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   Home » Audio Discussions » Another light for the LS tunnel: transformer-attenuators? (27 posts, 2 pages)
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  »  New  The ultimate buffer – light in the end of a tunnel..  A few minor corrections...  Audio Discussions  Forum     36  385843  04-28-2005
  »  New  Passive transformer based preamp..  Re: Thorsten's preamp idea...  Audio Discussions  Forum     41  464405  10-22-2005
04-01-2007 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,571
Joined on 10-12-2006

Post #: 21
Post ID: 4126
Reply to: 4032
If you're determined to try a "neutral" LS...

My a-musical woes, mentioned briefly above, were traced to the ML2s' fading drivers.  This report is written after the 6N6Ps were repalced.  As it turns out, the TAP did not figure into the problems, and minor system changes do not effect things as markedly now as when the bad drivers were messing with the sound and the music both.

Based on CD bypass and comparing CDs with "the same" LP the TAP is as much like "nothing" as I have experienced to date.  Since I had futzed with my phono source, unwittingly trying to compensate for the ML2s' fading drivers, I had to re-tune the system starting with CD as a basis once I'd discovered my mistake and replaced the bad 6N6Ps.

I am pleased with the TAP's "neutrality" in my system, which features short ICs, low impedance feeding the TAP and (apparently) high-enough input impedance into the ML2s.  Basically, there's not much to tell about the TAP.  Music gets through/comes across fine, so any subtractive effect I might be missing is not wrecking the music.  The TAP does not "overload" from anything I have fed it.  It makes NO sound of its own, even cranked wide open.  One caveat might be that studio "techniques" are now utterly apparent, albeit this does not interfere with the music in my system.  Although the TAP does not "highlight" engineering hijinks or poor recording, it does seem to render this sort of stuff as apart from the music, and I like this.

I am not "recommending" this component, just reporting, and in this case results are positive.  You can link from the BENT Audio website to a white paper on the S&B 102 [TVC] if you want to run the math and/or are concerned about possible effects of impedance/loads, etc., or if you are simply one to do your homework.

Best regards,
Paul S

04-02-2007 Post does not mapped to Knowledge Tree
drdna
San Francisco, California
Posts 526
Joined on 10-29-2005

Post #: 22
Post ID: 4130
Reply to: 4006
Romy, what are your listening impressions of this?

 Romy the Cat wrote:
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?


It is unavoidable, the physical aspects of the audio system affect the sound.  Paper cones are different than ceramic cones.  Soft wood makes better horns.  The answer to the transformer attenuator question is simply if it accomplishes something better than resistors for the sound.

It goes without saying that the transformer attenuator has a LOT of problems, LOADS of problems with impedence etc.  It is a terribly flawed thing.  BUT every audio part is a compromise.  The real question is whether despite these audible flaws (which will present additive distortions in coloration and timbre I expect), the transformer attenuator has fewer of the additive and subtractive distortions that resistor-based solutions have. 

I haven't listened so I can't speak eruditely about it, but I hope perhaps Romy has had the opportunity to have heard these transformer attenuators and can comment on how they sound in an optimal setting?

Adrian

04-15-2007 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,571
Joined on 10-12-2006

Post #: 23
Post ID: 4213
Reply to: 4001
Getting ambience, etc. from Shastakovich (and Verdi)
Well, Romy, it took me a while but I finally got the cobwebs cleared out of the phono stage, and the Shostakovich 10th was totally engaging as music (via the TAP). The recording is the (late 60s) Melodiya (stereo) with Yevgeny Svetlanov/USSR Syphony Orchestra.  I am not familiar with this performance/recording, but the "liner notes" do not describe it well, IMO.  In any case I really recommend it musically and as a subject for the Music Discussions.  I also enjoyed for the first time with this phono stage the very fine 1960 (CR Fine engineered) Mercury "Rigoletto".  You suggested listening for/to low-level ambience, rhythms, pronunciations, etc., and the TAP is also transparent to this as well as presenting the grand scale (and attendent ambience) of these wonderful performances/recordings.

Of course, it is partly "Sunday power grid", but the TAP is passive, after all.  I hated to shut it down today.  If a buffer stage improved on this I would never turn off the system!

I will be breaking out and cleaning up for play a lot of symphonic records I have not enjoyed for many years.  What a treat!

Great music is such a blessing in a savage world.

Best regards,
Paul S
06-17-2007 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,571
Joined on 10-12-2006

Post #: 24
Post ID: 4623
Reply to: 4213
Something gained:
OK, I think I can say now that the TAP does have some "beneficial effects" in my system.  It is rather like the effect of a LO MC step-up transformer, but not so pronounced.  The "beneficial effect" is to somehow present raw signal without as much "glare" or "hash" as the wire itself would introduce.  This also might come across as greater dynamics, but I don't think it is that.  And, oddly, "colors" seem to be "re-constituted", with less "bleed" and less "scatter" or "ghosting".  The TAP seems to do this without significantly diminishing colors or color range, either, and neither does it "heat up" the color.

No "help" with timing that I can detect, but no harm, either.

Remember that I have tailored my system to the TAP's electrical idiosyncracies, so don't try this at home.

That's about it for now, and likely for a while, as I am moving again (!).

Best regards,
Paul S
06-26-2007 Post does not mapped to Knowledge Tree
morricab
Posts 51
Joined on 07-13-2005

Post #: 25
Post ID: 4670
Reply to: 4005
attenuation order
Hi Romy, I see here that you are of the mind that putting the attenuator AFTER the gain stage has negative consequences for the sound.  I agree totally with this and had a discussion with Charles Hansen regarding this as well that the attenuator should go BEFORE the gain stage(s) so that the output of the preamp is unfettered.  I think it may have negative consequences with regard to then driving the cable properly, what do you think?  However; if you put the attenuator right at the input of the amplifier, ie. AFTER the cable, then maybe the effect is far less detrimental to the sound.
Cheers,
Brad
06-27-2007 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,049
Joined on 05-28-2004

Post #: 26
Post ID: 4674
Reply to: 4670
… Putting the attenuator after the gain stage

 morricab wrote:
…. putting the attenuator AFTER the gain stage has negative consequences for the sound….

Well, yes and no. In the new 6 channels version of Super Milq I will be use 2 stepped attenuators: for Injection Channel and for the Tweeters. Both of them will be line level, sitting between the input jack and the first stage grid, so essentially the resistors will be driving a few inches of cable – not a big deal at all, particularly cince I do not need in both channels any LF…

Surely the advantages to roll off voltage at line liven are very obvious, and do not forget that you have the tubes ruining at lover grid current – always helps… However, I would propose that the line-level advantages are inversely-proportionally to frequency. When we have any more or less LF driver then it has a lot of reactance that is being return back to amplifier. A speaker acts like a motor-generator sending the waves across the cable. Many aspects of dumpling in place in there and when we put a resistor (regardless of its location) then the resistor begins to play in this game. I, for instance, clearly hear change in sound when I put .3dB divider on my LF section.

However, with HF the effect is different. The tweeter reactance back to amp is negligible, dumping is way less critical and the presents of a resistor at speaker level is not so critical. I will still go for line level though in my case…

Rgs, Romy


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-07-2009 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,571
Joined on 10-12-2006

Post #: 27
Post ID: 12177
Reply to: 4674
Thinking About the "Optimum" Pre-Amp
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As with everything audio, one has to put it in context in order to evaluate it.  In my case, the ML2s have a reasonably "high" and stable input impedance, the TAP TVC has a reasonably low (and totally stable) output impdance, and my cable runs are short.  This in itself creates an effective "buffer", and the "inductance" presented by the TAP in this case is truly negligible with respect to frequency response.  Also, despite all the wire, the thing has relatively low ESR, so in this case it does not "write its own curve" with a reactive load (which it does not see, in my case).

Still, if people asked me, then I would "recommend" the Placette, if only because it is effectively BUFFERED, and for most of the dimwits out there this will probably prove to mean more than other things they merely think would mean something.

Shoppers: Take Note.

Paul S
Page 2 of 2 (27 items) Select Pages:  « 1 2
   Target    Threads for related reading   Most recent post in related threads   Forum  Replies   Views   Started 
  »  New  The ultimate buffer – light in the end of a tunnel..  A few minor corrections...  Audio Discussions  Forum     36  385843  04-28-2005
  »  New  Passive transformer based preamp..  Re: Thorsten's preamp idea...  Audio Discussions  Forum     41  464405  10-22-2005
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