I've been impressed after living many months with a Tortuga Light Dependant Resistor volume control. SQ went up again when I tweaked a Yaqin CD3 (6SN7) tube buffer to add to it. Even though for some reason the Yaqin sounds better placed upstream from the Tortuga.
This leaves the 20k impedance Tortuga VC playing into the 20k input impedance of my power amp. Thinking my system would benefit from an output buffer to help with dynamics/punch, I have a solid state buffer kit (also from Tortuga) on the way. BUT I would like to keep the tube magic (or distortion--call it what you will) I now enjoy. But I would like to do this in the best way possible i.e. retaining the tube magic while minimizing noise and impacts on clarity and immediacy.
My first thought was to find a minimal-circuitry tube buffer that can use 6sn7s. I was perusing the Glassware site and the 12VAC tube buffer caught my attention. Maybe because the Tortuga stuff runs on 12V or maybe because I had just been reading about people's success running 6SN7s at low voltages, attaining lower noise figures as a result. Then luckily, I realized I don't really have enough info to know what direction to take.
So my questions are:
1) Can I get a meaningful increase in SQ by replacing the Yaqin upstream of the VC with another type of tube buffer-- OR -- some other approach to injecting a bit of "tubeyness"? (See as only one example John Broskie's balancer and unbalancer boards.)
2) If yes, what specifically would you suggest? If it's available in the EU that would be a plus.
Thank you in advance -- Rob
This leaves the 20k impedance Tortuga VC playing into the 20k input impedance of my power amp. Thinking my system would benefit from an output buffer to help with dynamics/punch, I have a solid state buffer kit (also from Tortuga) on the way. BUT I would like to keep the tube magic (or distortion--call it what you will) I now enjoy. But I would like to do this in the best way possible i.e. retaining the tube magic while minimizing noise and impacts on clarity and immediacy.
My first thought was to find a minimal-circuitry tube buffer that can use 6sn7s. I was perusing the Glassware site and the 12VAC tube buffer caught my attention. Maybe because the Tortuga stuff runs on 12V or maybe because I had just been reading about people's success running 6SN7s at low voltages, attaining lower noise figures as a result. Then luckily, I realized I don't really have enough info to know what direction to take.
So my questions are:
1) Can I get a meaningful increase in SQ by replacing the Yaqin upstream of the VC with another type of tube buffer-- OR -- some other approach to injecting a bit of "tubeyness"? (See as only one example John Broskie's balancer and unbalancer boards.)
2) If yes, what specifically would you suggest? If it's available in the EU that would be a plus.
Thank you in advance -- Rob
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It is a Denafrips Terminator DAC with output Z of 625R.
The Yaqin buffer has input Z of 100K and output Z of 900R.
The Tortuga VC has a 20K impedance.
Input Z of the MC452 power amp is 22K.
Input and output impedances of the solid state buffer I will be receiving in a few days are unknown.
But as it was built for this purpose, I think we can safely assume the input Z is very high and the output Z is very low. BTW Morten, the owner and designer at Tortuga says that although 10X difference between output and input Z is the standard, for passive set ups 50X difference between is considered the ideal.
The Yaqin buffer has input Z of 100K and output Z of 900R.
The Tortuga VC has a 20K impedance.
Input Z of the MC452 power amp is 22K.
Input and output impedances of the solid state buffer I will be receiving in a few days are unknown.
But as it was built for this purpose, I think we can safely assume the input Z is very high and the output Z is very low. BTW Morten, the owner and designer at Tortuga says that although 10X difference between output and input Z is the standard, for passive set ups 50X difference between is considered the ideal.
There's no ideal in engineering, but as a rule of thumb, a factor of five is enough for the ratio
of load to source impedance. But distortion can increase if the load is smaller than around 5k
for some solid state circuits, regardless of the output impedance.
Independent of that, you also need to confirm that the output coupling capacitor in the source
is large enough to not lose bass into the load. Generally, a 10uF output capacitor is large enough
into a 10k or higher load. For tube sources, a 1uF capacitor is large enough into a 100k load.
of load to source impedance. But distortion can increase if the load is smaller than around 5k
for some solid state circuits, regardless of the output impedance.
Independent of that, you also need to confirm that the output coupling capacitor in the source
is large enough to not lose bass into the load. Generally, a 10uF output capacitor is large enough
into a 10k or higher load. For tube sources, a 1uF capacitor is large enough into a 100k load.
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Yes, good advice. I know what you mean, I often use the V-Cap coupling cap calculator to size caps. But not sure what the value is in the DAC. Will check this now.
And in regards to my questions, are you recommending I just continue to go with the Yaqin? That it is about as good as any other method of getting tube sound into the system?
And in regards to my questions, are you recommending I just continue to go with the Yaqin? That it is about as good as any other method of getting tube sound into the system?
I'd experiment with what you already have. There are several possible combinations.
Try them all, a few days at a time for each.
no buffer - LDR - amp
Yaqin buffer - LDR - amp
Yaqin buffer - LDR - Tortuga buffer - amp
Tortuga buffer - LDR - amp
Tortuga buffer - LDR - Yaqin buffer - amp
Try them all, a few days at a time for each.
no buffer - LDR - amp
Yaqin buffer - LDR - amp
Yaqin buffer - LDR - Tortuga buffer - amp
Tortuga buffer - LDR - amp
Tortuga buffer - LDR - Yaqin buffer - amp
Ok can do.
Some of the trials have already been done. I think I spent a month working on the first and second options in your list.
It was difficult because there were clear trade offs. The system sounds good with just the volume control sitting between DAC and Amp. But the tubes brought something extra in terms of space around instruments, imaging and tone. The downside was they inhibited that sound of a direct connection, immediacy, dynamics internal to the sound.
My hope is that the new solid state buffer with big drive current might get back some of what the tubes took away. I thought to do this it would have to sit between the VC and the power amp. I base this on my experience of the Yaqin not doing well driving my amp in my setup, but also on comments on the internet that the Yaqin does not have the current to successfully drive solid state power amps. But I will try it both ways. Perhaps the SS buffer can do its thing also sitting in front of the VC?
Some of the trials have already been done. I think I spent a month working on the first and second options in your list.
It was difficult because there were clear trade offs. The system sounds good with just the volume control sitting between DAC and Amp. But the tubes brought something extra in terms of space around instruments, imaging and tone. The downside was they inhibited that sound of a direct connection, immediacy, dynamics internal to the sound.
My hope is that the new solid state buffer with big drive current might get back some of what the tubes took away. I thought to do this it would have to sit between the VC and the power amp. I base this on my experience of the Yaqin not doing well driving my amp in my setup, but also on comments on the internet that the Yaqin does not have the current to successfully drive solid state power amps. But I will try it both ways. Perhaps the SS buffer can do its thing also sitting in front of the VC?
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