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Posted by Paul S on
03-11-2007
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Not to go overboard after only 2 days of operation, but the Bent TAP (transformer-attenuator [passive] pre-amp) is a pip in my system. It is as "neutral" as anything I am familiar with, compared to by-pass (with CD). I love having a useable remote [for the first time]! The TAP "passes" bass very well, indeed, and it allows the pitch, timbre, weight and scale of well-recorded music full play, along with excellent "timing", from an orchestra ramping up to a mere gesture of a glissando. It not only handles all frequencies and volume settings in my system but it "allows the personality and intent" of performers to come through (how's that for a reach?). Basically there is not much to say because I feel very strongly that I am "listening through" the TAP to everything else in the system.
The Bent drives just 6 feet of IC to the ML2s in my system, but it does so without a hitch. It does have an automatic, "inaudible" 6 dB gain once "unity gain" is selected/arrived at, although I will not need/use this (transformered) boost in my present system.
It has all kinds of nice features, including a mute, balance, phase option, and ground configuration options.
This unit is ABSOLUTELY SILENT in my system.
bentaudio.com
Best regards,
Paul S
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Posted by Romy the Cat on
03-12-2007
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I do not know what LF you have but, I would be very interesting how this unit will behave in context of a playback with fully developed LF as all of transformer-attenuators should kill bass. Anyhow, I will subdue any my typical criticisms about the transformer-attenuators and would juts note that all companies the make transformer-attenuators “forgot” to mention that this thing is highly depending from…. everything. It has variable output impedance not only from a given volume setting but from output impedance of a given sources. Nevertheless, it looks like after the years of playing with that B&S transformer Bent Audio eventually shaped it in product. It dos not look expensive, it looks “comfy” and if it sound as you said transparent enoght then… Good for them…
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Posted by Paul S on
03-12-2007
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I also got tired of reading all the DIY posts on the S&B 102. And yes, I have done the numbers, and it would be possible to adversly affect bass with high impedance feeds and/or long, bad cables feeding this unit, coupled to a low impedance load/amp. But my own set-up is pretty much the opposite, with short cables and low-impedance (200 Ohm) feeds and 41K input for the ML2s. Ironically, this unit "acts as if" it is buffered in my system.
Who knows how these do under 35 Hz or so, really, not I, but they simply kick ass to/above that point, with no let up. On the Sheffield D-to-D Leinsdorf "Valkerie" (yeah, yeah, I know...) the bass is simply overwhelming, and no compression whatsoever at any volume I would care for.
Of course, I continue to evaluate my gear indefinitely, and I am still the same whore I always was.
BTW, this Bent guy, John Chapman, also makes a total Vishay R-based unit, for those who either want to save some $ or who might not be able to use the trannies, for whatever reason.
I have not tried the Placette active, but all other R units muffle/kill pretty much everything, hence my gambit into TVC, and so far, so good.
Best regards,
Paul S
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Posted by Romy the Cat on
03-12-2007
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Well, if you do not have anything user 35Hz and have low sensitivety then the passive might do. Still in future, when you feel comfortable with your passive unit you might for the sake of self-education try an following experiment: Guy Hummel use to have an separate buffer in a small box and a set of very short cables. He used to lend the set for free to the passive preamp people to let them experience what a real good buffer can do when it plugged right after a passive unit. Despite your 35Hz I think that you might find it beneficial. His active buffers are way more capable Hummel's own or Chapman's passive units. I do not know about the transformer units. Still, I do not see any needs to have a transformer (with it's all probelms) juts for a sake of attenuation. If you try the Guy’s active buffer after the Bent's unit then let me know – it might be interesting to learn.
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Posted by Paul S on
03-13-2007
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Like I said, musical bass via the TAP does not thin out at all before my BR bins roll it off; but that's as much as I can say at this point. And (against conventional logic) the TAP certainly does much better bass than any active LS I am familiar with.
Have you actually tried the Bent TAP with (or without) this buffer? Regardless, putting that buffer on the TAP would be just the sort of experiment I like to try for myself. How do I get a hold of this "buffer", and what, other than another active circuit/stage, does it "add"? I read that the Placette Active creates an effect such that it "presents a constant [18kR] load" to sources; but the heart of the "active" Placette is, of course, still passive (resistors in series), and it has to present a variable (series) resistance path to a signal to do its job, right? Always worth a go on the strength of your recommendation, i'm sure, but passive R presents its own problems, as any variable form of attenuation will, and adding another active buffer stage probably does more for the cables than it does for the signal. Regardless, I have planned for some time to try both the Placette Active and the Bent TAP at some point, just because they both interest me; I just happend to start with the TAP, and in my system the TAP is definitely worth integrating compared to and instead of any active unit I have used/heard to date. And now that I've tried the TAP, and based on your negative predisposition, you might be surprised, given fair consideration to input and output loads, of course.
Meanwhile, and despite myself, I am a too often a critical listener, so I am sure I will sooner or later discover the TAP's weaknesses.
PS: Want pain? Try Vishay 102s for grid resistors!
Best regards,
Paul S
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Posted by Romy the Cat on
03-13-2007
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Yes, you are right it is rather my negative prejudges and I should not proud about it. It perfectly possible that Bend is a fine performer…. Still, it is a transformer and no mater what you do is a band-pass filter. It is still inductance at the bottom and capacitance at top. It is still not pure respective load despite that actually all that be need it to have a regular voltage divider as the function of this thing is juts to attenuate. (in fact a whole active stage of buffer also ridicules from purity perspective).
Do not get me wrong I do not question to Bent performance but I learned that over my years that as soon I see people claim an “absolute transparency for passive preamps” then I eventually recognize people with bookshelf speakers.
Regardless, any other considerations (constant impedance, bass, HF, granularity override and many other) there is one that were I feel an good active is more interesting then any passive: dynamics. From what I have seen the Hummel’s buffer supersede a dynamics of “straight wire” and it made me “converted”. I do not really “promote” Guy’s here but I rather promote the idea and since it is free to try I think it might be beneficial to try.
I have to admit I did see in my life a transformer that overage and increase dynamics of “straight wire”. It was not the B&S transformer and it was a different application. In fact the B&S transformer in the very same application did very fine job but DID NOT increased dynamics. If THIS line-level B&S transformer does the “straight wire decompression tricks” then it is very good. If not then it should be looks further. Eventually you will be the one who judge…..
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Posted by Paul S on
03-13-2007
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Sorry, I should have said by now that my (15" Audax PR380M) bass units are FLAT to 38 Hz, and then they roll off naturally at 24 dB below that, meaning if I have 38 Hz @ 100 dB, then ~30 Hz is still >88 dB, and obviously 20 Hz is still plenty "audible". And, yes, the point of attenuation is exactly/only to scrub and shunt unwanted voltage, which task the Bent obviously (from sonic results) handles with aplomb. It is not just "quiet"; it is truly noiseless.
I did not mention it, since I also changed my phono stage, but re-thinking it, it is also true of CD, so here goes: The Bent "removes the back and side walls behind/around my gear", which I sheepishly admit I just love. But then, I had also noticed this effect with bypassed CD playback with the same music. I would have to spend more time going back and forth between the Bent and bypassed (CD) music to get a better handle on any long-term differences. But several hours at it did not turn up anything, and in any case the end results are not only satisfactory they are stunning. I never dreamed (OK, I did "dream" it; that's how it came to be...) I could get this kind of clarity without that annoying active upping-of-frequency and lower treble granulation that is the staple of all the "audiophile" active stuff. In this case the bass is just ferrocious, and you know I've had to work my ass off to get this kind of bass with OB, so there's nothing "extra" down there coming from my speakers, that's for sure.
Maybe I should also say that I happen to very much prefer my MC cartridge initial gain to come from a step-up transformer, versus an active hi-gain stage. But I really do not hear at all from the TAP any "transformer function" sound that remotely smacks of "transformer gain", especially since I am pushing 100 dB +/- at a volume setting of "22" and the "unity gain"/6 dB "boost" function does not kick in until "31", and then it just turns around and scrubs it off, anyway, just to keep the lines "loaded", so the "gain effect" is in any case not detectable as any sort of boost, or so they say.
As for dynamics, there is simply no contest between the Bent and my very tweaked AI active LS. I suspect that anyone who has a "dynamics problem" with the Bent has a dynamics problem. You hear plenty of live music, and so do I. The Bent lets a performer do his/her thing, according to the source, and I repeat that the Sheffield "Valkerie" via the Bent would make the average audiophile piss his pants. This is a real "bonus" for me, since I did not set out on this partiocular project planning to feature this sort of music, for obvious reasons. Now, however, my greed is unbounded, and I look forward to the EMI Callas/La Scala/Tosca this weekend, "dry" surfaces notwithstanding!
And I think I already mentioned that the "Valkerie" I cite is Leinsdorf (albeit LA), so you know what that means in terms of bass.
Best regards,
Paul S
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Posted by Romy the Cat on
03-13-2007
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Well, Paul the more you happy and pleased with your transformer-attenuator the more I feel it would be interesting to see your reaction to a good active unit. A “good unit” should be the key-world in here as since you complained about active units’ noise and active unit’s lack of dynamics then I presume that you never trued any good active preamp. Sure, I might be wrong, since you did not detects any differences in bypass test. However, since you use a passive preamp then you need to do perform the bypass test WITH EACH OF YOUR SOURCE.
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Posted by Paul S on
03-13-2007
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Please do not get the idea that I ever "ruled out" active pre-amps or came to the TAP through some sort of object worship. I really couldn't care less about how the job gets done. Active is fine, as long as the results are there. I am NOT a "passive guy", and I do not "look to passive" for answers. In fact, I never thought long or seriously about passive attenuation in lieu of a "normal pre-amp" until you started crowing about the Placette. Since I certainly do not need another gain stage (and since the Placette "active" I was bidding on went to someone else), I gave the TAP a try. What the Hell? It's YOUR fault!
Obviously there must be some sort of "losses" involved in an attenuation device, if only because that's pretty much the nature of the beast. I want to hear for myself the differences between the passive unit(s) and the active (gain-type) pre-amps I've struggled with for so long.
Of course, you may be referring to the Placette as "active", but, again, the beating heart of that unit is passive.
You have futzed around with buffer stages. I have no serious experience with a plain old buffer stage, mainly because I have always paid attention to cables and kept my cable runs short, and I never "felt the need". I never thought about or tried a buffer "just to do it" because, I suppose, it just seemed like one more thing to go wrong. That old pre-supposition again. But if you say they smoke, I'll stick one in there at some point.
This logic is faulty, especially in audio, I know, and the proof is the "extra" gear required to boost a LO MC with a transformer. Makes no "sense", does it?
Active; passive; Class D: bring it on.
Best regards,
Paul S
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Posted by Romy the Cat on
03-13-2007
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Well, I do not know what this conversation is all about. Anyhow, one point I would like to make – try to plug it into the context of the thread. It is very simple to run Sheffield’s Leinsdorf "Valkerie" and to “like” bass and dynamics. The REAL really is different. The real dynamic capacity of a passive preamps couldn’t be observed on the Sheffield blockbusters but in more complicated things. A low volume, low dynamic lever, a lot of ambiance and… here is where you need as much bass and as much dynamic as you can get. Listen for masking of rhythms and for the amplitude of pronunciations. The accent of beat, the little punch-line where it is appropriate - here is where the real dynamics at works. Try to “get dynamics” in Shostakovich quarters instead of the Mahler symphonies. Well, I do not know what this conversation is all about. Anyhow, one point I would like to make – try to plug it into the context of the thread. It is very simple to run Sheffield’s Leinsdorf "Valkerie" and to “like” bass and dynamics. The REAL really is different. The real dynamic capacity of a passive preamps couldn’t be observed on the Sheffield blockbusters but in more complicated things. A low volume, low dynamic lever, a lot of ambiance and… here is where you need as much bass and as much dynamic as you can get. Listen for masking of rhythms and for the amplitude of pronunciations. The accent of beat, the little punch-line where it is appropriate - here is where the real dynamics at works. Try to “get dynamics” in Shostakovich quarters instead of the Mahler symphonies. It would be more demanding…
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Posted by Paul S on
03-13-2007
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Yes, of course, agreed and point taken. I am/will be conscious (at times) of all those things as I listen, and I remain a musical omnivore. I am pleased, though, as I mentioned, because this is the first time I have had such success with this well-known blockbuster, and I had pretty much given up on this stuff a while back. So far, there is no indication that the (bonus) big stuff comes at the expense of the gesture; quite the contrary. But I still have some work to do to isolate the phono stage from the TAP in terms of my impressions of LPs, at least as far as this particular thread is concerned.
Best regards,
Paul S
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Posted by George on
03-14-2007
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I have had a Placette Active for some 5 years now and it was quite a revelation when I put it in my system. According to Guy Hamel one of its most important features is its powerful op-amp output stage with an output impedance of 10 ohms. Since I have to drive 8 meters of RCA cable this was of high importance to me.
Recently I had a brainstorm (very small) and bounced it off Guy (who is a terrific person to talk to) and he thought it would be worth trying. Since I was driving such a relatively long length of RCA cable (thus subject to noise pickup) I thought why not run the Active with no attenuation (full strength signal) and put a passive Placette right next to each amp. Actually I bought RCA male/male couplers and plugged the Placette right into the amp.
Note that I have inverted the usual order of attenuation then output to output then attenuation. Guy told me this has no disadvantages and should in my case increase the signal/noise ratio. This also allows the the sources to see the constant impedance of the Active and allows the strong outputting Active to drive the Passives which don't have to drive very much at all.
To me there was a worthwhile improvement which may or may not be due to the
theories stated above and which may only apply because of my 8m of cable.
This is somewhat like what Romy is talking about with a voltage divider but since I have no DIY skills I need to use plug and play components.
If I had known of this setup originally I could have bought an active output unit without the volume control stage from Guy and then simply added two passives at not too much more than the standard Active. If I still like this setup after 6 months I will probably sell my Active and replace it as stated just to simplify things.
Note: the passives operate with their own remote and the Active can be set up to operate on a different remote so that its volume setting is not affected by the passive's remote.
Any comments or criticisms are welcome.
George
PS From the Lamm website I just saw this instruction about the 2.1:
NOTE: 6N6P tube should be replaced every year
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Posted by George on
03-14-2007
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Romy,
I have always been meaning to ask you why a step-up transformer for a cartridge can be acceptable but a transformer elsewhere is considered detrimental.
Thanks,
George
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Posted by Romy the Cat on
03-14-2007
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 George wrote: | | Recently I had a brainstorm (very small) and bounced it off Guy (who is a terrific person to talk to) and he thought it would be worth trying. Since I was driving such a relatively long length of RCA cable (thus subject to noise pickup) I thought why not run the Active with no attenuation (full strength signal) and put a passive Placette right next to each amp. Actually I bought RCA male/male couplers and plugged the Placette right into the amp. |
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Well, the Placette active does not really cares if you have any attenuation before it as it runs I’m sure, in class A1 and full-opened anyhow. The only reasons why it “might be” useful to put attenuation it the power amp input is to implement current loading of that 8 meters interconnect. Some cable (most all of them) response to current loading very positively. This all should lead Guy to think in the direction that he should make power amp input kits. This kit might have a pair of his passive attenuators and a common for both channel IR detector and switching processor. You see, George, in what you propose I see a problem. Sine you have 8 meters interconnects I presume that it a relatively large room with speakers positioned relatively far. This way your common remote control will drive two Placette passive units located a few meter away. I think it is perfectly possible (since it is it IR control) that one of the sensors will not pick the signal right the way and you have unintentional balance between the channels set off….so, they both should be driven form a common sensor…. That will make to run another 2 x 8 meters cables… sure it is all accomplishable…. How much are you wiling to pay… just to try? :-)
| George wrote: | | Note that I have inverted the usual order of attenuation then output to output then attenuation. Guy told me this has no disadvantages and should in my case increase the signal/noise ratio. This also allows the the sources to see the constant impedance of the Active and allows the strong outputting Active to drive the Passives which don't have to drive very much at all. |
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Actually I very much disagree with you and with Guy on it. if you have buffer and then, right after it the attenuator, then it defeats all purpose, from my point of view.
| George wrote: | | If I had known of this setup originally I could have bought an active output unit without the volume control stage from Guy and then simply added two passives at not too much more than the standard Active. If I still like this setup after 6 months I will probably sell my Active and replace it as stated just to simplify things. |
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There are some disadvantages in what you propose. However, you do not use multi-amping, have the ONLY one source and have the ONLY one amp then it might be OK. Still, to my ears, even with 1M cable the Placette active sound better then Placette passive. The Placette passive has that “sleepy sound” that all passive preamps do… A few years ago I took 3 meter cable, drove it from BiDat (direct coupled with 38R output impedance) and begin to slice the cable, soldering the very same 3 db voltage divider at the begins on the cable AND then at different locations of the cable length. The result was absolutely unambiguous: each single inch of cable AFTER THE DIVIDER made Sound more and more inept… Rgs,
Romy the CaT
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Posted by Romy the Cat on
03-14-2007
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| George wrote: | | I have always been meaning to ask you why a step-up transformer for a cartridge can be acceptable but a transformer elsewhere is considered detrimental. |
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I do not say that step-up transformer is good but the transformers elsewhere are bad – I have no knowledge or credentials even for myself to make those statements. However, from my restricted perspective I see in step-up transformer and in the transformer-attenuator very different purposes. A step-up transformer has a purpose of “transformation” or increase voltage and it could be done in case of MC cartridges only by a transformer or by an active stage. A transformer-attenuator of course also “transforms” one voltage into another voltage but it is till around the very same attenuated voltage and therefore the transformer acts juts as a fancy voltage divider. Sure, there is nothing wrong with a transformer-attenuator if it has a pure restive load but as we know it is never the case. If we need a drop voltage elsewhere then we use resistors, right? We do not we use transformer-attenuators everywhere else instead resistors. Why then we need suddenly it use a transformer-attenuator as a volume control?
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Posted by George on
03-14-2007
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| Romy wrote: | | I see a problem. Sine you have 8 meters interconnects I presume that it a relatively large room with speakers positioned relatively far. This way your common remote control will drive two Placette passive units located a few meter away. I think it is perfectly possible (since it is it IR control) that one of the sensors will not pick the signal right the way and you have unintentional balance between the channels set off….so, they both should be driven form a common sensor…. |
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The remote is not a problem. Using a Xantech distributer, repeaters, and electric eye you can configure the two passive remotes in a foolproof, or nearly foolpoof, manner for about $75-100 total. Since I already had the basic Xantech gear the additional cost was some $15. The problem is that if you have the Placette exposed to both Xantech control and and direct line of sight from the remote the Placette will receive signals from two sources. However, Xantech makes an IR cover for just this purpose for $3 that prevents the Placette from receiving direct commands from the remote. So far I have not observed any difference in the level settings of the two passives when hooked up in this manner.
| Romy wrote: | | However, you do not use multi-amping, have the ONLY one source and have the ONLY one amp then it might be OK. |
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Multiple sources is not a problem as the replacement unit would be just like a full active Placette but without any volume control. An active switchbox, if you will.
| Romy wrote: | | The result was absolutely unambiguous: each single inch of cable AFTER THE DIVIDER made Sound more and more inept… |
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A valuable observation and something I was concerned about. I have tried to minimize it by plugging the passive directly into the amp but this must take its toll. Guy thought this was overkill and insisted the passive can drive several feet of cable without loss..........but what does he know. <:-)
I based this experiment on the assumption that the stronger the signal from preamp to amp the better the signal to noise ratio. I am getting the impression that this may be of minor importance. Anyway it will take me several months (I am a slow listener) to understand this change and if it really is an improvement.
Anyway, Romy, thank you for your input.
George
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Posted by Romy the Cat on
03-14-2007
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| George wrote: | | The remote is not a problem. Using a Xantech distributer, repeaters, and electric eye you can configure the two passive remotes in a foolproof, or nearly foolpoof, manner for about $75-100 total. Since I already had the basic Xantech gear the additional cost was some $15. The problem is that if you have the Placette exposed to both Xantech control and and direct line of sight from the remote the Placette will receive signals from two sources. However, Xantech makes an IR cover for just this purpose for $3 that prevents the Placette from receiving direct commands from the remote. So far I have not observed any difference in the level settings of the two passives when hooked up in this manner. |
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Hm, it is very elegant solution! I never thought about it….
| George wrote: | | Guy thought this was overkill and insisted the passive can drive several feet of cable without loss.......... |
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I disagree with him. Sure, anything can drive any length, the question is: in witch coordinate system the result should be evaluated. When we have a cable AFTER a passive voltage dropping then the dynamic and bass detritions will not convert sound in 1M cable into an absolute crap. If anything will happen negative then it happen very gradually. One meter is good 2 meters is good but 2.45 is bad? Sure not like this. Any cable AFTER any resistor is bad the only question is we have the necessary conditions to see it. Why do you think we place the plate loading resistors or grid/screen resistors right next to the tube socket instead of keeping them on the power supply side? Yes, I perfectly understand that my dislike of any passive preamps driving cables is a poor subject of my anal retentiveness and in most of the cases it is not really important. However, what is wrong with exercising anal retentiveness within the subjects of Absolute Audio if the entire audio as an occupation is a Mecca of anal retentiveness? Anyhow, despite of what Guy says I think his Active unit and it’s performance in relation to his Passive units (regardless the length of the cables) is self-evident.Rgs,
Romy the caT
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Posted by George on
03-14-2007
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| Romy the Cat wrote: | | However, what is wrong with exercising anal retentiveness within the subjects of Absolute Audio if the entire audio as an occupation is a Mecca of anal retentiveness? |
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Nothing. Why else would I post here? If I wanted a pat on the back and a "the cable won't matter" I could delude myself elsewhere. Still an interesting experiment from my point of view.
Thanks,
George
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Posted by Paul S on
03-15-2007
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I am thinking again about “detail” in the context of this thread. The issue is which, what sort and/or how much/many detail “should” we be able to hear at any given volume setting?
I have been guilty of enjoying details, etc. I knew were more obvious than they should be according to a given volume setting, relative to the putative/supposed volume of “the original performance”. I don’t always want my music played back at “live” volumes, yet I crave certain cues. It may be that I want something between “realistic” detail and “interesting” detail, given parity with other aspects of playback, and none of this to be confused with "neutral".
I still have too much work to do with my front end to conclude anything about the TAP and Shastakovich, but I just want you to know, Romy, as I sail by the window at the 54th floor), so far, so good…
Perhaps, Romy, you can comment on the Symphony # 10, Svetlanov/USSR Symphony/Melodia, to help with my bearings. I have only heard this performed live once in my life, many years ago.
Best regards,
Paul S
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Posted by Paul S on
03-18-2007
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So far it appears that one needn't look to the TAP for any sort of sonic help. I have been breaking my own "one change at a time" rule by futzing with a new (K&K) phono stage as well as the CD/bypass stuff, and everything I do to/with the system is readily audilble. This matters because I decided a long while ago that the "goal" for the system is "music", not simply a "listen-through" to a "literal rendition" of any given recording. CD playback has consistently sounded so similar through the TAP or bypassed that I cannot be sure of differences, and the TAP does not seem to harm CD. OTOH, I have a ways to go to get consistent sound from the new phono stage (another thread perhaps, if there is anything worth telling), and there is no way with the TAP to mitigate or balance any source problems, other than voume, phase or balance. This would not be worth mentioning if I was getting consistently musical sound, but I am not. The best so far is the best repro I have gotten to date, but any sort of change might throw the sound out of whack. For instance, I have in the past use the output taps on the ML2s to tune LF/HF and ambience. But with the TAP and the phono combination one change works two or more big effects, most of which sound like phase issues.
By the time I shut down the system today I was getting great sound and very good music from the phono system from my best records, and acceptable music and fair sound from lesser recordings. Because I have had the bass just right and the highs just right, etc., I know it is possible to get any given "area" right; but I have gotten everything right simultaneously just once with the TAP installed, and I could not lock it down.
Is this a job for superbuffer?
Best regards,
Paul S
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