How did you get them?
I find it really frustrating that all of the good parts are either sold out or way too expensive.
Ok Nelson I would like to make a donation towards your idea to produce your own parts, designed 100% for audio use.
I would like to see complimentary JFets better than k170/j74, and complimentary Power JFets better than semisouth devices, at reasonable prices. If it is possible, I will make a donation toward it.
I find it really frustrating that all of the good parts are either sold out or way too expensive.
Ok Nelson I would like to make a donation towards your idea to produce your own parts, designed 100% for audio use.
I would like to see complimentary JFets better than k170/j74, and complimentary Power JFets better than semisouth devices, at reasonable prices. If it is possible, I will make a donation toward it.
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That circuit (post #8231) has very exact bias (about 7mA) on input BJTs through R4 and R5, R14 and R16.
It's tested circuit.
If you think of Vbe what is it - voltage between base and emitter, not just base to ground.
Circlotrons and xFETs are great, but they are not all what there is - es gibt auch die anderen Dinger zu spiel mit
Hi.Has anyone built amazing circlotron?I read the Amazing Circlotron and it seems a very good amplifier.Someone said it has lower PSRR.How an amplifier has lower/higher PSRR?Why circlotron have lower PSRR than F5?How to calculateThank you
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> How did you get them?
Through friends in Japan. Pretty difficult, and I always owe him a big favour.
> I would like to see complimentary JFets better than k170/j74, and complimentary Power JFets better than semisouth devices, at reasonable prices.
Just parallel 500x K170/J74. It's well known solution.
Patrick
Through friends in Japan. Pretty difficult, and I always owe him a big favour.
> I would like to see complimentary JFets better than k170/j74, and complimentary Power JFets better than semisouth devices, at reasonable prices.
Just parallel 500x K170/J74. It's well known solution.
Patrick
The devices are good but 2sk1530/j201 are 150watts devices but k2955/j554 are 100 watts.I think they will distort more than k1530/j201 ones(weak transistors give less sound and it will distort in high levels).Maybe k163/J44 + k1530/j201 will be a better choice.Or maybe 2x parallelled super matched k2955/j554 can be better.
We can buy easily to 2sk1529/2sj200 in my country.I did not try them yet.What do you think of them?Are they better complemantaries?
No, it doesn't.
In a nutshell circlotron is a balanced circuit and well balanced circlotron is very hard to beat. There are lot of threads here and articles all over the net about circlotron amps. Find them, read them, make an amp and you'll know...
No, that circlotron doesn't sound better than F5.
Read the posts very carefully and think about what you read...
If you use 2SK246/2SJ103 in replace of K170/J74 in the original F5 circuit(not cascode), how would you make them work? I know some people use 2SK246/2SJ103 in original F5 cirucuit and complain about output DC drifting.
Don't use them, unless it is for experimenting purposes.
Just buy yourself some k170/j74 devices and make it as designed.
I don't think dc offset would have anything to do with the devices, it would more likely be due to poor implementation of the thermistors.
I have tried both k170/j74 and k246/j103 on F5 circuit. In addition to the implementation of the thermistors, bias of k246/j103 is quite different, even though the Idss of BL grade is close to that of k170/j74. I know k246/j103 is a worse alternatve. However, I like the sound of the k246/j103 pair.
Oh no - not another question about heatsinks!
Yup. I have read the F5 thread twice, and most of the First Watt articles. I have even been keeping notes on where to find different discussions. I think I shall be perfectly happy with some Heatsink USA extrusions when I get to that item as I slowly accumulate parts. (I also think I will look into using some automotive header hi-temp black paint on them when the time comes.)
Question: what are the heatsinks that Nelson uses for the First Watt standard cases? I haven't seen anything about them in this thread, and wonder why they don't seem to be an option that people discuss. Folks certainly discuss just about every other aspect of the stock F5.
If they have been discussed in another thread, I will be happy to go search there, but would greatly appreciate a hint as to where such a discussion might be. The within-thread search works pretty good, but the general search can be a blunt instrument.
Thanks!
Bruce
Yup. I have read the F5 thread twice, and most of the First Watt articles. I have even been keeping notes on where to find different discussions. I think I shall be perfectly happy with some Heatsink USA extrusions when I get to that item as I slowly accumulate parts. (I also think I will look into using some automotive header hi-temp black paint on them when the time comes.)
Question: what are the heatsinks that Nelson uses for the First Watt standard cases? I haven't seen anything about them in this thread, and wonder why they don't seem to be an option that people discuss. Folks certainly discuss just about every other aspect of the stock F5.
If they have been discussed in another thread, I will be happy to go search there, but would greatly appreciate a hint as to where such a discussion might be. The within-thread search works pretty good, but the general search can be a blunt instrument.
Thanks!
Bruce
If you prefer the sound, then use them.
If you are having trouble biasing then you may need to change the drain resistors/trim pot to get better adjustment.
It's a one-off, the customer also owns the extrusion die.
Around $5k for the die, according to Papa.
JFET thermal coupling
I finally got my F5 boards populated and I thought I'd share a pic of the thermal coupling fin I made for the JFETs. It's just a little chunk of aluminum I made a fat T shape out of with a small hacksaw. After sanding, filing, and drilling this is the result. I used a bit of shrink tubing and thermal paste as well to finish them off. I'm hoping that these will help add some thermal mass to the first stage.
I finally got my F5 boards populated and I thought I'd share a pic of the thermal coupling fin I made for the JFETs. It's just a little chunk of aluminum I made a fat T shape out of with a small hacksaw. After sanding, filing, and drilling this is the result. I used a bit of shrink tubing and thermal paste as well to finish them off. I'm hoping that these will help add some thermal mass to the first stage.
bdbender, I would not use a paint on the heatsinks myself. I think it has been discussed (here or some other thread) and some folks were in favor of it, but I am very skeptical that black paint of any sort will not decrease the thermal transfer to the outside world due to the binder used - high temp paint I think is usually a silicone material, although I am not certain of that.
I'd just send it out for anodizing, set up for home anodizing (you can find it on line) or keep it natural...
Of course if you have ample heatsinking, maybe the loss due to paint is not significant.
_-_-bear
I'd just send it out for anodizing, set up for home anodizing (you can find it on line) or keep it natural...
Of course if you have ample heatsinking, maybe the loss due to paint is not significant.
_-_-bear