| Magura |
What is the theory behind using a transformer for volume control...and are there any benefits??
I stumbled on a statement that of that resistive volume controls are only for applications with lack of space??
Cheers
Magura |
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| janneman |
Theory? I don't know. Ususally these are transformers with many taps, and a switch steps to each tap to vary the level. Look at Sowter's website. I guess they have some advantage regarding noise. But AFAIK they are less wideband than a good resistive vol control.
Jan Didden |
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| analog_sa |
| quote: | | But AFAIK they are less wideband than a good resistive vol control. |
No argument here. They generally provide better drive than high impedance resistive controls and in particular enhance low volume listening.
I didn't like the S&B102 much at first - the limited HF extension really used to bug me - but now i'm stangely addicted. There is an intriguing and satisfying fullness to the sound which generally improves listenabilty.
As the 102 Mk2 i own turned out to be a 'beta' version :), supposedly more stable but possibly inferior sounding to the original and with issues in balanced operation, i am now looking for a suitable upgrade. Maybe an autoformer? |
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| Peter Daniel |
Some of my friends also are not that much excited about S&B TVC. Comparing to resistive volume controls, transformers don't offer razor etched detail and extended highs.
But there is something about their sound, that can become addictive indeed. There is certain smoothness and "organic" touch that even stepped volume attenuators don't provide. Also each time I switch to TVC, the soundstage becomes bigger.
I find them very good with passive I/V conversion DACs and of course, GainClones.
I had the early version, with 19 steps and silver plated wires, and now I'm using the latest one, with upgraded wires (no plating anymore) and 23 steps, but I can't say any one is better than the other. |
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| Saurav |
| Autoformers - I'm using a pair wound by Dave Slagle (I think he posts here) that I'm very happy with. A few people have heard it, and have been pleasantly surprised. I haven't heard any S&B transformers though, so I don't know how they compare. |
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| analog_sa |
| quote: | | I had the early version, with 19 steps and silver plated wires, and now I'm using the latest one, with upgraded wires (no plating anymore) and 23 steps, but I can't say any one is better than the other. |
Peter
You seem to have a later 'beta' but not the original. Both versions seem to use bifiliar winding optimised for good paper response more than sonics. Seems like we owe this to the american marketing campaign. Plus they are no good balanced.
Saurav
| quote: | | I haven't heard any S&B transformers though, so I don't know how they compare. |
Ain't this frustrating? Dave Slagle certainly seems to know his stuff. And he doesn't seem at all concerned with pushing his product. Maybe i should simply bite the bullet and buy a pair. |
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| Saurav |
| quote: | | Dave Slagle certainly seems to know his stuff. And he doesn't seem at all concerned with pushing his product. |
True. I wouldn't have come to know of these if I hadn't happened to be visiting a DIYer in my neighborhood who happened to have a pair on loan which he happened to ask me if I was interested in.
| quote: | | Maybe i should simply bite the bullet and buy a pair. |
I would recommend them highly. Like I said, I don't know how they compare to other TVC variations, but to me they're leagues ahead of any ~ $300 active preamp I've heard - tube or SS, commercial or DIY. Not that I've heard everything out there... and I guess that statement is true for the S&Bs too.
I would say, go for it. You might be the first one to actually compare teh two :) |
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| Peter Daniel |
| quote: | Originally posted by analog_sa
Peter
You seem to have a later 'beta' but not the original. Both versions seem to use bifiliar winding optimised for good paper response more than sonics. Seems like we owe this to the american marketing campaign. Plus they are no good balanced.
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The last one was send to me directly from England. How you get hold of the original?
Bent Audio claims that they use better wire for improved sonics. |
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| Magura |
Does anyone know how such a thing looks inside?? Construction and so on?
Cheers
Magura |
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| analog_sa |
| quote: | | How you get hold of the original? |
http://www.diyhifisupply.com/access...ansformers.html
| quote: | | Also original style with sandwich windings in stock. These are more suitable to use in an active application since they can handle higher voltages than the bifilar. Also, they subjectively sound better even though >50Khz doesn't measure as well. |
It will be great if you decide to sample them. Besides, dealing with Brian is a pleasure. He also seems to speak 'canadian' :) |
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| Kuei Yang Wang |
Konnichiwa,
A few short remarks.
The original TX-102 used a quite complex winding geometry but required external RC Snubbers across the unconnected secondary section to reduce a nasty looking resonance in the 60KHz+ range at low volume settings. It sounded fine but did not measure that well at high frequencies and sounded better without snubber.
The design was changed to bifilar construction to cure this. The Bi-Filar TX-102 has a much superior High Frequency response to practically ANY resistive attenuator, though it may sound as if it has that much treble. With bifilar construction you get bnandwidth well above a few 100KHz. The downside is that you require a lower impedance source for equal performance (as bifilar construction has a greater amount of parasitic capacitance) and you need be more carefull when connecting the Transformer in a balanced to unbalanced or unbalanced to balanced application (it can still work fine for this BTW).
I have listened to both, the earlier version has a little more "magic" happening, a little more air and palpability, but the differences are smaller than from either to a TVC previously made but discontinued (the replacement is much inferior according to those who have tried both) by another manufacturer which I also tested and which sounds rather bandwidth limited and simplyfying in direct comparison to the TX-102 but STILL better, subjectively speaking, than a resistive control.
BTW, the original TX-102 specs are still on file and the original version (updated to 23-step secondary) can be obtained on special order, certainly via DIY-HiFisupply in Hong Kong and probably also from John Chapman.
As to "What is inside"? It is a transformer, consisting of a core (80%+ Nickel Alloy), winding former, winding (wire and insulation), can and potting compund. Core, wire, insulation and potting compound are specified to ensure good sonics and are different to the "common" usage in Pro/Domestic audio transfomers, the core is the largest size commercially available, the can's are specially made and tend to be the bottleneck in production together with getting enough core laminations.
Sayonara |
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| Steve Eddy |
| quote: | Originally posted by Peter Daniel
But there is something about their sound, that can become addictive indeed. There is certain smoothness and "organic" touch that even stepped volume attenuators don't provide. |
Now you know why I've been using input transformers for so long. :)
That smoothness and organic touch doesn't come so much from its being a volume control as its being a transformer.
If you're not needing a stand-alone passive attenuator having to drive a length of cable, and are driving a FET or a tube input, a Jensen JT-11P-1 or an 11P4-1 using a resistive attenuator of the same value as their ideal resistive loads (10k and 20k respectively), you can get that same smoothness and organic touch for significantly less than a pair of 102s.
Though for a stand-alone passive, I don't think you can beat the 102s.
se |
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| Peter Daniel |
There is an option for hard wired ground and floating ground. Floating ground didn't work with my first pair of transformers, but it seems to be working with the second one (single ended application).
Is there any subjectively perceived improvement to the sound when using "floating " option. I have to admit I didn't investigate it yet. |
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| SY |
| quote: | | a Jensen JT-11P-1 or an 11P4-1 using a resistive attenuator of the same value as their ideal resistive loads (10k and 20k respectively) |
That's exactly what I'm using as a passive pre these days. Works great for my relatively short (1.5m) cables. |
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| Steve Eddy |
| quote: | Originally posted by SY
That's exactly what I'm using as a passive pre these days. Works great for my relatively short (1.5m) cables. |
1.5m relatively short? I'd call that relatively long. :)
se |
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| Kuei Yang Wang |
Konnichiwa,
| quote: | Originally posted by Peter Daniel
There is an option for hard wired ground and floating ground. Floating ground didn't work with my first pair of transformers, but it seems to be working with the second one (single ended application).
Is there any subjectively perceived improvement to the sound when using "floating " option. I have to admit I didn't investigate it yet. |
First, all these "ground" options owe their existence to the fact that the unbalanced, RCA based interface in conjunction with modern Equipment suffers from many problems. A main one are circulating ground currents both at low and at high frequencies. If your source is "earthed" and your amplifier is "earthed" you will find often the signalcurrent actually passing through the mains wiring (Ground) as this is the lower impedance path. In this case you can use the "float" option and force the signal current into the desired loops (interconnects).
Equally, if you join the chassis of "insulated" equipment with a seperate "earth strap" you can "Float" the ground usually with sonic improvements.
The whole point is that there is no "right" connection but one that will sound bettter if you make sure to join all chassis through external heavy, low inductance ground wires.
Sayonara |
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| SY |
| quote: | Originally posted by Steve Eddy
1.5m relatively short? I'd call that relatively long. :)
se |
Well, it's probably about 200pF. So, worst case, I've introduced a rolloff with an f3 of 80kHz. I can live with that, since I don't hear much above 15K these days. |
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| Steve Eddy |
| quote: | Originally posted by SY
Well, it's probably about 200pF. So, worst case, I've introduced a rolloff with an f3 of 80kHz. I can live with that, since I don't hear much above 15K these days. |
Wasn't worried about that. Just that I've never used much more than half a meter to connect line level components. So it's a bit hard for me to think of 1.5m as being relatively short. :)
se |
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| Layberinthius |
| quote: | | Whispering with body" at very low level - those nice at midnight ;) - with previous voulume control sound seemed very "thin", this will be another surprise: you can have a great "body" listening also at low level . The tonal balance seems more natural & open also power flows more gently. At the end we find ourselves listening ( without fatigue) a level is so high we coulnd't speak . |
Schweet!
I've noticed with almost any speaker it does this ... sounds tinny at low levels.
I'll believe it when I hear it :P
| quote: | | " Another of the most notable things is that is you increase level all the part of the spectrum move in the same way . |
Doesn't that happen anyway?
| quote: | | There is a great sense of clearness. This is probably due to ground decoupling and ambience recovery. |
Ambience recovery, hmmm oooookaaay... :) |
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