I have ALS30A in my 6V6 line pre. But its some yrs ago, don't know if they make any better now.
Depending on your budget...have you looked at Parts Connexion?
All Brands Electrolytic Capacitors
Pricey but good stuff, good service and they ship anywhere. I've dealt with them for the last 9 years.
If I understand correctly, I only have 2 // 40 Hy chokes in series in my PSU...and now I have gotten rid of my CCS's and am using //12K = 6K quality resistor to load each channel....to get a more lively music with no hummmmms.....SSHV2 with CCS loading, to my experience, makes the music dull....and not lively...
I have just finished fitting the 2 boards in the box after a bit of thinking and changing around....(I will supply photos later...)
I start to individually test each board...and I find there is difference in performance between the 2 boards I have....
Board #1...the board I have been using before...and before testing my new board....I connected it to the PSU...and a 10K dummy load (then a //10K = 5K) load to the board.....and I set the TP to be 33mA....and the max V out from the board is 210V...and when change to 5K dummy load for the board, the max I can get is about 114V...input to the board = 288V
And when I disconnect board#1 and connect board#2...the LED become brighter....set the TP to be 33mA the same as board#1.....but...the max I get with 10K dummy = 276V....and with 5K dummy = 145V max....input to board#2 remains the same as 288V.....
Which part do you think that I need to change to make the 2 boards behave more the same...the same please??
Nothing become too hot to touch during this brief testing (15-20 minutes).....
How do I do that please?? (I need to buy more 2SK117)...
And then what would be the best 2SK117 to use??
On the other hand, if I use the 2 boards as they are....what are the negatives??
Thankyou, and cheers....
And then what would be the best 2SK117 to use??
On the other hand, if I use the 2 boards as they are....what are the negatives??
Thankyou, and cheers....
Its no better just more current in the Jfet useful if needed to go high B+. Could be just an led with more lumens, because for same Vo, there is same current in the Vref. To match Jfets for Idss is simple http://www.diamondstar.de/transistor_matching_jfet.html
1) do I need to use Jfet with higher Idss for higher possible B+??
2) if I turn up TP higher, say to 50mA, I can get higher B+...is it OK to do so??
2) if I turn up TP higher, say to 50mA, I can get higher B+...is it OK to do so??
Salas....I connected the two SSHV2 boards to the PSU...and the pair of tubes....VT-25A loaded by a pair of //12K (=5K) resistors.....
Funny thing happened....with 288V into the two boards....I can get 288V out...and quite stable as far as I can tell....but when I take the output down to 278V...they become less stable until say 268V....
Can I let them stay at 288 in and 288 out??
Funny thing happened....with 288V into the two boards....I can get 288V out...and quite stable as far as I can tell....but when I take the output down to 278V...they become less stable until say 268V....
Can I let them stay at 288 in and 288 out??
What you describe sounds like you move them about the non regulation zone with marginal spare current. They can regulate very close to Vin, but at Vi=Vo they just follow input, still when you go enough lower Vo the tubes bias for less current and they can control them at given TP CCS having some spare for themselves finally. That is why you can fix for more Vo with higher TP measurement.
After all, it is not like to be at the end of the world...!! (a few more hours around the world will confirm....haha..
OK....in layman terms....I would like to bias the tube at close to 8-9mA each (the V across the 6K load resistor is now at 40-50V) ....so should I set the TP at 30mA for each board?? is 3omA enough ?? what is the minimum mA??
I do not worry about the B+ ( the board output)....as long as I can set the voltage across the load resistor to be within 40-60V and have stability.....
My B+ transformer is rated at 125mA (a Canadian transformer)....my //choke is rated at 40mA each.....should I change my PSU when using 2 boards??
What should I do to go forward...what mA level to set TP at to try again....
Merry X'mas,
King
OK....in layman terms....I would like to bias the tube at close to 8-9mA each (the V across the 6K load resistor is now at 40-50V) ....so should I set the TP at 30mA for each board?? is 3omA enough ?? what is the minimum mA??
I do not worry about the B+ ( the board output)....as long as I can set the voltage across the load resistor to be within 40-60V and have stability.....
My B+ transformer is rated at 125mA (a Canadian transformer)....my //choke is rated at 40mA each.....should I change my PSU when using 2 boards??
What should I do to go forward...what mA level to set TP at to try again....
Merry X'mas,
King
The weakest link in my PSU in term of current is the //choke....which is 40 + 40 mA = 80mA...correct??
So should I set each TP at 40mA to start again??
Cheers,
King
So should I set each TP at 40mA to start again??
Cheers,
King