I've been using Vishay Bulk Foils for a number of years, and have had excellent results. Supposedly wire-wounds are actually quieter, but there are other factors involved in the transparency of a resistor as well. Michael percy will match parts within 1% tolerance for you. (http://www.percyaudio.com/Catalog.pdf) A good person to do business with.
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I'm in the process of building a phono stage with TX2352 in the signal path. It'll be hard for me to say "ah ha" since I haven't heard it any other way, but everything I've read says bulk foils and nude Vishays are quieter. In my opinion, it makes sense to use them when dealing with small voltages like in a phono stage or preamp. I'm sure you've seen Michael Elliott's comments on the subject:
About Vishay resistors
When I asked for help to tweak my amps, most of the tube DIYers at Audio Asylum said Vishay's in the signal path would be overkill and/or sound sterile. They recommended carbon comps in that situation. FWIW, I don't know if these same folks would ever use bulk foils. They may approach things from a more budget-conscious perspective. It would be useful for me to try it both ways to find out for myself.
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.
Carbon composition resistors are some of the worst as far as noise. Here's a decent treatise on the subject: (http://www.aikenamps.com/ResistorNoise.htm) Note what he says about wire-wounds and inductance. As you mentioned Mr D: The carbon comps DO add colorations that some find appealing. That's generally what I found on the AA forums- Lots of folks with lots of opinions/tastes, but very few that compared what they were hearing with actual music. I believe there are more individuals in here that are familiar with live music, and seek to capture those flavors at home, or(at least) do as little harm to the signal from their recordings as possible.
Rodman, thanks for the link to Aiken Amps. That was an excellent tech note! There's a slew of other fine reading where that came from:
I'm placing an order for some TX2575 today.
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??
Another vote for "naked" Vishay resistors. It is amazing how they transformed my Counterpoint NP100 power amp.
I first got a Counterpoint SA100 as my 2nd system. It was quite musical. But it ran too warm, and it sounded better the warmer it got, by adjusting the biases. Then I upgraded it to NP100 Basic. It ran much cooler and sounded a bit better.
Then I upgraded it to NP100 Basic Gold. It sounded real nice then. So I moved it to my main system and moved my KT88 monoblocks to the 2nd system. I thought it was good enough until a friend brought his NP100 Premium Gold to my house. The NP100 Premium Gold has "naked" Vishay resistors in the critical signal path. Within 30 seconds after switching to his NP100 Premium Gold, I knew that I had to upgrade my amp.
Instead of upgrading to the same level, I chose to upgrade my amp to the top level, NP100 Platinum, which uses "naked" Vishay everywhere. It was a very expensive upgrade. But the results are amazing!!
I think I am set with my power amp, after the "naked" Vishay upgrade. Now my NP100 Platinum drives my JMlab Alto Utopia with authority and yet is so refined like a SET amp.
I'm a newbee when it comes to circuit tweaking, but I recognize the importance of low noise resistors in critical positions like input stages. As I said above, the folks at Audio Asylum steered me toward carbon comps. I took their advice and used them in a position that connects the coupling caps of my amp's input stage to the power stage. This is obviously in the signal path. For those that like details, here's the circuit diagram and resistors in question: R18, R19, R20, R21.
After reading the article: Resistor Types - Does It Matter?, and hearing what others have said, I realize these are the worst possible resistors I could be using... especially with a 1/2 watt power rating.
The article states:
Contact noise is dependent on both average DC current and resistor material/size. The most significant contributor to noise in guitar amplifiers is the use of low-wattage carbon composition resistors. Since the noise is proportional to resistor size, the use of 2W carbon comp resistors will improve the performance over that of 1/2W resistors. Studies have shown a factor of 3 difference between a 1/2W and a 2W carbon comp resistor operating at the same conditions.Another interesting quote:
Wirewound resistors are the quietest, having only thermal noise, followed by metal film, metal oxide, carbon film, and lastly, carbon composition.So I want to replace the carbon comps. My question is whether TX2575 or TX2352 are overkill for this situation. They aren't cheap at $10 and $7 a piece. I need a total of eight. Would Mills MRA-5 wirewound be a decent option? They're less than half the cost.
Noise from resistors is based on the amount of current flowing through them, and there's virtually none flowing through R18, R19, R20, and R21, especially at audio frequencies. These are "grid-stoppers", whose purpose is to create a high-frequency pole in the amplifier's open-loop response, in conjunction with the output tubes' grid (Miller) capacitance. Don't worry about these.
If your want to swap some resistors, I'd start with R2 - the voltage that is amplified by every other stage begins as a current through this resistor. Second would be R12, then R3 and R4, as this makes up the feedback ladder. If you change R12, you might put a high-quality polystyrene cap for C4.
For plate-load resistors like R2, you should keep an eye on resistor voltage ratings as well. IIRC, the Vishay S102 is rated at 300V, so if the 'naked' derivitives are rated the same, you should be fine here.
Many thanks Kirkus. I appreciate you taking the time to look at the schematic and offer such a thoughtful reply.
I have PRP's in the positions you mention. In your opinion, would it be worth swapping in low noise resistors or will the benefit be marginal? It's probably hard to know the results for sure, but thought I'd ask anyway. I'm willing to upgrade if it offers an improvement, but don't want to throw money at the situation when it doesn't do anything.
my opinion changing resistor doesn't make significant difference such we change tube or capacitor ,although they still have difference sonic character ,another good resistor that i recommend is Riken RMG ,i was ever been compare with vishay S102,the riken have better midrange reproduction & warmer sound than 102 ,but 102 have better tranparancy & clarity.i have never been compare to TX2575 yet
Mr Y- Any components(passive or active) that can be replaced in the signal path(or power supply) to provide a more transparent conduit (and gain) for the signal will have a cumulative effect. Many of us desire to provide as transparent a path, from the source to the speakers, for our music as possible. That entails replacing anything that adds or subtracts from the original signal. Some components(generally utilized in manufacture for the sake of economy) are known to induce noise, warmth or other colorations, and are targeted for elimination. What may seem insignificant or desirable to some, is found unacceptable to others.
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.
Mr D- The tubes that you auditioned(all but the Russian, which I never tried), all brought artificial warmth to my system when used as phase splitters or drivers in my Cary monoblocks. Trust me when I say that if you had tried a NOS pair of TungSol JAN CTL/6SN7GT round plates(40's), or Sylvania JAN CHS/6SN7W, tall bottles- your idea that tube rolling won't provide an across-the-board improvement like a resistor change is flawed. The improvements in transparency, sound stage(width and depth), dynamics, focus, frequency extension(both directions, without glare or bloat) and imaging that these tubes provide when compared to other 6SN7's is amazing(not quite as dramatic when compared to the Sylvania and Ken-Rad bottom gettered VT-231's, which are also excellent). They further allow the proper harmonic "bloom" that accompanies live instruments(without any excess) and accurate transient attack and decay. I can't live without them! Of course the resistor change provides improvements in transparency regardless of the tubes installed(so we're comparing apples and oranges here), and whether one likes an accurate, transparent presentation of what's on their recorded material or prefers the kinds of colorations some enjoy makes any comparison "subjective". Personally- I want my system to provide the qualities that I hear when I'm working as a sound technician, attending a live concert, or playing my guitar. Hearing live music 2 or 3 times a week for the past couple decades has given me a pretty good idea of what the real thing sounds like, and I can't abide noise/warmth/sibilance/sugary glaze or anything else that doesn't exist at a properly set up live venue. That there are others that want their systems to sound that way doesn't surprise me at all, or affect my tastes in the least. Enjoy your music, and the quest!
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.
I don't think Michael Percy sells TX resistors. I asked recently and he said no.
You can buy direct from the manufacturer:
It's a small company with helpful and friendly staff that actually answer the phone. It's a pleasure doing business with them.
The top vishays are the S102 and the VSR.
They are measureably quieter than anything else out there, and have an openness to the sound. If you install Vishays and your piece now sounds bright, the brightness is due to something else; not the vishays.
I have been using Vishay bulk foil for over 12 years. They make a huge sonic improvement in any piece I Have installed them in.
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.
I´ve changed to Duelund (big ones) graphite resistor and Mundorf Silver/Oil cap on my Merlin MX in tweeter section.
Sound is smoother but yet detailed. Hovland I find edgy/harsch. I would very much like to swap the whole crossover to Duelund caps/resistors, but it would break my budget.
I would like to change input resistors (47k) on my Jadis DPMC phono pre. Don´t know if 47k loading is of one or more resistors, no circuit diagram. It´s just to test, maybe it´s not worth it. I use MC cartridge of 0.6 mV.
Thanks and enjoy music!
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.
I ordered my Starsound amps 5yrs ago with the naked Vishay resistors. The upgrade in price was well worth the increase in resolution and reduction in noise floor compared to the same amp with the standard resistor pack. Part of my decision for the nude was based on my previous upgrade to Vishay bulk metal film resistors configured in a bridge mode to replace those that were stock in my Dunlavy SC4's. That was a shocking difference to both my pocket book and to my ears. Well worth the expense. Tom
Today I replaced one resistor in my Starsound amps. I swapped out the parasitic resistor tied to the small air core inductor that goes to a speaker output. The resistors that were in there were North Creek/Ohmite non inductive wire wounds considered one of the very best of this type and for this application. I replaced this resistor with the same value and wattage Duelund. The difference was apparent with one amp playing while hooking up the other. In my office now listening to music from the other room the sound is much more life like and resolute even at moderate levels. More punch more extension detail and transparency. I thought there would be a subtle difference that would carry thru further when I revise my speaker crossovers and their four resistor values..Lets see 4 times the difference I am hearing now with the subsitution of just one would make for a huge difference. I'm glad I already have the Duelund replacements on the way. Again as a replacement for the North Creek/Ohmites in my speakers. Tom
"Of the lot that I tried, I rank Russian 6N8S tops, followed closely by Raytheon GT, followed by EH. "
Is it common consensus in audigon?
I've read from some other forums that Russian made 6N8S tubes are not as good as US made 6SN7 family tubes.
This link may help further understand 6SN7.
Yes I as well have used Vishay S102's many years ago and ran an ear opening experiment with them. I had an Adcom 535 Amp. De soldered one entire channel only with about 13 Vishays Bulk Metal Films. The ones that cost about $10.00 Each. I did this just for one channel only to see if I could hear the difference, and let the other channel alone.
All I can say was WOW WOW WOW.The noise floor dropped way way down. You coud hear absolute silence between every note that was played thru my phono stage. Detail was magnified substantially But without any hardness to speak of. Everything was absolutely effortlessly in reproduction. Once I installed the ther channel the 3D imaging really expanded wall to wall. To bad I still do not have that amp today. It was one of a kind and alot of work, But worth the challenge. I hope this answers some of your questions.
Good for you! I did the same thing with Vishays bridged in speakers and the difference was shocking. The image is wall to wall. I think the Duelunds that I recently purchased have a simliar impact as the Vishays. The Duelunds are a easier and less expensive swap than building a high power resistor out of many Vishays for speakers and in some instances power amps. Tom
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.
Nice to hear improvement on tweeter section by changing to Clarity/Duelund. I use Clarity and Mundorf silver/oil in my phonostage (se humblehomemade test). Nice relaxed sound.
I just ordered som Vishay Foil TX2352 0.1 % at TEXAS Components. Really nice people to deal with, I expect to get them before Christmas. I will use them in input stage of phono and SBAM, also change to Mundorf Silver/Oil in SBAM.
BTW, Thanks for advice on changing to FRED diodes in Velodyne sub. I did on my DD10 and it certainly improved speed, more distinct and improvement on overtones.
Another very velcoming improvement was increased sensitivity on lover volumes for triggering the sub.
Now I can listen with sub at lower volumes than previously.
To shear experience and help others in a forum thats worlwide, that´s what it´s all about.
Merry Christmas & Happy New Year!
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.
Vishay TX2575 are made from the new Z foil that was developed in Israel. They are suppose to be even lower noise yet. They cost $9.40 each. I have them on order for my Altmann/ DD Dac combo hybrid which is currently using the standard Vishay metal film nudes. Throw another $60.00 at this and hear what differences there may be. Tom
I'm bumping up this thread as I just completed a comparison of resistors in the gridleak position of a tube pre-amp.
Holco (old stock)
Caddock USF340 (TF020)
Generic Metal Film
This was quite an interesting undertaking as I was not expecting to hear drastic differences. In the past I heard differences between resistors but mainly in the high frequencies (cartridge loading application)
The Shinko Tantalum was by far the most inaccurate resistor of the lot. Dale RN had the most bass and midrange warmth. TX 2575- the biggest disappointment of the lot. A laid back/bland/lifeless sound. S102/PRP/Takman/- not worth the time of day. Holco- now this is an interesting part. Very lively/dynamic/textured presentation with great inner detail and prat. Unfortunately it adds a fullness to vocals and mid-bass that ultimately becomes distracting.
And the winner......by a w-i-d-e margin is the Caddock USF340 (TF020). Clearly the most transparent/musical/involving resistor I've had the pleasure to hear.