Hi all so what you saying is a TVC is the way to go with passive preamps and not a resistor attenuator,
I have played with a stepped resistor type and sound was nice but sounded so much better when it got to infinity!!! Or total buy pass 0db but as you no that is way to much volume be nice to have that sound in all volume steps!
I have played with a stepped resistor type and sound was nice but sounded so much better when it got to infinity!!! Or total buy pass 0db but as you no that is way to much volume be nice to have that sound in all volume steps!
Hi!
I am a big friend of TVCs or AVCs. But I would not recommend them in a passive pre unless you are sure that all your sources can drive the inductive load of a TVC well.
From my experience and listening tests from many people I know, some sources can sound rather mediocre when loaded by a TVC even if they claim low output impedance.
So for a passive pre I'd rather recommend a resistive volume control. If you want to use a TVC, design a proper buffer stage around it which drives it with low impedance and presents an easy load to your sources.
Best regards
Thomas
I am a big friend of TVCs or AVCs. But I would not recommend them in a passive pre unless you are sure that all your sources can drive the inductive load of a TVC well.
From my experience and listening tests from many people I know, some sources can sound rather mediocre when loaded by a TVC even if they claim low output impedance.
So for a passive pre I'd rather recommend a resistive volume control. If you want to use a TVC, design a proper buffer stage around it which drives it with low impedance and presents an easy load to your sources.
Best regards
Thomas
I have found wirewound pots to sound excellent at a modest price. much better than the ALPS black pots they replaced. I even got a good quality quad gang wire wound 10K pot for a PP balanced preamp for about €50.00, absolutely brilliant build quality and gang matching.
The only down side is they are linear, but at the 12'oclock to 3'oclock range they function fairly much the same and that is where most of the time they spend their life.
Shoog
The only down side is they are linear, but at the 12'oclock to 3'oclock range they function fairly much the same and that is where most of the time they spend their life.
Shoog
Using a dual bobbin does reduce capacitance. However, it doesn't distribute the capacitance evenly. If you interleave the autoformer windings and balance them like in the attached diagram you will have consistent high frequency behavior at every tap.
Attachments
Hi
If I start to add buffers to a TVC or AVC tell if I'm rong but isn't that starting to get into the active preamps and going a way from passive a little? As I do fine that a good CD player has around 2v of output and my amp with 1.29v input to power it at 135w. I have had 2 or 3 different active pre's hooked up and found that all had way to much gain and just sent amp into clipping at about 2'oclook. So makes you think y put one in the signal path?
Isn't it best to keep signal path to a minimum? So what to do a TVC or a AVC or even a good wire wound pot got to worry about channel matching with pots.
And thanks to all of you that have posted on this subject!
If I start to add buffers to a TVC or AVC tell if I'm rong but isn't that starting to get into the active preamps and going a way from passive a little? As I do fine that a good CD player has around 2v of output and my amp with 1.29v input to power it at 135w. I have had 2 or 3 different active pre's hooked up and found that all had way to much gain and just sent amp into clipping at about 2'oclook. So makes you think y put one in the signal path?
Isn't it best to keep signal path to a minimum? So what to do a TVC or a AVC or even a good wire wound pot got to worry about channel matching with pots.
And thanks to all of you that have posted on this subject!
Hi!
Yes, not just a little, that would be an active preamp.
Most systems have this problem of too much gain. You can design the active stage to have as much or little gain as you need. For example a 26 stage (if you want to go fancy with DHTs) into a 5.6:1 step down (Lundahl LL2745) will provide about 3dB gain, which is very little.
This is not always the best. Keep it simple, but not too simple.
While a purely passive TVC will work. In my experience an active pre will work better in most cases. It reliefs the sources from the burden to drive the inductance of a TVC.
Best regards
Thomas
Yes, not just a little, that would be an active preamp.
Most systems have this problem of too much gain. You can design the active stage to have as much or little gain as you need. For example a 26 stage (if you want to go fancy with DHTs) into a 5.6:1 step down (Lundahl LL2745) will provide about 3dB gain, which is very little.
This is not always the best. Keep it simple, but not too simple.
While a purely passive TVC will work. In my experience an active pre will work better in most cases. It reliefs the sources from the burden to drive the inductance of a TVC.
Best regards
Thomas
Can some one tell me the logic to compute the turns required for each tap? Any formula for this?
tbh, i never built this as my hand can not handle the wire size and several attempts i made ended up in failure, i asked my friends to make one for themselves and they liked it...if you can work on such small wires, then go ahead..
yes two bay bobbins ca be used...
M6 cores worked best here...
yes two bay bobbins ca be used...
M6 cores worked best here...
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