HAO Sole Pressure

[johnk]

I just drew up a vero and built the HAO Sole Pressure distortion pedal and it sounds great. Brett Kingman (who I respect greatly) said that it's of the best pedals that emulates a '59 tweed bassman and I agree with him that it does. funny thing is, the circuit is extremely similar to an MXR distortion plus, but HAO used only half of a TL072 instead of a single LM741 opamp as found in a D+, and made quite a few other changes to the circuit.

anyway, here's the VERIFIED vero for it:

[Surgeon]

Awesome! thanks a lot for sharing John!

[johnk]

finally got it mounted in its enclosure. I really dig this one and it also makes a great bass overdrive.

[IvIark]

Nice one, thanks John, and your build looks even more spookily like the original than usual to me!
I've got an original Sole Pressure and agree it's a great sounding overdrive, and something a bit different.

[cylens]

Thanks John,

will definitely try this one. out of curiosity, did you have a chance to compare it to a Catalinbread Formula 5F6 (If I get it right, they're supposed to emulate the same amp)?

correct me if I'm wrong, but round LEDs will do the trick, right?

[cylens]

OK, finally build this one too, and it sound great. It's not boxed yet and squeals quite loud, hope it will stop once boxed!

[cylens]

finally boxed it and it stopped squealing!

[josepqr]

hello,

My name is Josep, I'm from Spain (Europe)

a question,

3 things do not quite understand;

1) - The nasal polarized capacitor 47u, 47u it really is? I think demsiado for Non polarized and also in the photo of your finished board not see such a large capacitor, do you could check?

2) -the drive potentiometer is C500K,. and I ask; What do you mean C500K? I only know 2 types of potentiometers A500k and B500K.

C500K does that mean?

3rd) .- Les red squares should be square mandatory ??? or may be standard round?


Do you have the address schema and actual values of the components for the sole HAO Pressure?

I'm trying fabricarme one but here in Europe there is very little information on this magnificent pedal.s very little information on this magnificent pedal.

[dbat69]

Hello Josep

I haven't built this one but will try and answer 2 questions

1  It looks like the photo shows two capacitors in parallel to get (near to) the 47u.  From the comments on the Vero layout - yes it is non-polarised

2  C500k  is a reverse logarithmic pot.  THis has the curve going in the opposite direction so the control doesn't just happen at only a small part of the range.

3  THe best way is to socket the LEDs and try them

[josepqr]

Hello dbat69,

thanks for the reply!

although in the photograph have two capacitors in parallel, but do not think are that capacity, basically by the size of the capacitors themselves you see in the picture. (I think they are smaller, may have to be 47p ????)

as far as I know potentiometers reverse logarithmic range as "C".
potentiometers are:

A: logarithmic
B: linear
F: antilogarithmic

these are the only ones I know, anyway, I'll put one of B500K.

thanks for your answer, see if someone is able to provide real circuit diagram.

Thank you very much!

[dbat69]

Hi Josep

reverse log pot is the same as antilog pot

It is unlikely that there would be any confusion with a 47p - that will almost certainly be non-polar.  SO I would deduce that it is a 47u cap

[johnk]

schematic:

[johnk]

BTW, I used two 1uf caps in parallel in mine to get 2uf for the non polarized 47u cap on the drive pot since anything larger than 2uf makes no difference in the sound.

[dbat69]

Thanks John for putting me right

[Jopn]

josepqr wrote

...
although in the photograph have two capacitors in parallel, but do not think are that capacity, basically by the size of the capacitors themselves you see in the picture. (I think they are smaller, may have to be 47p ????)
...

Those are monolithic ceramic capacitors which are quite small for their capacitance.  

[josepqr]

many, many, thank you very much Jhon

You've cleared my doubts totally !!

thanks for the scheme.

2 capacitors can be 2UF, but it was impossible (physically) that were 47uf.

Now I just have to find a solution to C500K (NOT have !!!!!)

[josepqr]

a question ;

to do a little brighter ( just a little ) the brilliant channel
Should we change the value of capacitor C1 ?
What value ?

thanks

[negativefx]

A B500K or A500K will work.  The sweep just won't be the same.  In this particular case, I recommend the B500K rather than A500K if possible.  Anti-log pots have the majority of the sweep on the low end whereas the log pots have the majority of the sweep on the high end.  If you use a lin B500K, it just means that you'll find most of the gain up on the high end of the knob.  The first half of the sweep won't do much.  It's a sensitivity thing... minor adjustments on the high end will be more significant than the low end.  Drive at 0 or drive at 10 will sound no different regardless of which taper you use.  It's the transition from 0 to 10 that will differ.

This graph describes it well:  http://sound.westhost.com/pots-f4.gif
Full explanation here: http://sound.westhost.com/pots.htm

[josepqr]

negativefx thanks !!

I ua order Ebay one C500K. (I hope I come shortly).

On the question before;

Any idea how to make a little more Bright channel? (... Just a little)

[rocket88]

If you want to make it brighter change the values of the caps connected to the switch, 1nF and 2.2nF. The switch lets you choose between different output caps. The higher the value the more bass comes through and warmer it will sound, conversely the lower the value the less bass makes it through and it will sound brighter. Replace both caps with sockets and try some different values to find something you want. Then you can either leave it in the socket or remove the socket and solder the wanted cap in place.