[John Chapman]

Hello!

For James:

the other replies catch many of your questions (1db steps, etc) but in answer to:

"If one so desired, could one build unbalanced four channel with remote ganged master volume and remote trim (+/-10 dB range) for two of the four channels?"

Maybe call or e-mail and we can back up to the exact application and work from there. It is not impossible to do a trim like that but it does have some possible gotcha's - like what do you do when you are trimmed up or down a lot and you get near the ends of the volume range, etc... Also how do we show the user exactly what the trim value is - possible with a lot of customization (programming) but that can be hard to do in a one off build.

Thansk!

John

[James Romeyn]

Thanks, John.  Yes, I see the +/-10dB trim function introduces at least two obstacles you describe, both of which did not occur to me.  Same as ever no "free lunch" no matter how hard and long we search!

This system employs a pure analog Trinaural Processor (stereo in, 3.0 or 3.1 output) between the source and multi-ch preamp.  I use the Bass trim most often, less often the C Ch trim (a Trinaural quirk is increased performance with C Ch attenuated several dB while processing spaced omni recordings ala Telarc, etc.) 

Trinaural can fit between stereo preamp and the power amps.  I suppose the Bent test would be whether its increased performance (simple remote stereo unbalanced kit) outweighs the loss of Bass trim and C Ch trim.

From prior link:

To be more specific, an ordinary transformer has separate primary (input) and secondary (output) windings, while an autoformer shares some part of the winding between the two.

It looks like an autoformer could be described as one side of a transformer (primary or secondary) with multiple taps.  Is this right?   

[John Chapman]

Hello!

"Trinaural can fit between stereo preamp and the power amps. "

Although it would get a bit elaborate you could put the trinaural after the pre then have a 1 or 2 more channels (center and maybe 0.1 sub if you need to remote trim that too) to do the trim that would slide into the feed from processor to the power amp. This is only warranted if you must have remote trims. If you want to trim manually (or just set up the system for a couple trims on a toggle switch, etc...) those feeds then there are less expensive and just as good sounding ways to do that.


"It looks like an autoformer could be described as one side of a transformer (primary or secondary) with multiple taps.  Is this right?   "

Yes - it is most like the secondary of a TVC volume control - the side with the volumes taps. As a matter of fact some folks preferred to wire the TVC's as autofomers  back (by connecting the secondary only) when I used to sell TVC units many years back.

Thansk!

John

[James Romeyn]

No comparison if you wan the ultimate in transparency & neutrality.  Bent TAP-X!!!

Jason,
Is your Bent autoformer balanced or unbalanced?  What is length of your IC, autoformer to NC400?  Cable type? 

Anand,
What is length of your balanced IC, autoformer to power amps (NC400 IIRC)?  Cable type?     

[jtwrace]

Is your Bent autoformer balanced or unbalanced?

Balanced.  In fact, mine was the first!

[James Romeyn]

Do you guys ever think about how strange it is that some members make and own stuff like the Bent item discussed here, that perform better than stuff priced up to ten thousand dollars in stores? 

[WireNut]

Do you guys ever think about how strange it is that some members make and own stuff like the Bent item discussed here, that perform better than stuff priced up to ten thousand dollars in stores?

Hell yeah, that's why we do it . It's not strange It's awesome

[poseidonsvoice]

Jason,
Is your Bent autoformer balanced or unbalanced?  What is length of your IC, autoformer to NC400?  Cable type? 

Anand,
What is length of your balanced IC, autoformer to power amps (NC400 IIRC)?  Cable type?   

Length is 1M, but it could be 10M for all I care as the Bent unit will drive it. Yes, NC400. The details of my system are finely delineated on my systems page.

BTW, the type of cable from what I recall seems to matter less with units designed around autoformers. So if you want to splurge, go ahead, but you don't have to. The measurements of the Bent unit (see earlier in thread) explains why, as well as the incredibly low output impedance.

Best,
Anand.

[jtwrace]

What is length of your IC, autoformer to NC400?  Cable type? 

I see that you added some text since I last answered.  2M from TAP-X > ATSAH and 1M from TAP-X to DCX > 2M from DCX to two of the bandpass sub amps.  The other subs have 6M (20') from the DCX.

All DH Labs.

[TomS]

I use 24' DH Labs Air Matrix XLR from a balanced TAP-X to a pair of Atsahs for mains and a 6' pair to a DCX2496 in parallel. No problems at all, even at that length and 20k ohm DCX input load.

[James Romeyn]

Do you guys run stock DCX2496 high pass to main speakers? 

John, would you consider a so-called "tour" of a Bent stereo autoformer?  Manual volume unbalanced is fine for me.  I need only audition for two-three days maximum.  If yes, consider me first on the list! 

[WireNut]

Ok, I have a question.

Do any of you guy's run a phono stage like the Vista Audio phono preamp into your TAP-X, or are you running a CD/DAC setup only thru your Tap-X?





 

[jtwrace]

Do you guys run stock DCX2496 high pass to main speakers? 

As noted above, the mains do not go through the DCX.  They run full range.

[poseidonsvoice]

Ok, I have a question.

Do any of you guy's run a phono stage like the Vista Audio phono preamp into your TAP-X, or are you running a CD/DAC setup only thru your Tap-X?

Yes, run all SOURCES to the TAP-X. It doesn't matter if it is a master tape, vinyl, cd/digital or a radio. All the matters is that you have enough overall gain in your system, as the TAP-X has 7dB or less gain (2X).

Best,
Anand.

[TomS]

I run both a Zesto Andros single ended output phono stage and an Auralic Vega balanced output DAC and I have way more than enough steam for both.

Same as others, I don't use the high pass out of the DCX2496.

[mgalusha]

More of the same here. Auralic VEGA (or whatever is at hand) and BHL phono through the TAP-X. I have ~20ft balanced runs to the power amps and another ~25 pair of balanced runs to a slightly modded DCX that runs the subs. IOW there is nearly 100ft of cable after the TAP-X. I have yet to encounter a source that doesn't work well.

I previously had a Lindemann 24/192 DAC that has only 1.4VRMS of output. Only if I wanted to turn it up to 11 would I end up with the TAP-X wide open and providing a bit of gain. The Auralic is 4.3VRMS and I've never come close to running wide open. Same with an assortment of other DAC's and phono stages I've had the opportunity to hear in the last few months. Note my speakers are ~97dB/W/M, so I need less gain than many folks. My TAP-X is the same as Anand's, Tom's and Jason's electrically, 4SE inputs, 2BAL and 2 of each on the output. I did start out with one of the old style very deep cases but after seeing the new one that was shallower I ran my TAP-X case through the table saw.

[TomS]

I still have the older deep case which I use to park an extra SUV in 

[James Romeyn]

I still have the older deep case which I use to park an extra SUV in 

I suppose, then, my Chevy HHR will easily fit?

[John Chapman]

Hello!

For James re: having a tour. I did do just such a tour many years back and it was actually quite a hassle. Too bad because I had (naively I guess) hoped it would be great fun!  Most folks were really good about it but a couple times folks hung onto it way longer than they promised and then add in some packing / shipping incidents and it was less than fun.... Worst of those was that one guy pulled the lid off then packed it in a box with Styrofoam peanuts. The thing showed up at the next stop jam packed full of the packing materials. Less than impressive.... Anyway with the small margins I run here I just can't afford the cost and time and hassles.

The best way to do that trial is to just grab a pair of Dave Slagles manual modules and slap some cables on them. They are here:

http://www.intactaudio.com/atten.html

Then you can play and just find a new home for them later or keep'em around as they are handy to have. Some guys use them for padding levels between amps, etc... If you sell them after you are done ( maybe to someone who does not solder ) I'll bet it would not be a great deal more expensive than the ship charges for a full on pre-amp.

BTW - here is a link to a project done with those modules by Dick Olsher:

http://www.enjoythemusic.com/diy/0611/slagle_autoformer_volume_control_modules.htm

If you don't need remote it's a super way to go and far less expensive than the AVC-1 route.

Thansk!

John

[WireNut]

John,

Great information as always. Your honesty, integrity, and knowledge are inspiring. Thank you once again.

Steve