If you are serious about it and want to proceed with those Toshiba cascodes from Ampslab, I will offer to buy them and ship some to you, free
Or if you find others of their specials more suiteable
Or if you find others of their specials more suiteable
Last edited:
I am definitely interested in this one. However I am a slow mover.
I am in the process of building cases, which could take me a couple of months.
I am in the process of building cases, which could take me a couple of months.
There is a bit of a balancing act with this one. The more voltage you put on the rails the less bias current you can use. There is a point where the cross over distortion is greater than the benefits given by the the cascoded input eg at 20V peaks (or higher) into 8 ohms.
1.2 Amps is the absolute minimum.
2.4A or higher is better but the heat starts to increase significantly with 40V rails.
So performance is excellent at low power output but to get good results (ie better than the standard version) at high power output the heat dissipation will be pretty high.
I hope this makes sense.
Too sum up to get excellent performance at both low and high power ouput you need at least 2.4A and 40V rails.
ie You need 40V rails for improved Low power performance and 2.4A or higher for improved High power performance.
1.2 Amps is the absolute minimum.
2.4A or higher is better but the heat starts to increase significantly with 40V rails.
So performance is excellent at low power output but to get good results (ie better than the standard version) at high power output the heat dissipation will be pretty high.
I hope this makes sense.
Too sum up to get excellent performance at both low and high power ouput you need at least 2.4A and 40V rails.
ie You need 40V rails for improved Low power performance and 2.4A or higher for improved High power performance.
Last edited:
Hello
Can I use 2SJ162/2SK1058 power Lateral mosfet or 2SJ77/2SK214 driver mosfet all original Hitachi ?
Do someone has some layout for the cascode verison ?
For these higher power verison I have two 30-0-30V 430VA toroidal transformers , I would like to give a try!
Thanks
Greetings
Can I use 2SJ162/2SK1058 power Lateral mosfet or 2SJ77/2SK214 driver mosfet all original Hitachi ?
Do someone has some layout for the cascode verison ?
For these higher power verison I have two 30-0-30V 430VA toroidal transformers , I would like to give a try!
Thanks
Greetings
Go for it.
Bias around 1.7A to 2.4A, or higher if you have the necessary heatsinking.
Bias around 1.7A to 2.4A, or higher if you have the necessary heatsinking.
Attachments
Last edited:
Aint that sweet🙂
If you are 100% certain those Toshibas are the ones we go fore I will set in motion asap
If you are 100% certain those Toshibas are the ones we go fore I will set in motion asap
Last edited:
Maybe hold off here, Nelson or someone else might have some more ideas about this one.
There is another benefit here, it looks like the cascoded version has about another 20dB improvement in PSRR
There is another benefit here, it looks like the cascoded version has about another 20dB improvement in PSRR
The other alternative is, if you don't exceed 30V rails then you won't need cascode operation.
You will also be able to bias higher.
You will also be able to bias higher.
I'm running 32V on my F5 with 1.2amps bias.
I have had them running since March with no problems.
I have had them running since March with no problems.
Yes 32V is fine, you could probably also go to 35 Volts without issues.
But it is good to allow some safety margin.
But it is good to allow some safety margin.
Might look like this
One channel
Not finished
Semi hardwired
One channel
Not finished
Semi hardwired
Attachments
Last edited:
4 output pairs, yes
But I might go up to 6 pairs
Supply is on the picture
Just the trafo is in an integrated wooden base below heatsinks
Supply caps and bridge(double) above trafo
NPN and PNP outputs on each side on their own respective heatsink
Its a mono amp you see
Caps etc is in a inside box to shield from heat
I expect it to give very effective convection cooling on inner side of heatsink
The hot air that goes upwards along inner side will enhance airflow on the outside as well
But I might go up to 6 pairs
Supply is on the picture
Just the trafo is in an integrated wooden base below heatsinks
Supply caps and bridge(double) above trafo
NPN and PNP outputs on each side on their own respective heatsink
Its a mono amp you see
Caps etc is in a inside box to shield from heat
I expect it to give very effective convection cooling on inner side of heatsink
The hot air that goes upwards along inner side will enhance airflow on the outside as well
Attachments
Last edited: