Vinyl Asylum: REVIEW: Bent Audio TX103 MU Phono Preamp by Nasty

Model:	TX103 MU
Category:	Phono Preamp
Suggested Retail Price:	$825.00
Description:	Step up transformer
Manufacturer URL:	Bent Audio
Manufacturer URL:	Bent Audio

Review by Nasty ( A ) on June 24, 2006 at 16:40:47
IP Address: 207.6.193.235

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for the TX103 MU

John Chapman of Bent Audio arrived this morning with his box of goodies. We had selected in advance 3 album cuts that we would use for the listening session:

1. â€œNouveau Bachâ€ from the L.A. 4 album â€œJust Friendsâ€
2. â€œNo Frontiersâ€ the title cut from an album by Mary Black
3. Vivaldi Sinfonia in C, Helicon Ensemble on Reference Recordings

We chose each of the above for different reasons. The LA 4 cut has a lot of fine detail (bells, guitar, bass etc.) and the sound of the bells is especially telling in the highs. The bass of Ray Brown should have serious impact and texture. The Mary Black record is a real stinker. She has a very powerful voice but its hardness can drive you out of the room if not well reproduced. The Helicon Ensemble cut is interesting in that the strings are offset with harpsichord. The pounding rhythm of the harpsichord is the foundation of the piece and the violins can get a little screechy.

When John arrived we discussed briefly what we had in mind and got to work. My wife has an excellent ear and can spot problems quicker than I can. I like to work backwards as I am more sensitive to change as it gets worse rather than better (weird I know). The listening session would compare the Trichord Dino to the Bent Audio Copper and Silver Transformers. On Johnâ€™s demo sets he has a switch that can change gain from 1:10 to 1:20.

First things first; installation. The Bent units are larger than I expected. They are designed to sit behind the phono input but our shelf had no space for these units. The Bent transformers are designed with an integrated cable to connect to the phono stage and this is fairly short. Nevertheless, we managed to get everything to connect by placing the transformers 1 shelf below the preamp. John added a couple of ground connections and we fired up everything to check for hum. I cranked the volume to max and the system was virtually silent. The phono section being used is the twin triode MM stage of the Copland CTA301. We did a quick listen to determine gain settings and all agreed that the 1:10 was the way to go.

We started with the Bent Silver. The LA4 cut was incredibly smooth in the highs with the saxophone sounding exceptional. The bells sounded a bit odd..we are used to hearing a very clear bell sound but this made us question whether we had ever heard it correctly..it had a texture that reminded me of a brass bell rather than a silver bell..weird. The music was new to John but my wife and I both noticed a reduced bass impact. We moved on to the Mary Black cut. The vocal was probably as soft as we have ever heard it. The accordion came out from the background, nice. Once again the bass seemed to have taken a holiday. The Helicon Ensemble sounded a bit different also, strings sounded a little on the bright side and the harpsichord was a bit muted. The harpsichord carries the rhythm in this piece so the impact was pretty much lost. We discussed briefly what we had heard so far. We werenâ€™t disappointed with the Silver but it clearly was not a great match for the system.

On to the Bent Copper. The LA4 cut was much improved with the bell sounding more like we expect (â€œsilveryâ€). The saxophone had a nice rounded sound and the bass impact was a LOT better. Interestingly, the detail extraction seemed to be lower but the music held together better and was more involving. The Mary Black song was better also with an amazing clarity to all the instruments and her voice definitely not hard. Once again it presented a musical ensemble rather than a set of disconnected sounds. The Helicon Ensemble woke up for this performance also with a much more natural sound to the strings and the rhythm of the harpsichord driving the rest of the players. We were having such a good time that I thought we should add another test cut; Dire Straits Private Investigations UK 45 RPM disc. Well the house was shakinâ€™ pretty good and smiles all round on this one!

We then went back to the Trichord stage and played through 2 of the 3 test selections. Everyone noticed the bass on the LA4 cut. If the Trichord has a forte, this is it. The bass impact and extension are exceptional and it beat both the Bent Transformers in this regard. The Mary Black cut was a lot less musical than with the Bent Copper, the whole piece was less interesting and when the music got complex and mixed with Blackâ€™s strong voice, confusion reigned supreme. We didnâ€™t listen to the Vivaldi as we knew how this sounded from a playing the night before. Keep in mind that the Trichord was not exactly embarrassed by this test. It remains a good phono stage for most selections; we were deliberately working with difficult recordings.

John suggested going back to the Bent Copper transformer for another listen and we all agreed. We went straight for the Mary Black song again and confirmed our initial impressions. We talked to John a little bit about resistor loading on the Bent Copper. John had brought a supply of resistors with him for the listening session and we talked about adjusting the load to bring out more of the bass as we still felt it was a bit light. He added a 190 ohm (I may have this wrong so donâ€™t quote me) resistor to each and we played 2 of the 3 test cuts again (foregoing the Helicon Ensemble). The effect on the LA4 cut was as predicted with Ray Brownâ€™s bass work finally getting the spotlight when it was required. The Mary Black song improved also with the bass line more evident and the vocal more prominent than before. Interestingly, even though the vocal became the center of attention it never got hard.

As a final test we connected the Bent copper transformers to the Trichord phono stage to see if this configuration improved the high frequencies at all. The test was over very quickly as we all agreed that there was no advantage to this set up at all.

The entire session lasted nearly 3.5 hours and we felt that we had a good handle on the capabilities of the transformers. We talked to John about the â€œbuilt inâ€ cable that is part of the design. He agreed to build a set for us with jacks instead so that we could use our own cables as this would also allow a more sensible placement of the units. Once again we would like to thank John Chapman for making this all possible and for being extremely patient with us during the listening session. This opportunity is extremely rare in audio and we were very fortunate to be able to experience it. Oh yeah, in case I didnâ€™t mention it, we ordered a set of the â€œcoppersâ€.

Product Weakness: see text..bass shy but this can be improved with resistors
Product Strengths: exceptional clarity and musicality

Associated Equipment for this Review:
Amplifier:	Copland CTA 505
Preamplifier (or None if Integrated):	Copland CTA 301
Sources (CDP/Turntable):	LP12/OL advanced DC kit/Alphason HR100sMCS/Sumiko Celebration
Speakers:	Castle Winchester
Cables/Interconnects:	Cardas Hexlink Golden 5c (biwire)/Cardas Quadlink
Music Used (Genre/Selections):	See review
Time Period/Length of Audition:	3.5 hours
Type of Audition/Review:	Home Audition

Product Weakness:	see text..bass shy but this can be improved with resistors
Product Strengths:	exceptional clarity and musicality