Borbely Superbuffers vs S&B TX102 - my impressions

[Sigurd Ruschkow]

I have had the privilige to have built and owned a preamp of
both the S&B TX102 volume attenuator transformers, and also Borbely's Superbuffers power by Borbely's power supplies.

I would like to share my and my wife's listening experiences that we have of both these preamps. My wife do not listen to music that often, but I listen almost every day.

To summarize:
Both me and my wife find that Borbely's Superbuffer1 sounds better than the S&B TX102 transformers. More detail, more slam, another octave of deep firm bass, and better focus and clarity on voices.

Sound comparisons
Both these preamps are of very high quality both regarding component choice, mechanical properties, and sonically. No doubt about that! Still, it was not that hard to hear that they did not sound the alike.

I built the TX102 preamp some months ago. The sonic character I hear is a smooth, bass-rich sound with great sound stage, a polished treble that is never hard or cold, and a body for each individual instrument (on good recordings) that can be very appealing. Details are OK. Transients could be better.

The preamp made up out of Borbelyäs designs has been online since a month and the SB1 is now fully burned-in. It sonic character is one full of details, resolution is higher than I ever had heard before, each instrument is clearly heard through a mass of instruments with a very good focus and body. The body I heard on the TX102 preamp is more muddy in comparison. Voices are better as they are easier to hear, more realesed, with better clarity. Soundstage is great with wonderful depth. Transients scaringly fast. Slam is fantastic. Bass is firm, powerful and deep. I did not know that my speaker could deiiver such a deep bass.


You can see both preamps in the 4 photos below.

The Borbely Preamp
I use the Superbuffer1 with Teflon PCB and Caddock high resolution MK132 resistors for the input, output, and feedback resistors. I also opted for the high output current option that is supposed to give better bass (and the SB1 can now also drive 600 Ohms, which I do not need). Instead of the voltage references, I have installed blue LEDs.

For power supply I used Borbely's 309 (unregulated DC with ultrafast rectifying diodes, Nichicon Gold Tune and WIMA caps) connected to the high-end 254 (actually a phono preamp power supply, which I bought as it has very low noise and can supply +- 200 mA) which gives regulated +- 24 VDC for the buffers. Transformers are 225 VA toroids from Amplimo that are potted, and shielded against both magnetic and electric fields.

The Borbely preamp is built up like dual mono from the AC outlet and onwards.
A mains net filter from Schaffner is also used for each channel.
For the stepped attenuator I use DALE's CMF55 non metallic resistors.

Silver wire is used for signal wires.
Standard gold plated chassie RCA connectors.

The S&B TX102 Preamp
The S&B is built in the same type of box with the same tupe of connectors and also the ELMA 04A2R00 rotary switch. Silver wire is used.



The TX102s preamp is sold, but the Borbely preamp will stay for a long time. Of course I have some mods to do like exchanging the RCA chassies connectos into WBT Next Gen Silver (they are just laying on my bench), and get some better resistors (Vishays probably) for the stepped attenuator,
and the SB2 will also be evalueted (it is supposed to have even higher resolution), and make a good looking box for each the power supply and the signal circuits (wood and Al with Teflon is planned).

Note: On the picture of the S&B preamp, you also see the Sowther volume transformers. These were so much inferior to the S&B102s that I will not mention them in this little review.

Note: The Borbely preamp box has both the Superbuffer1 and the Superbuffer2 installed. The SB2 has BG caps installed and the will be burned in sometimes around July, so I will not include the SB2.









Best regards,
Sigurd Ruschkowski

[pooge]

why not try the S&Bs with the active stage, i.e., replace the resistive attenuator with the S&Bs?

[Sigurd Ruschkow]

Well, maybe that would have been Nirvana,
but I do not think so.

Because the only input to the transformers was a low impedance CD player, and the power amplifier has 47k as input resistance, and that should be almost optimal working conditions for the transformers, and thus I do not think the TX102s will do much good in the Borbely preamp.





Sigurd

[Cobra2]

Please compare with BoSoZ (x-ed + ccs...)
Great information, by the way...

Arne K

[pooge]

Originally posted by Sigurd Ruschkow
Well, maybe that would have been Nirvana,
but I do not think so.

Because the only input to the transformers was a low impedance CD player, and the power amplifier has 47k as input resistance, and that should be almost optimal working conditions for the transformers, and thus I do not think the TX102s will do much good in the Borbely preamp.

Sigurd

Well I guess we won't know unless you try. You have the means available at your fingertips.

[tiroth]

He said he sold the TX102 preamp.

[analog_sa]

Sigurd

Many thanks for taking the trouble to write such a great review. My findings regarding the 102 compared to high quality active stages are very similar to yours. The problem is i find the 102 mk2 distortions attractive and addictive Of course for a purist they remain distortions.

[mikelm]

Sigurd,

Have you tried the mod in the TVC's to run them as auto transformers as detailed here

http://www.diyaudio.com/forums/showt...501#post601501

if you read through these posts for a few pages you get the details but basically you wire the P & S in parallel.

this mod gives more bass & treble detail.

For me this AVC mode is clearly better than the TVC mode

perhaps even a pure AVC will be better than this hybrid one

I would be interested for you to try this mode to see how much the transformer pre gets close to the superbuffer.

mike

ps I may have missed something but why do you have 4 transformers in you TVC pre ?

[Sigurd Ruschkow]

mikelm - no, I have not tried the auto transform wiring.
I do not have the TX102s anymore.

After reading the thread, I am not sure how much improvement one would have gotten in my system which has low output impedance and high input impedance.
Maybe some better bass.

The main disadvantages as lack of micro and macro detail, lack of slam (transients), muddiness compared to the preamp with Borbely stuff would probably still be there for the auto transformer wiring.


Sigurd

[Sigurd Ruschkow]

mikelm - the smaller transformers are the Sowther equivalent of TX102s.
Both are connected to the same stepped attenuator, but have different output RCA connectors. By moving the power amp interconnects between the two outputs I could easily compare the Sowthers and the TX102s.

More info in main post.


Sigurd

Originally posted by mikelm
Sigurd,

ps I may have missed something but why do you have 4 transformers in you TVC pre ?