22g (AWG?) is quite thick for the currents in a line level stage.
24/25/26swg is more common for these very low currents and even then they are still much larger than the current actually requires.
If we could get the reliability and robustness from a 28swg or 30swg, then there may be a tiny, but probably inaudible, change in the way the signal passes through.
24/25/26swg is more common for these very low currents and even then they are still much larger than the current actually requires.
If we could get the reliability and robustness from a 28swg or 30swg, then there may be a tiny, but probably inaudible, change in the way the signal passes through.
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I've been using 30g solid core 0.999 silver wire for most of my line level signal wires for a while now. I got it from Myron Toback and threaded it through 28g PTFE spaghetti tubing from McMaster-Carr. Works great and is a tremendous improvement over stock ICs and internal signal wires.
Made mine with all Obligato caps, Ms audio/valab ladder type 10k attenuator
Also used teddy Pardo 12v power supply. compared very well to a Expensive tube pre, even though the tube pre had more mid range depth.
B1 had better bass detail and very extended highs.
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Hey guys, I have a question. Will this circuit work in a sort of inverse manner using j74 instead of k170? Have tons of those 🙂
Hello, I have a tecnical question regarding the capacitors on the B1. I tried mixing around with capacitors to get a more forward sound of this preamp. I have now redused the 10uf to a 0,1 uf sonicap gen 2. The amp sounds much more forward, but looses some bass. My question is: What does the 10uf capacitor do, what happens if I reduce its size and could I do any harm with changing this cap?
mattism
mattism
The original B1 does not use a split supply, this means that the output has half the rail voltage (about 9V DC if using 18V supply) on it. The cap is there to block the DC.
However the capacitor along with the resistor to ground (both in the B1 and the amp it is connected to) on the output also forms a high pass filter. If you reduce the capacitor too much you will reduce the bass output.
edit: as an example, say the amp you are connecting the B1 to has an input impedance of 25K then with a 10 uF cap the corner frequency will be approx 0.63Hz, but with a 0.1uF cap the corner frequency will be around 63 Hz! A lower impedance amp will be worse!
Tony.
However the capacitor along with the resistor to ground (both in the B1 and the amp it is connected to) on the output also forms a high pass filter. If you reduce the capacitor too much you will reduce the bass output.
edit: as an example, say the amp you are connecting the B1 to has an input impedance of 25K then with a 10 uF cap the corner frequency will be approx 0.63Hz, but with a 0.1uF cap the corner frequency will be around 63 Hz! A lower impedance amp will be worse!
Tony.
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Thank you for your answer. As I understand you it is not so wise to reduse the capacitor to much as I loose som protection from DC noice. Could I alter the frequence by altering the ground resistor (r105 and r205). Should I make it larger or smaller to get less bass?
mattism
mattism
I would increase the capacitor to at least 1uF. The issue is not just the output resistor on the B1 (which is from memory a very large value, 1 Meg Ohm if memory serves, which will have virtually no impact at all) but is more a function of the resistor to ground on the input of the amplifier (which could include the volume pot). This is not something that you want to mess around with.
I believe that the 10uF value will have been chosen so that even if the B1 is connected to a very low input impedance amplifier that the rollof is still acceptable.
I assume you are trying small caps due to cost/size? I'm not one to put too much faith in boutique caps. My feeling is that any decent quality film cap (polypropylene) of the appropriate size (10uF) should be fine. Any comparisons with caps of a different size than standard may be making changes that are to do with the different size and NOT because it is better quality or has better sonic characteristics.
Tony.
I believe that the 10uF value will have been chosen so that even if the B1 is connected to a very low input impedance amplifier that the rollof is still acceptable.
I assume you are trying small caps due to cost/size? I'm not one to put too much faith in boutique caps. My feeling is that any decent quality film cap (polypropylene) of the appropriate size (10uF) should be fine. Any comparisons with caps of a different size than standard may be making changes that are to do with the different size and NOT because it is better quality or has better sonic characteristics.
Tony.
I built my B1 some time ago and while it sounded nice I felt something was lacking.
I recently bought some Salas Shunt boards for another project and thought I might as well try it first in the B1 to see if it would make a difference to the B1's sound. I used the same SMPS, replaced the 15000uF caps on the B1 board by 1000uF Silmic II 's and fed the B1 a lower but much cleaner 20V. Boy was I in for a surprise
Anyone out there with a B1, if you are building a Salas Shunt for another project, give it a try in your B1 and see if it makes it shine like mine!
I recently bought some Salas Shunt boards for another project and thought I might as well try it first in the B1 to see if it would make a difference to the B1's sound. I used the same SMPS, replaced the 15000uF caps on the B1 board by 1000uF Silmic II 's and fed the B1 a lower but much cleaner 20V. Boy was I in for a surprise
Anyone out there with a B1, if you are building a Salas Shunt for another project, give it a try in your B1 and see if it makes it shine like mine!
I built my B1 some time ago and while it sounded nice I felt something was lacking.
I recently bought some Salas Shunt boards for another project and thought I might as well try it first in the B1 to see if it would make a difference to the B1's sound. I used the same SMPS, replaced the 15000uF caps on the B1 board by 1000uF Silmic II 's and fed the B1 a lower but much cleaner 20V. Boy was I in for a surprise
Anyone out there with a B1, if you are building a Salas Shunt for another project, give it a try in your B1 and see if it makes it shine like mine!
The Salas shunt dont require 1000uf much more like 100-220uF preferred. You better try that way.
I only had the 1000uF available so could not try anything smaller. It is working fine so I will probably leave it like this.
I may have put my initial post in the wrong thread. Here goes again:
I just got my B1 Buffer board with matching JFETs.
Question: Can this be modified to eliminate the extra input (really only need one input) and avoid the selector switch and extra wiring? Is it a simple matter of a few jumper wires or something? Just wondered if someone has done this as a simplification.
Thanks!
I just got my B1 Buffer board with matching JFETs.
Question: Can this be modified to eliminate the extra input (really only need one input) and avoid the selector switch and extra wiring? Is it a simple matter of a few jumper wires or something? Just wondered if someone has done this as a simplification.
Thanks!
Dang it. Build completed, but only the left channel is coming through with full volume. When the right channel is the only one - you can hear something, but it's very faint. I did use a heat sink on the legs of the transistors when soldering, but wondering if I still burned them out soldering one obstinate solder joint.
Are there any voltage test points to try to troubleshoot this? I've checked integrity of the input/output solder joints, so it must be something on the board.
Thanks.
Are there any voltage test points to try to troubleshoot this? I've checked integrity of the input/output solder joints, so it must be something on the board.
Thanks.
Measure the output noise+hum and the output offset of both channels.
Worth repeating with both inputs switched over.
Worth repeating with both inputs switched over.