Shaka 5 parts swap?

[Al Heeley]

Just starting a Shaka 5 build. I have a few Q's I hope you guys can help me out with. Trying to make the best use of some of my surplus components.
(Jack Orman's schemaitic on http://www.muzique.com/schem/shaka5.gif)
1) TL072 dual op amp jfet - can I use an LM4558 or 1458 type instead?
2) J201 jfet transistors - ok to use 2n5457 type instead?
3) IRF520 power mosfet - my local parts supply has only an IRF510 - is that going to be ok instead?
4) 1N34a germanium diodes - I have a load of 4148's - will they do the same job?

Questions about suggested mods:
a) Jack's schematic states "increase C2 to allow full range response". Original value 1uF. What would be a good value for this?
b) Also stated "Increase C5 (originally 220pF) to cut harshness of clipping diodes". Any suggestions? I thought I'd go for 560pF (it says up to a max 0.01uF.)
c) "Increase C6 (0.01uF) to allow full range response from mini booster". Would I be OK putting a 0.022 in there instead?

[Al Heeley]

*-<bump>-*

[aron]

1) TL072 dual op amp jfet - can I use an LM4558 or 1458 type instead?

Yes, provided you use the correct pins.

2) J201 jfet transistors - ok to use 2n5457 type instead?

Yes. Should be ok.

3) IRF520 power mosfet - my local parts supply has only an IRF510 - is that going to be ok instead?

Yes.

4) 1N34a germanium diodes - I have a load of 4148's - will they do the same job?

They will work but it will change the clipping threshold a bit.

Questions about suggested mods:
a) Jack's schematic states "increase C2 to allow full range response". Original value 1uF. What would be a good value for this?

You would have to try different values there.  I thought 1.0uF would allow full response. I usually use a much smaller value like .02uf or so.

b) Also stated "Increase C5 (originally 220pF) to cut harshness of clipping diodes". Any suggestions? I thought I'd go for 560pF (it says up to a max 0.01uF.)

I would use 120pf-220pf, probably no higher.

c) "Increase C6 (0.01uF) to allow full range response from mini booster". Would I be OK putting a 0.022 in there instead?

Yes.

[Al Heeley]

Many thanks Aron. I've put the circuit together but there's something wrong - got a TL072 in the end but I'll start debugging now.