The President of the NY St. Andrew's Society, why of course. I have never seen so much malt beverage consumed in my life, ever, than at their annual dinner.
If you've had enough Scotch it doesn't matter. They do force you to eat the haggis -- an acquired taste if I must say so.Did they force you to listen to bagpipes?
preamp gain
Hi Thanks Andrew,
i will diy a simple pre with a gain of 1.5 to 2 to try out.
My dac output is 2 V .
kp93300
Hi Thanks Andrew,
i will diy a simple pre with a gain of 1.5 to 2 to try out.
My dac output is 2 V .
kp93300
I reckon somebody is constantly trying to poison the subject
4KV might be even better
Last edited:
Let us burn our loudspeakers yeah enjoyable
Bit of a noob question I would assume, but when adjusting the bias via P1/P2 am I also changing the overall gain of the circuit?
In reading the discussion of the simplified circuit in the article, it would seem that it would for the input JFETs at least. The reason for the question is now that I have my amp biased and stable (not running thermistors right now and it took forever to get consistent), the central image is far left. The bias of the left channel is slightly below that of the right channel (~ 25mV lower / 0.05A).
Thanks
In reading the discussion of the simplified circuit in the article, it would seem that it would for the input JFETs at least. The reason for the question is now that I have my amp biased and stable (not running thermistors right now and it took forever to get consistent), the central image is far left. The bias of the left channel is slightly below that of the right channel (~ 25mV lower / 0.05A).
Thanks
Thanks kind of what I figured when I was adjusting, thus was quite surprised when I hooked it up to the main system... I will measure the output into a resistor this evening to see if there is a voltage output difference.
I seriously doubt that this is what causes your image to shift left. I'm not sure the gain is that much influenced by this bias current. As long as it is in the same ballpark, the vgs will be nearly the same and thus also the gain.
I would advise you to switch around the channels to see if it not just a matter of room acoustics or your source. Your idea about measuring is also good, just make sure you use the same signal generator/preamp channel for both your channels to avoid false positives.
A question for you: Why was it impossible for you to adjust the values closer?
Another one, which amp did you use before? IMHO, the F5 has a very detailed image, so I wouldn't be surprised if you are just hearing things on your records which were smeared before.
I would advise you to switch around the channels to see if it not just a matter of room acoustics or your source. Your idea about measuring is also good, just make sure you use the same signal generator/preamp channel for both your channels to avoid false positives.
A question for you: Why was it impossible for you to adjust the values closer?
Another one, which amp did you use before? IMHO, the F5 has a very detailed image, so I wouldn't be surprised if you are just hearing things on your records which were smeared before.
Thanks Gents, I will continue my troubleshooting this weekend and see what I find.
Without the thermistors, I have been fighting the temperature impacts of from one channel heating up the other, putting the cover on the amp increasing the bias significantly, etc., etc.). I have found it VERY temperature sensitive. It ended up being stable at 0.575V on the left side and 0.600V on the right with minimal offset (<3mV) with the cover on so I went with it.
My current amp in the main system is a DIY F3 and have always found it to be a focused central image. My speakers are spread ~10 FT center to center, so I have found it easy to detect imaging shifts (and when its right, a really great soundstage).
Without the thermistors, I have been fighting the temperature impacts of from one channel heating up the other, putting the cover on the amp increasing the bias significantly, etc., etc.). I have found it VERY temperature sensitive. It ended up being stable at 0.575V on the left side and 0.600V on the right with minimal offset (<3mV) with the cover on so I went with it.
My current amp in the main system is a DIY F3 and have always found it to be a focused central image. My speakers are spread ~10 FT center to center, so I have found it easy to detect imaging shifts (and when its right, a really great soundstage).
umbillical
Does anyone have a part number on some 3 conductor (with shield) cable that I can use for an umbilical cord to connect an external power supply to the amp?
I will try a one box solution first. But, I will most probably remove the power supply after some time to see if there is a worthwhile difference. But, I'm having a little trouble sourcing 3 conductor shielded cable. I think 16 gauge should be sufficient.
Thanks,
Steve
Does anyone have a part number on some 3 conductor (with shield) cable that I can use for an umbilical cord to connect an external power supply to the amp?
I will try a one box solution first. But, I will most probably remove the power supply after some time to see if there is a worthwhile difference. But, I'm having a little trouble sourcing 3 conductor shielded cable. I think 16 gauge should be sufficient.
Thanks,
Steve