Roger Mayer Octavia

[JaviCAP]

Hi all,

I built yesterday eveninnga a Roger Mayer Octavia. The built has great sound, very present octave up and great fuzz.

But... (there's always a BUT), as everytime I've had to deal with darlington trannies, the note decay is very quick and sudden.

There are 3  MPSA13s and a 2N3906 in the circuit. Swappin' the MPSAs you get little if any change. The only thing that helped was dropin' in the lowest hfe 2N3906 that I have (178 hfe).  Other 2N3906 from my bag go from 200 to 480hfe.


Any suggestion to ged rid af this nasty decay?

Schematics:

http://www.pisotones.com/Octavia/imgs/EsquemaJP-corregido.gif

BR

[alex.s]

I'm happy with the way mine sustains. I built it using Harald Sabro's layout based on the schematic found on fuzzcentral, haven't actually gone through the whole thing to check it's the same you posted though..!
I recorded a little demo of it, does yours sound any similar?

[JaviCAP]

Thanks Alex,

Yes, sounds very smiliar. I used Harald's layout and just changed a pair of values (470pf swapped with a 47 one, and one of the 39k changed with a 6,8 one).

The decay I tell is not a harsh or not gradual one. Has some good sustain, when when sound is finally decayin' after 3-4 seconds get suddenly cut, and happens too if using the original values.

Will have to double check.

Thanks Alex!

[alex.s]

I haven't noticed any particularly harsh decay, but will try and ring a couple loooooong notes tomorrow :)

Decay aside, that's one sweet sounding fuzz isn't it? Love mine to bits!

[JaviCAP]

Yes, love the "synth like" tones that you can get with this effect, the gated ones, the fuzz double storm on high notes. In a few words is a great effect.

Not to be always on or play with chords, but you can get incredible solo sounds!

[JaviCAP]

Hy Alex, a few comments / questions, as I see that you were the one that requested this effect on Harald's site.

Well, I did reflow the board and this has solved the decay problem but after watching your demo and some other ones I can see a big difference with my build.

ON mi board, if you set the gain knob from 0 to 50% (12 o'clock) i just get flart and gated sounds not useful at all. From 12 o'clock onwards, you start to get really nice sounds (with neck pickup) and at the end of the sweep there's wild fuzz and octave, great!

But on your demo, and other ones, from 9 o'clock you get the sound I'm gettin' at  3 o'clock.

Changed the pot to check if my C10K pot is defective (is the only one I have right now) and soldered a lineal one.

The result is just the same. The only difference is that you get the usable tones from 3 o'clock instead of 12 o'clock.

Don't know wgat the fuck can be wrong, any ideas?

BR

[alex.s]

As the pot orientation wasn't known, I wired mine backwards, hence the weird looking settings..! :)

Haven't switched it round yet as I'll do so when installing a C10K as the linear pot leaves all the usable gain settings in the very last bit of the turn making it very hard to either dial useful tones.

Basically, don't use my demo as reference for settings as I have the incorrect taper AND it's wired backwards..! It also makes it confusing as I'm not sure when you say my pedal is set at 9 o'clock if you mean literally the position, the position it would be if it was wired correctly or if you are taking into account the wiring mistake (which isn't mentioned in the video and might cause confusion)?

It actually sounds to me as if you are getting a more useful range with the correct taper pot as my distorted sounds only come out in the last quarter, which means I don't get a lot of control on that tiny bit of range.

I haven't been able to trace a good source for a limited number of C10Ks so unless I figure out how to adapt a linear, higher value pot to do the trick (adding a resistor between two lugs) I'm stuck for the time being...!

Sorry for the confusing post, should have hit the hay a while ago...! :)

[JaviCAP]

Thanks again Alex. Yes, is a bit of a mesh with reversed pots, antilog ones and so on :P But, you describe the first half of the sweep as "clean". In my build, it's flarty and gated, not what I'd call "clean". I've donde my tests with the Les Paul, tomorrow i'll try it with the strato  to see if t the first half of the turn is of more use. If not, maybe's a good idea to get a smaller por value, a C5K or even a C1K as for my dmm measurements, the pot starts to be os use in the last 2K resistance.

Tayda offers C10K pots, and they work fine, as usual. Is the only reliable source for C pots  that I've discovered so far.

BR