Official LYNX Power Amp builder’s thread

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#46
hi jan,what distance(mm) from your PCB and Heatsink?

can i separate the heatsink of driver from output transistor?
because i think the pin(foot) of MJE15030 n 15031 is to short.

I will use 30pF to replace the original 33pF

Have you try lf357?
I see in datasheet this op amp is superior than lf356.
I know this devices is discontinue
and this device is still 'sale' in my favorite "electronic shop" with same price with lf356.:smash:

thank's
 
#47
crt;
I use 8 mm spacers, but you ca easily use 10 or 12 mm spacers.
can i separate the heatsink of driver from output transistor? because i think the pin(foot) of MJE15030 n 15031 is to short.
Click to expand...
??? Please look at the attached picture.
 

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#48
crt said:
Have you try lf357?
I see in datasheet this op amp is superior than lf356.
I know this devices is discontinue
and this device is still 'sale' in my favorite "electronic shop" with same price with lf356.:smash:
Click to expand...
When you put in so much money(?), I wouldn't use LF357 nor LF356. They are more noisy and designed in the 80's with all this means. OPA134 would proably be an excellent choice if you think OPA627 is too expensive. AD8610 in an adapter (I have nice adapters) would be an even better choice.
 
#51
I mean, the driver have a small heatsink (like in DX amp) and separated from the BIG heatsink for output transistor.

I have try to measure the pin only have 9mm length
when i use 10mm spacers the pins will not arrive to the top of PCB.

@peranders
In my town, is very hard to find OPA134 (mostly the shop only have opa2134) and the price is pretty expensive - Rp.75.000 (around US$8)
and the price of LF356 only Rp.4500 (US$0,5)

I don't have paypal or something like that
and I have a very limited budget😀

sorry for my BAD english
 
#54
crt said:
I mean, the driver have a small heatsink (like in DX amp) and separated from the BIG heatsink for output transistor.

I have try to measure the pin only have 9mm length
when i use 10mm spacers the pins will not arrive to the top of PCB.
Click to expand...
The driver transistors be mounted on the main heatsink and the pins are sufficiently long. What is the problem really? Why do you want them to be on a separate heatsink?
 
#55
crt said:
In my town, is very hard to find OPA134 (mostly the shop only have opa2134) and the price is pretty expensive - Rp.75.000 (around US$8)
and the price of LF356 only Rp.4500 (US$0,5)

I don't have paypal or something like that
and I have a very limited budget😀
Click to expand...
I'm sure you can ask nicely if somebody would donate two of their _free_ samples of OPA134 :idea:
 
#57
Hi Jan

I can´t find C114 and c115 on the component list.
But at the schematic it looks like 100nF 150V.

And Vishay MKP 1837 is 160V 10%, perhaps should go there.

For C104, 107, 108, 112, 113, the Vishay MKT 1817 is within the spec of 60V/100V 5% ?

Am I wrong ?:xeye:

And the 5W resistors are all wirewound ?

regards
 
#60
With the ClassAB amps I have built there have been no benefit from raising bias, on the contrary...there always seem to be an exact optimal bias point...usually the amps seem more stable with a specific bias...I usually also judge by the temperature on the heatsinks
Fore a stable soundstage left and right must be exactly alike
 
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