Haible Subtle Chorus

[spoontex]

Hi,

I found some of this boards in my house... 2010! And I will try to build it. But I have some questions.

JH. Subtle Chorus

You can build the vintage version with HA1457W ( obsolet ) or the modern with standard TL072. And with or without power transistors.

What is the difference of building the version with or without power transistors?

In the BOM of the main board say ( vintage )

HA1457W:

Vintage OpAmp in SIL package. If you don't find these, you
can build a modern version with TL072's (and without power
transitors) - there's a different BOM for this version.
Or, if you want to use the power transitor output stage
without HA1457W's, try other Dual OpAmps in the DIL8
package. I'm sure there are some that will work. (TL072's will
not work in that configuration - there's oscillation on
capacitive load!)

The question is. Worth build the modern version with power transistors? in this case, what IC I can try to avoid this oscillation?

Thanks.

P.D.: I've read somewhere that there are a Burr Brown IC that is very similar to the HA1457W. OPA604 maybe?

 

[f.aiseur]

Hi !
Sorry to Hijack the thread, i can start a new one if needed but, although JH's subtle chorus is quoted many times in the forum, there is no dedicated thread...

I'm in the build right now, sorry spoonex i can't answer your questions..
Im building TL072s - DimD version with 1x BBD pcb and 1x Main pcb


It's about capacitors : on the BOM for BBD and Main Pcbs there are some "electrolytic capacitors", "polyester capacitors", "ceramic capacitors", but also this intriguing "capacitors"...

I could find only two pictures of built Pcbs and it seems like the choices for those capacitors were as follow on both (including pictures from J.Haible's website) :

150pF : ceramic
330pF : ceramic
1nF : film
1,5nF : film
2,7nF : film
4,7nF : ceramic

So my question is : are those choices necessary to respect? Why?
Did anyone ended up using different parts for those values?


Thanks in advance!

Flo