M.Hammer's Roseyray problem... HELP!

[stand]

Hi!

I finished Mark Hammer's "Roseyray" and I'd say that it really promises very good sound, but... (there is always some "but") . When I use "tone" pot to hear just sound of the first pedal stage (only first amp of dual op-amp) I've got light overdrive which lacks high frequencies and which probably would sound much better with some decent guitar amp but I believe that it's something I should expect from such design. But, when I start to turn this pot to the other extreme sound becomes lighter, with less distortion until I get almost to the other end of "pot scale". Then I can hear distortion with buzzing sound in background which is also too bassy (lacks high freq.). But, when I get to the last 5mm of that pot scale instead of "double distorted" sound (because there I should get sound of the first stage distorted by the second amp stage) I've got terrible "RRRRRR" motorboat sound which drives me crazy  . Apart from that distorted sound that I've got is great, powerful and with loooong sustain, which I like, but motorboat sound kills its sustain and it's almost unplayable this way. Otherwise pedal is dead silent, which is great!

I used the last Roseyray schematic that I found with added pair of 1uF capacitors that someone (maybe even Mark himself) proposed as 'cure' for this motorboat sound problem. I must add that I didn't have proper linear 250k pot for tone pot (which is here to adjust sound between the first and both distortion stages) so I used some 380k log pot. Does it really matter regarding this boring motorboat sound?  I'd buy proper linear pot but at this "testing level" I decided to go with pot that I already have. Other pots are regular, as schematic says.

I must say that I don't use normal guitar amp but mixer/slave/hifi speakers setup.

Finally, here are my questions:
1) Does anyone here know how can I get rid of this dreadful motorboat sound?
2) Why it appears?
3) What should I do to get  more high/less bass in all tone-pot positions except in extreme position where pedal starts to roaring (but sound IS good, with enough low and high frequencies)?

Thanks in advance for your help...

Dejan S