This is my first post here, and I am hoping to obtain some help replacing the volume pot on my Counterpoint SA-1000. I hope that I have posted this in the correct area this time🙁. I have tried a couple of other avenues for answers, but have received no help. On to the experts... About four years ago I did a recap along with some parts upgrades (nothing substantial IMO), but would like to replace the stock volume pot. I have already ordered a replacement AudioNote, and I am aware that it has six tabs instead of eight as in the original. I have seen a few images of a different (six tab) pot installed, and can see that the extra two wires can be doubled up with on two of the tabs on the new pot. I have a schematic, but I am not knowledgeable enough to figure out how to do this. If anyone can help with this, I would very much appreciate that! Thanks, and thanks for all of the unacknowledged help in the past. Kevin
The fourth pin is the equal loudness tap. According to the circuit diagram you provided, your preamplifier does not have the equal loudness function, so the fourth pin does not need to be connected to the circuit. Pins 1, 2, and 3 are the same as the original potentiometer.
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ne5532,
Thanks for the response. I did read that the fourth pins are for a loudness tap, and as you stated, it is not applicable here. I apologize for not being more specific, but what should I do with the extra two wires? I have seen photos with them doubled up with other taps on the volume pot, or just no longer visible. Are you suggesting that they simply remain unconnected? I'm still just in Kindergarten as to the "why's" in this hobby 🙂
Thanks for the response. I did read that the fourth pins are for a loudness tap, and as you stated, it is not applicable here. I apologize for not being more specific, but what should I do with the extra two wires? I have seen photos with them doubled up with other taps on the volume pot, or just no longer visible. Are you suggesting that they simply remain unconnected? I'm still just in Kindergarten as to the "why's" in this hobby 🙂
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Yes, leave them unconnected.
One issue with that model is it has excessive gain and the volume control feeds the stage that runs open. Therefore you have excessive noise and the volume position is low while you have high level output. This also makes low level tracking a real issue.
We replaced a lot of volume controls due to low level tracking issues. I haven't bothered to look at the circuit in years to see if there was a nice way to drop the gain. You could add resistance in series with the top of the control (I would reduce the value also). I don't like that option either, but it would raise the control rotation for a given output.
I was the Canadian warranty for Counterpoint until they went under. The power supplies on most had to be redesigned to make them more reliable and stabilize the voltage while lowering noise.
One issue with that model is it has excessive gain and the volume control feeds the stage that runs open. Therefore you have excessive noise and the volume position is low while you have high level output. This also makes low level tracking a real issue.
We replaced a lot of volume controls due to low level tracking issues. I haven't bothered to look at the circuit in years to see if there was a nice way to drop the gain. You could add resistance in series with the top of the control (I would reduce the value also). I don't like that option either, but it would raise the control rotation for a given output.
I was the Canadian warranty for Counterpoint until they went under. The power supplies on most had to be redesigned to make them more reliable and stabilize the voltage while lowering noise.
anatech, Thank you very much! That was very helpful. I hope that it doesn't happen, but if some other problem comes up, it is good to know that such expert help is available from this forum. I am enjoying this preamp after pairing it with a better amp than I was using previously (Aragon 4004 vs. Hafler DH220). This modification might be as far as I wish to go, but one should never say never.
Hi AraPoint,
The SA-1000 is a starting point. The SA-2000, 3000 preamps are far better, total night and day. The SA-5000 is more complicated, but basically the same as the SA-3000.
Do not perform any mods to any Counterpoint you may see on the internet. Those folks destroyed those units with no improvements. I've had to resurrect a few. So stop there on your SA-1000 except to maybe repair it. There may be some changes to improve it, but they aren't coupling caps or increasing supply capacitance for sure.
I would turn the gain down on whatever following amplifier you use. With the SA-1000 they should either be tube input or JFet input. Don't connect it to drive a solid state amplifier with bipolar input transistors, that is a mismatch. A popular but stupid combination up here was an SA-1000 and a Bryston 3B or 4B. Dumb. The SA-2000 and up can drive any amplifier as they are buffered.
The SA-1000 is a starting point. The SA-2000, 3000 preamps are far better, total night and day. The SA-5000 is more complicated, but basically the same as the SA-3000.
Do not perform any mods to any Counterpoint you may see on the internet. Those folks destroyed those units with no improvements. I've had to resurrect a few. So stop there on your SA-1000 except to maybe repair it. There may be some changes to improve it, but they aren't coupling caps or increasing supply capacitance for sure.
I would turn the gain down on whatever following amplifier you use. With the SA-1000 they should either be tube input or JFet input. Don't connect it to drive a solid state amplifier with bipolar input transistors, that is a mismatch. A popular but stupid combination up here was an SA-1000 and a Bryston 3B or 4B. Dumb. The SA-2000 and up can drive any amplifier as they are buffered.
Thanks again anatech,
I have read that the SA-2000 and 3000 were much better in several different discussions. I appreciate the advice regarding when to stop. My past tinkering didn't involve any changes to the existing circuitry, and was prompted by the need for a repair. I am not using a tube amp, but I will research my solid-state ones. I'm fairly sure that the Hafler is a JFet input. I think that the Aragon is as well, but maybe this one is in the dumb camp (with me). The preamp sounds good to me in this combo, but perhaps it could sound better if there is a mismatch.
I have read that the SA-2000 and 3000 were much better in several different discussions. I appreciate the advice regarding when to stop. My past tinkering didn't involve any changes to the existing circuitry, and was prompted by the need for a repair. I am not using a tube amp, but I will research my solid-state ones. I'm fairly sure that the Hafler is a JFet input. I think that the Aragon is as well, but maybe this one is in the dumb camp (with me). The preamp sounds good to me in this combo, but perhaps it could sound better if there is a mismatch.
When I had my SA5.1, I brought home a Marsh 400 from an audio store to audition. It sounded absolutely awful, to the point that my wife told me if I buy that, divorce time. Might have had something to do with it, just a bad match. Sounded fine with an Odyssey Stratos. Never looked into difference with input stages on the amps.
So after some small amount of research, it appears that JFet input has high impedance while bipolar transistor (BJT) input has low impedance. Is there a better way to differentiate between the two if it is not clearly stated? The Aragon 4004 has an input impedance of 22k ohms. The Hafler DH220 has an input impedance of 47k ohms. Please correct me if I am wrong, but it seems that both of these amps are JFet input designs. I do recall that the Hafler/Counterpoint pairing was not as loud of the Aragon/Counterpoint pairing. In my uneducated mind, that is because of the higher resistance of the input in the Hafler amp.(?)
OK, wait a minute. The Bryston 3B and 4B have input impedance of 50k ohms. Clearly I am incorrect here. Somehow I have misinterpreted some reading. An answer to my underlined question above is becoming difficult for me to find. Oh well, keep on grinding.👍
OK, wait a minute. The Bryston 3B and 4B have input impedance of 50k ohms. Clearly I am incorrect here. Somehow I have misinterpreted some reading. An answer to my underlined question above is becoming difficult for me to find. Oh well, keep on grinding.👍
Hi AraPoint,
You pretty much have to look at the schematic.
This issue is a relatively high output impedance with the SA-1000 and SAx.1 series. Any variable input impedance will directly cause distortion. Never mind driving cable capacitance.
You pretty much have to look at the schematic.
This issue is a relatively high output impedance with the SA-1000 and SAx.1 series. Any variable input impedance will directly cause distortion. Never mind driving cable capacitance.
Hello again,
I found examples of these two types of inputs used in amps, the JFet circuit will look something like:
The BJT circuit will look something like:
The section of the schematic for the Aragon and Hafler amps that most closely resembles either one of the above:
So without actually understanding the details of how the circuits are different, it looks like what my amps use is the BJT circuit. Perhaps I still don't have enough knowledge to make that determination. So I might have a bad match for the Counterpoint SA-1000. It sounds pretty darned OK to me, so maybe my ears aren't as good as I thought. I have never compared the two different amp circuits. I apologize for littering the forum with beginner questions, but I really appreciate the time taken to respond and information!
I found examples of these two types of inputs used in amps, the JFet circuit will look something like:
The BJT circuit will look something like:
The section of the schematic for the Aragon and Hafler amps that most closely resembles either one of the above:
So without actually understanding the details of how the circuits are different, it looks like what my amps use is the BJT circuit. Perhaps I still don't have enough knowledge to make that determination. So I might have a bad match for the Counterpoint SA-1000. It sounds pretty darned OK to me, so maybe my ears aren't as good as I thought. I have never compared the two different amp circuits. I apologize for littering the forum with beginner questions, but I really appreciate the time taken to respond and information!