The contributer to this thread Mr danielwritesbac is not seen on this thread since long. We are not getting his valuable suggestions. Is everything OK for him?
Here is a nice implementation from Oscar:
https://www.diyaudio.com/community/threads/my-little-cheap-circlophone-c.189599/post-7017008
https://www.diyaudio.com/community/threads/my-little-cheap-circlophone-c.189599/post-7017008
Hi All,
since Daniel id is not active anymore.
i was curious as to how these transistors are markked up to be more suitable or less suitable. what parameters were considered.
Here is an explanation:
https://www.diyaudio.com/community/threads/my-little-cheap-circlophone-c.189599/post-2979650
I didn't find the original formula (it is probably lost somewhere in a heap of papers), but basically you determine the ratio between the Hfe at say, 100mA and 10A and you divide the Ft by this ratio; you then multiply the result by a convenient constant, to arrive at a value of ~1 for a median device, like the BD249C.
https://www.diyaudio.com/community/threads/my-little-cheap-circlophone-c.189599/post-2979650
I didn't find the original formula (it is probably lost somewhere in a heap of papers), but basically you determine the ratio between the Hfe at say, 100mA and 10A and you divide the Ft by this ratio; you then multiply the result by a convenient constant, to arrive at a value of ~1 for a median device, like the BD249C.
HI @Elvee
Since this is your design, I would like to know technically which transistors could be better usefull since the transistor mentioned by Daniel in the list are pretty rare and expensive now a days and some are discontinued therefore there are chance's of more Fake locally available....
So other than probably TIP3055 and 2N3055 no other transistor is available easily and cost effective less than 4 to 5 times of TIP3055.
I understand from your explaintion that your emphasis is on linearity of device for audio application.
Since this is your design, I would like to know technically which transistors could be better usefull since the transistor mentioned by Daniel in the list are pretty rare and expensive now a days and some are discontinued therefore there are chance's of more Fake locally available....
So other than probably TIP3055 and 2N3055 no other transistor is available easily and cost effective less than 4 to 5 times of TIP3055.
I understand from your explaintion that your emphasis is on linearity of device for audio application.
Hi there,
I have been keeping my eye on this amp for quite a while. Many thanks to Elvee for sharing the design and to Daniel for creating this tread. I think I have grown enough to build the amp
I am looking for an advice on the transistor choices:
1. My rails will be +35/-35V. My initial thought is to use 2SD1047 as the output transistors. Will this rail voltage be OK for these devices? Am I safe with them, or I should rather consider beefier devices? Initially, I considered MJL21194G but they are not available in Mouser until April next year.
2. Regarding the VAS, I plan to use 2SC5171 (I found a few in my drawer). However, I also found a bunch of 2SC3902. Will they be suitable for the VAS stage (Cob=14pF)?
3. I also have a few of 2SA1507 - would the be suitable as the drivers? If not, I will stick with BD140 (which I would need to buy).
I also have been working on the PCB for the amp, and I think I am close to have it finished.
I have been keeping my eye on this amp for quite a while. Many thanks to Elvee for sharing the design and to Daniel for creating this tread. I think I have grown enough to build the amp
I am looking for an advice on the transistor choices:
1. My rails will be +35/-35V. My initial thought is to use 2SD1047 as the output transistors. Will this rail voltage be OK for these devices? Am I safe with them, or I should rather consider beefier devices? Initially, I considered MJL21194G but they are not available in Mouser until April next year.
2. Regarding the VAS, I plan to use 2SC5171 (I found a few in my drawer). However, I also found a bunch of 2SC3902. Will they be suitable for the VAS stage (Cob=14pF)?
3. I also have a few of 2SA1507 - would the be suitable as the drivers? If not, I will stick with BD140 (which I would need to buy).
I also have been working on the PCB for the amp, and I think I am close to have it finished.
Attachments
Other than MJL you could look for MJW’s or NJW’s for same part numbers. They do come in fewer qty’s on Mouser.
Thanks guys.
Somewhere in this thread or in the original one (where circuit is discussed) someone wrote that he had tried successfully 2SC5171 in VAS. Since I have them I will try them first. 2SC3902 will go next. I suppose there is also TTC004B that (Cob=12pF) which could be worth trying.
Thanks for the pointers to {N,N}JWs. Indeed, available in Mouser.
I will report the progress of my build.
Cheers,
F
Somewhere in this thread or in the original one (where circuit is discussed) someone wrote that he had tried successfully 2SC5171 in VAS. Since I have them I will try them first. 2SC3902 will go next. I suppose there is also TTC004B that (Cob=12pF) which could be worth trying.
Thanks for the pointers to {N,N}JWs. Indeed, available in Mouser.
I will report the progress of my build.
Cheers,
F
Some of us have used KSC3503, you would need to add a Cap of 4.7pf in parallel since the Transistors pf is quite low.
I am currently using the above transistor for VAS. and it barely get's warm at +/- 22vdc