Fryette Effects - SAS EF86 Overdrive  [traced]

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.
User avatar
energo70
Information
Posts: 1
Joined: 25 Dec 2014, 20:55

Post by energo70 »

I have one too and the pedal sounds great if I cut down the treble on my DRRI head otherwise it's just too harsh but then
my other pedals don't sound good. Any suggestions which capacitors to change... to tame down the harshness.
Anyone knows what to do with volume issue too? Thanks!

User avatar
Liquids
Breadboard Brother
Information
Posts: 143
Joined: 24 Apr 2009, 19:29
my favorite amplifier: Ampeg V4!!!!
Location: USA
Has thanked: 20 times
Been thanked: 27 times

Post by Liquids »

energo70 wrote:I have one too and the pedal sounds great if I cut down the treble on my DRRI head otherwise it's just too harsh but then
my other pedals don't sound good. Any suggestions which capacitors to change... to tame down the harshness.
Anyone knows what to do with volume issue too? Thanks!
From the schematic I saw on page 2, the easiest way to reduce treble post-clipping MAY be adding a capacitor wired from one of the outside lugs of the volume pot to the other outside lug (so the treble cut will not be interactive with the volume setting). I haven't scrutinized the layout of the pedal to see if theres a better way, but that should work in general. The size of the cap will vary with your taste. It's hard to calculate it unless someone can estimate the output impedance of the tube gain stage is, other than it being no larger than 100k...a very wide range of possibilities beyond that.

User avatar
ppluis0
Diode Debunker
Information
Posts: 915
Joined: 14 Jul 2010, 18:33
Location: Argentina
Has thanked: 127 times
Been thanked: 299 times

Post by ppluis0 »

energo70 wrote:Anyone knows what to do with volume issue too? Thanks!
You should put a resistor in series with the "hot" lug of the volume pot ( the outer lug that isn't connected to ground), to attenuate the level of signal and make that potentiometer more useable. I guess that a value of 100K is a starting point.

Also, to reduce the harsh, a forum member suggest to remove the couple of back to back diodes placed at the output of the op amp.

Look at the images that appears in the first post of this thread to locate a pair of tiny blue diodes, and merely lift one terminal of each one instead to remove completely -if you after decide to solder again- and tell us what you hear.

Be aware to unplug the power pack of this pedal and wait several minutes to allow discharge the energy of the supply condensers to avoid an electric shock, prior to work inside this unit... :secret:

Keep us posted about this mod. 8)

Cheers,
Josè

Post Reply