that one needn't feel obligated to hold onto the ultra high end rarities, if one finds themselves quite satisfied with gear of "lesser specs". For now, I keep mine, as I do enjoy changing things up with some regularity. But I can also understand wanting to thin the herd. The amount of gear I've collected has become something of a liability, much as I'm loathe to admit that. Mostly for the amount of space it consumes, in my case.
 
I'd maintain that of the collection, the B-209 is probably the one I'd most recommend keeping. Since you seem to enjoy the sound of it (I know I do), that should be an easy decision to make. I'm a little surprised to hear you weren't overly impressed with the AU-111G. I've not had the opportunity to hear one, but I'd have thought it more noteworthy than you've described it.

I will say I haven't been overwhelmed by the Alphas I've heard. Objectively, they sounded very good. But they aren't really to my taste, which clearly favors "old school" Sansui quite heavily. My first move in Sansui was the 5000 receiver. All else that I've acquired (and kept) since then has been influenced by that being my first contact with the brand. I do very much enjoy their tube amps; AU-111, AU-70, Q-3535 and B-209 are all part of my collection.

I have a B-2301 (non-L) and other than the enormous headroom provided by it being a 300WPC amp, the signature if it's sound isn't head and shoulders above it's contemporaries (and I own an AU-G99X and two B-2101) by comparison. Maybe I lack the golden ear to truly appreciate the subtleties it can deliver, but that has been my honest finding.

And then there's the fact that I really enjoy a lot of the older, lower power amps immensely. BA-100 and 150 have become amongst my very favorites amongst the solid state gear I own, and I frequently find myself favoring them, or one of the numerous cap coupled receivers I own, for my primary listening setups.

My point in all of this is just to reinforce that one needn't feel obligated to hold onto the ultra high end rarities, if one finds themselves quite satisfied with gear of "lesser specs". For now, I keep mine, as I do enjoy changing things up with some regularity. But I can also understand wanting to thin the herd. The amount of gear I've collected has become something of a liability, much as I'm loathe to admit that. Mostly for the amount of space it consumes, in my case.
He certainly has a fantastic collection of Sansui gear. I find that the alphas that I have all sound quite sophisticated and every bit the equal of modern versions by other manufacturers (for instance, the Yamaha A-S1200, the Luxman L-505/507 lines - which have gotten CRAZY expensive at north of $6000 just to get into the entry level model. (Haven’t heard the very modern Accuphases, so can’t say). The B/C2301 is the best combo I have heard. Period. But I have a Yamaha B-2x/C-2 in the offing soon, and these are serious pieces - so we will see.

BUT - there is something extremely right and enjoyable about the early 70’s offerings that makes me question why I would need more. For instance, the QRX-3000 (which is a damned near entry level quad from them) does things my alphas do not. And this is, maaaaaybe, 20 watts per channel (and direct coupled). Same goes for the AU-501, which is tiny power, old and capacitor coupled. And don’t get me started on the 9090. BTW, I also have a G99X, and I think it is the great sleeper of the line. A serious power supply pushing an alpha/x balanced circuit with the Sansui “digital” meters in a blackout cabinet. I don’t know - if I could only keep one of my Sansui’s this would be in the top 3.

I started this journey collecting Sansui. But I have fallen into some other brands as well along the way - and frankly I love some of them too.
 
@Plimpington2, sounds like you are pretty much in the same mindset I am at this point. I certainly recognize and acknowledge the alpha amps for the most excellent gear they are. They just don't quite suit my taste. Each time I've gotten a later Sansui amp (and 1986ish is the newest gear I own presently) as much as they impress me, I cannot escape my preference for the older gear, and it's unique sound. This is no knock against the Alpha era components, for those who prefer them instead. Just a subjective matter of taste.

Funny you mention the QRX-3000, I have one that has been languishing for years on the shelf with 2 blown channels and various other issues. When it last worked, it sounded good. Perhaps most notable is the odd things the all discrete (no IC logic) quad synth did on 2 channel material. It created rear channel effects than not even the QSD-1 has ever managed, although it was very hit or miss depending on the source material. I kept it mostly for spare parts use (quad gang pots) but it is still complete, so maybe I'll eventually repair it.

I try to relate my own experience and findings to others who pose questions like the OP has in this thread, for whatever they are worth (which is not much, really). But when someone like @mjs1 posts about wanting the thin their collection (which consists of some of the rarest and most sought after Sansui gear there is) and concentrate on just a few prized pieces, it's tough to make a solid suggestion. A good argument can be made in favor of keeping almost every model he listed, so it comes down to purely subjective criteria at that point. It'd be difficult for me to have to make a similar choice of what to divest, since everything I own now had it's own justification for purchase.
 
IMO a restored C2301 is the piece de resistance. restoring one is a big task afaik

And you have a B-209!! drool

So my updated choices would be

C2301 + B-209
AU-07 anniversary
something else either nostalgic to you, or if you had to see it every day you prefer the looks of it.

There's not a bad item in that list, any of that could be endgame

AU-111 as a headphone amp, lol

I might get a smaller SS like AU-222/555/505 for headphone use
 
I’ll might have some more comments later. Just three subjects now.

I agree that G99X is a great amplifier and a real bargain if you get one. It is a sleeper. I’m not a big fan of the display but you can turn it off. Going by memory now, and I may well be wrong, it was the second, X balanced amplifier available in the US market. The first was the AU-D11II. They also a good amount of power. I’ve had two but gave them to one of my two sons.

A short story about the B-2102 MOS. I bought on eBay. A very nice experience and got to briefly meet the seller. He was a former executive of Panasonic who brought in with him from Japan. He left Panasonic, as I recall, and went on to start his own company. Anyway, he was worried enough about shipping to personally drive it up to me from his home in New Jersey to Geneva,NY where I wss working. He was driving a Jaguar and threw in a Parasound preamp, which wasn’t part of the sale. We met at the Ramada in Geneva because it would be easy to find and had a few minutes of small talk. I offered to buy him lunch but he was in a hurry to get back home and he drove away after a handshake.

My current thinking is keep the B/C 2105 because they are among the last Sansuis and presumably peak MOS, the 907 NRA (not MOS but last TOL integrated), the 07 and Anniversary, the X911dg, 919, and 717, and if course the two tube amps (AU-111 G Vintage, B-208), and the C-2301.

That “Greek Guy” is JOMARK911 who is of course a fan of the X911dg and a big and early proponent of the
B-2301L. He hasn’t posted since December of 2025 and I hope he is alright.

Marc
 
It sounds as if you are hanging on to the prime picks of the lot then, a decision I certainly wouldn't argue against. That's still a pretty wide selection of excellent gear to choose from, but leaves you with the dilemma of how to use it all, if space is at a premium, and you don't want to be changing configurations on an ongoing basis.
 
The main part of my collection was in a second floor room that I no longer can use that has the Yamaha speakers so I don’t have good access to the B-209. I do have several switch boxes that I can use with the amplifiers. The X911 dg with perhaps another integrated (AU-919?) will drive the everyday listening Boston Acoustics in the kitchen/dining room area. I forgot to mention that in the TV room I have bookshelves Boston Acoustic VR-M60 speakers that are driven when we want to use them with the AU-9500. As a teenager I bought my first system which was a Dynaco solid state preamp and amp with Dynaco speakers. These speakers still sound pretty good to me and are in service in the living room (at weird angles dictated by space) driven in parallel by the amp that runs the VR-M90s. Anyway, the only speakers that I ever bought new were the Dynacos and the VR-M60. They were originally $1000 for the pair new and I’ve subsequently bought some on eBay used for as little as $250 for the pair. I think that these are fantastic speakers, especially for the price and if you are looking for a small bookshelf speakers.

Also on the second floor there is a stair landing that accommodates a desk. This is where I currently have the AU-111G, a turntable, airport express for streaming and a dac. This is only set up for headphones.

What I am currently thinking about is setting up is a system with a switch box in the rarely used office/ guest room where I have the Ren 90s. I have, among others, the so called “Sansui” switch box that was made by another company for Sansui and other manufacturers with an insert for the company name. I got mine restored, it needed a new transformer and was painted black to match the older Sansuis. I bought some remote controlled plug in outlets to go into a surge protector/power strip for the stepdown transformers and amplifiers. I plan on one turntable, tuner if I can get any reception down there (I live in a rural area with poor reception and my wife and I are against the esthetics of an outdoor antenna) and a digital feed through a dac via an airport express (what a shame that Apple discontinued this line. You can get reasonably good deals for the express and extreme on eBay.) A lot of my CDs are stored on a hard drive connected to an airport extreme which is on my home network, and I can stream all sorts of online radio stations and audio too. I have a big oak desk and think that I can keep one amp, the tuner, dac, airport, the turntable, and s switch boxes, and my computer on too, with the other components in home built two or three level shelves connected with remote power outlets and strips underneath. I’m thinking of putting the Alpha lineup there: B/C 2105, 907 NRA, 07 Anniversary, and the 907 Limited.

Marc
 
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