What is remarkable about TX2575 in signal path(replacing Caddock MK132 and Caddock TF020/USF340, which had previously replaced Roederstein and generic carbon comp), is how much more detail & nuance of pitch & timbre TX2575 reveals across the entire spectrum, without sounding in any way thin or sterile. That said, these resistors eliminated bass slurring that some might consider warmth. There is also a blackness behind an airy, resolving yet smooth HF, that I want to believe is an attribute of a quieter resistor.
TX2575 is a lower noise version of TX2352. I have not yet compared the two types in the same application. The only commercial component I'm aware of the uses TX2575 is the Aria phono pre. That manufacturer offers it as an upgrade to TX2352.
I agree that AA is a more technical forum, but may be biased somewhat by budget-conscious perspective. It would be nice to have some manufacturers' opinions on these resistors. |
To obtain more power handling, TC offers the nude(unencased) TX2352 or TX2575 in duo- and triple-pack configurations. These are multiple resistors factory-soldered in series on a short foundation with one lead at each end. This is an expensive proposition, but it might be interesting to try some as an alternative to a good wire-wound resistor in a 1W or higher application.
One is curious who the hell it is who is deploying triple-pack naked Vishay resistors @$30?? |
The Russian NOS 6N8S I tried are rare & expensive mil spec stamped 1578 with metal base. I believe they date to 1955. |
Mr C,
Thanks for info on VSM-MX application; I have been on the fence about modding stock xover. I am considering Claritycap MR or Duelund for that job. BTW, TX2575 in signal path in BBAM increases transparency vs. stock MK132. Best to look inside Jadis and check values of resistors closest to phono input. Values are not always intuitive. They do make a difference. |
IME Riken carbon-film resistors obscure detail relative to Caddock MK132(warm but resolving) and nude TX2575(even more resolving, but without etch or coldness.) Nude TX2352 is identical to nude Vishay S102. The higher-spec nude TX2575 has no Vishay-brand equivalent.
With various mods & most recently TX2575, I'm trying to decide if transparency, clarity, and resolution are the ultimate goals of the sport & can be pursued in absolute terms without compromising other aspects of sound. With TX2575 the answer seems to be yes.
After the latest round of changes, I borrowed some nice NOS tubes, in order to compare the impact of resistor subs and other mods to tube rolling. Tubes included RCA 6SN7GT grey glass, Sylvania 6SN7WGT 1951, Raytheon 6SN7GT, and Russian 6SN7/1578/6N8S. My anecdotal conclusion is that in a well-designed component, no amount of tube rolling(at least 6SN7 rolling) definitively improves sound like TX2575. Moreover, assuming availability of high-quality tubes that don't blur detail, the shifts occuring with tube rolling are quite different in character(more subjective)than the across-board-improvement associated with rolling a high quality resistor. (My baseline for tube evaluation is current-production $12 6SN7EH, which gets surprisingly close to the best of the above NOS.) Some tubes (Sylvania & RCA) add obvious affectations and discontinuities, that while possibly compensating for shortcomings in some components, probably don't belong in neutral & transparent gear. |
I've ordered Duelund R to replace stock Caddock MP820/1 metal film in xover of Merlin VSM-MX, and will have results in 3-4 weeks. |
Mr. R: Thanks, I will have to try more NOS. Of the lot that I tried, I rank Russian 6N8S tops, followed closely by Raytheon GT, followed by EH. All three have top-to-bottom continuousness, good bass authority, big dynamic envelop, spaciousness, and detailed & refined treble. These NOS slightly surpass EH in nuance of pitch & timbre, increased palp factor & realism-- but not by much. Also, at $12 a pop for EH one can enjoy more frequent retubings--allowing enjoyment of tubes in the prime of their lifespan. A related point for consideration is where to obtain the most cost-effective improvement. So far, I'm inclined to to posit that a few hundred dollars in premium R is the better spend. At cost-no-object of course one wants it all. |
Mr. Y: You can order direct from manufacturer Texas Components or perhaps from Michael Percy (though I do not see them in his catalog.) I do not know about Audionote tantalum, except that someone I know with a good system said they were bass heavy & dark in his preamp. |
To address Kirkus's point that low-noise resistors make less difference in low-current locations, I just finished installing TX2575 at grid of amplifier tube in my phono preamp, and also at ingress of first gain stage to form standard 47K cartridge load. Both changes were very audible improvements.
Has anyone tried Duelund graphite resistors in crossover? The tweeter section of my stock crossover currently uses Caddock MP820/1 power resistors & Hovland cap. |
Mr. C,
I will email you directly regarding mods to BBAM. |
Clabe,
Hopefully you received my email; feel free to reply directly if you want more details. |
Hi Clabe, I ended up reworking the VSM-MX tweeter section in two steps. First, I replaced stock 6.0uf Hovland with 6.2uf Claritycap MR. (The two matched Claritycaps measured an actual 6.14uf.) Nice improvement--more openness and relaxation as compared to aggressive, forward sound of Hovland. After 150 hrs break-in of caps, I replaced 20R, 5.31R, and .8R Caddock MP820/1 with Duelund resistors in exact values. After 50 hrs break-in the initial brightness of Duelund resistors recedes & Duelund easily surpasses Caddock in clarity and refinement. Extraordinarily good resistors. Of the total improvement from these mods, I would credit Duelund R 60%, and Claritycap MR 40%.
To make room for Claritycap MR inboard requires grinding thickness off the MDF panel that supports the crossover network. I chose Claritycap MR over Duelund VSF mainly to obtain the low-resonance technology available in both of these caps, while also keeping the crossover inboard. To keep the crossover inboard with the large footprint of a Duelund cap in tweeter, would have required also installing Duelund in woofer(replacing 8uf and 8.5uf paralleled Hovlands with one 16.5uf Duelund.) While these two changes together would doubtless have sounded fantastic, I preferred feeling my way with an initial cap budget of $300, rather than roll over for $2K to Mr. Duelund. Maybe later on...
I find that bypassing the remaining paralleled Hovlands with a .015uf/200V NOS Russian FT-1 teflon cap slightly improves midrange and LF. After this all breaks in I will try a few more small teflon caps in parallel with Hovland in woofer section.
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Clabe, good to hear about your improvements. Prior to switching to fast recovery diodes in the Vel, I was always hunting around with the sub set-up and volume level. Afterwards everything just fell into place.
For a cheap and effective mod to SBAM, consider replacing the small .1uf polyester bypass caps around the op amps with ebay russian FT-1 .015uf teflon in parallel with .1uf K71 styrene. Clip off the steel leads and replace with good wire. Beyond that, the BAM benefits from upgrade to low-impedance, high-capacity SLA batteries. Few people understand that with an optimal power supply, op amps can sound as good as any tube or discrete SS device. |
Audiotweak, please post your findings regarding TX2575 vs. TX2352. |
Very interesting. It's been awhile since I made the comparison, but for me Caddock TF020 is a close second to TX2575. IIRC TF020 was initially strident on top, but eventually settled down. Nothing bland about TX2575-- just clean and clear. |
"The sound of the duelund cast were had very spotlight detailed, too much of a good thing, internet streaming showed certain tracks distortion very clearly."
I haven't tried Mundorf or Path, but Duelund R took my Merlin VSM Esotar tweeter to a level of clarity and refinement that has ended the search for resistors for crossovers. Definitely not too much of a good thing. No interest here in obscuring detail from any source. |
