2SC3854 in JLH 1969 Class A?

[becki200]

Hi everybody, i am going to build the JLH 1969 and will use the 2N3906 and 2N1613. I am not very happy with the 2N3055 (or TIP 3055) Because my heatsinks are not drilled for To-3 cans, i want to use power transistors in a T0 218 or similar case. Are the 2SC3854 a good choice? or what would you recommend? Thx and best regards Thorsten

 

[WuYit]

Hi,
is the 2SC3854 you are having genuine Sanken?

 

[becki200]

Hi i dont have it yet, i could get it pretty cheap from a surplus store here in germany. The picture shows a sanken. seems to be genuine.

 

[WuYit]

The 2SC3854 is much better than the TIP 3055, I would certainly go for it.

 

[selim]

Hi,

The JLH 69 amplifier seems to depend on the speed of the output transistors
for oscillation free performance.With transistors much faster than the 3055
class of transistors, you might get oscillation depending on the layout and
other parameters.Even with slower devices, the amplifier is a fantastic
performer.I used BD249 in mine.

Cheers

Selim

 

[becki200]

Hi WuYit, hi Selim

Thank you for your replies. Thought about the BD 249 but it is not easy to get them. Maybe ill try different transistors for the amp

Best regards Thorsten

 

[WuYit]

selim,
it´s generally true, but not a good reason to use poor quality transistors.

 

[becki200]

Hi got the answer from the seller of the 2sc3854. They are from China, so i will not buy them. What is wrong with BD249C? As i remember they were used in many amps in the eighties. I think i cant use 2SC5200 in an old class a design like this. Has anybody tried this?

 

[WuYit]

becki,
the BD249C is more reliable than a Chinese fake and hopefully will also allow you to build the amp without hassle (less a risk of oscillation).

 

[becki200]

WuYit you are right im not going to build something with a chinese fake