Hi Troy
The boards found there way to Belgium today.
Great quality! Krell can be really envious😱
Cheers
The boards found there way to Belgium today.
Great quality! Krell can be really envious😱
Cheers
Belgium in 3 days!!
GeWa-
WOW, 3 days!
Did they arrive in good condition?
Hi All-
ALL shipments were insured. Please email me if any were damaged or lost in shipment.
Thank you in advance,
Troy
GeWa-
WOW, 3 days!
Did they arrive in good condition?
Hi All-
ALL shipments were insured. Please email me if any were damaged or lost in shipment.
Thank you in advance,
Troy
ACD said:
Sadly I have to admit that you're right in your observationI had two 10-turns pot in my lib. and have obvious chosen the one with "wrong" pin-configuration 😡
Then there must be a part-number that will work, why not find wich, and call it a special design feature😉
Arne K
Cobra2:
There must be, however I have never actual seen this....
It may get very hard to find 🙄
There must be, however I have never actual seen this....
It may get very hard to find 🙄
Hi Troy
Yes, really amazing that it can go so fast.
The envelope was opened a little bit (customs maybe....) and was somewhat wrinkled. Boards where OK.
Cheers
Yes, really amazing that it can go so fast.
The envelope was opened a little bit (customs maybe....) and was somewhat wrinkled. Boards where OK.
Cheers
Guys perhaps we can barter some parts here.
I have many MJ21195/96 from ON. I also have extra MPSA42/92
and some MPSA06/56 as well as some 2sc2240 (but these are low in numbers)
I also have some old Windtunnel heatsinks for TO-3 (I can sell 3 of those and keep 4 for myself).
I live in Indiana.
Cheers! K-amps
I have many MJ21195/96 from ON. I also have extra MPSA42/92
and some MPSA06/56 as well as some 2sc2240 (but these are low in numbers)
I also have some old Windtunnel heatsinks for TO-3 (I can sell 3 of those and keep 4 for myself).
I live in Indiana.
Cheers! K-amps
I've got 27 pairs (!) of MJL21193/94's here if anyone has barter/buying power! Not looking to sell in this thread obviously, but they are TO-3p ones, not the TO-3 cans.... I've got no idea what people can offer but i thought i'd throw it up - speaker output terminals, rca connectors, very (very) good quality wire, etc? I've asked about some emittor resistors that i need, so i'll see what goes with that swap first 🙂
Aaron
Aaron
caps?
Aaron,
Speaking of parts, did your caps arrive? They should be there right about now...
Stuart
Aaron,
Speaking of parts, did your caps arrive? They should be there right about now...
Stuart
Re: caps?
Nope 🙁
I'm waiting *clock ticks*.... when it gets to 4mths time to get here, then i'll start worrying, but heavy packages rarely get lost, because the workers can't steal them 😉 If it takes less than 2mths i'll be surprised, if it's between 2-3, well it's normal 🙂
Aaron
Stuart Easson said:
Nope 🙁
I'm waiting *clock ticks*.... when it gets to 4mths time to get here, then i'll start worrying, but heavy packages rarely get lost, because the workers can't steal them 😉 If it takes less than 2mths i'll be surprised, if it's between 2-3, well it's normal 🙂
Aaron
Many years ago i ordered(and first payed) a Shure V15/III cartridge in the US(half the price), it cost me more than a year and a lot of writing to get it over here in Holland......
Bye, Loek
Bye, Loek
Hi there
Troy + Jan the boards look great cant wait to get mine.
Got a few questions
1.Ive got a 1 Kva 40 0 40 transformer is this over kill ?
2.What kind of Capacitor values are people going to have for each rail
would 50.000 uF per rail be ok ?
3.For the input transistors im thinking of using the 2N5401 and 5551 would these be ok ?I have other types if not. And Q111 an MJE340.
4.Q109 and Q110 on the schematic show they need to be heatsinked what kind of heatsink are people planning to use for this ?
5.For the emitter resistors i can only find some Dale 0.3 Ohm @ 5 Watt would these work ok ?
6.Are ZD101 and 102 definitely 27 Volt 1 Watt ? I have some
1N4750A if anybody needs some.
Sorry for all the questions
Best Regards
Anthony Kirby uk
Troy + Jan the boards look great cant wait to get mine.
Got a few questions
1.Ive got a 1 Kva 40 0 40 transformer is this over kill ?
2.What kind of Capacitor values are people going to have for each rail
would 50.000 uF per rail be ok ?
3.For the input transistors im thinking of using the 2N5401 and 5551 would these be ok ?I have other types if not. And Q111 an MJE340.
4.Q109 and Q110 on the schematic show they need to be heatsinked what kind of heatsink are people planning to use for this ?
5.For the emitter resistors i can only find some Dale 0.3 Ohm @ 5 Watt would these work ok ?
6.Are ZD101 and 102 definitely 27 Volt 1 Watt ? I have some
1N4750A if anybody needs some.
Sorry for all the questions
Best Regards
Anthony Kirby uk
Got my boards this morning, they look good. They are solid, nice and compact.
Thanks Guys
Anthony
Thanks Guys
Anthony
Just got my boards. They look great and very proffesional. Thanks!
By the way, per channel i use a 800VA 30-0-30 V torroid. I plan to build just like the schematic from Jan, so 3 endtransistors per rail (and per channel of course).
Can anybody tell me in that specific case the best quiest current?
By the way, per channel i use a 800VA 30-0-30 V torroid. I plan to build just like the schematic from Jan, so 3 endtransistors per rail (and per channel of course).
Can anybody tell me in that specific case the best quiest current?
I have just made this correction drawing for the Krell-Clone.
Place the board with the copper side up and make these corrections to the tracks to the pots 😉
Place the board with the copper side up and make these corrections to the tracks to the pots 😉
idle current depends...
Wim,
you have big transformers, so you can assume they aren't limiting you. The next questions are whats the size of your heatsinks and whats the rail voltage you have decided on. If the heatsinks are really, really huge or the rail voltage very high then the transistors themselves may become the limiting factor...
You can find the maximum idle current from the specs of the heatsinks and the rail voltage, lets say they are 0.5c/w, per channel, and you have 38V at the output of the caps...
Total voltage across the output stage is 76V, we don't want the heatsinks any hotter than 60c, ambient is assumed to be 20c...therefore maximum power in the sinks is (60-20)/0.2, or 200watts. Since power = volts x amps, the maximum current the heatsinking can deal with is 200watts/76V = 2.6amps. Since you have three output pairs, each transistor sees 2.6A/3, approx 0.85A, and dissipates 200watts/6 or 34watts.
If you are doing the high/low bias switch you would set high for a little below 085A per transistor, the low level you can choose based on your personal preference.
One thing to remember, this is a class AB amp, heavily biased into class A, if you drive it into a low enough impedance load, and the amp leaves class A, you will get more heat into the heatsinks, so the figures above are assuming you are NOT going to use it for Apogee scintillas, full power all the time. You'd want to add fans or double the size of the heatsinks etc for that task.
Stuart
Wim,
you have big transformers, so you can assume they aren't limiting you. The next questions are whats the size of your heatsinks and whats the rail voltage you have decided on. If the heatsinks are really, really huge or the rail voltage very high then the transistors themselves may become the limiting factor...
You can find the maximum idle current from the specs of the heatsinks and the rail voltage, lets say they are 0.5c/w, per channel, and you have 38V at the output of the caps...
Total voltage across the output stage is 76V, we don't want the heatsinks any hotter than 60c, ambient is assumed to be 20c...therefore maximum power in the sinks is (60-20)/0.2, or 200watts. Since power = volts x amps, the maximum current the heatsinking can deal with is 200watts/76V = 2.6amps. Since you have three output pairs, each transistor sees 2.6A/3, approx 0.85A, and dissipates 200watts/6 or 34watts.
If you are doing the high/low bias switch you would set high for a little below 085A per transistor, the low level you can choose based on your personal preference.
One thing to remember, this is a class AB amp, heavily biased into class A, if you drive it into a low enough impedance load, and the amp leaves class A, you will get more heat into the heatsinks, so the figures above are assuming you are NOT going to use it for Apogee scintillas, full power all the time. You'd want to add fans or double the size of the heatsinks etc for that task.
Stuart