Akashic Guitar effects circuit lookup
DRIVETONEACCENTVOLUME

Enclosure not stated · 4 knobs

Tagboard Effects

Shin's Music Dumbloid StandardVerified

Based on the Shin's Music Dumbloid Standard

Category
Overdrive
Controls
Drive · Tone · Accent · Volume
Build
Vero· 19×13· 17 cuts, 4 links
Layout
Verified · Tagboard Effects marks it as built and working
Tags
Overdrive

From the post

Latest $600 TGP favourite and as expected it's money for old rope. The Screamerloid is probably the correct name, and by some strange coincidence that sounds like painful hemorrhoids. Thanks to Eisy on FSB for the schematic.

Out of the 231 overdrive layouts currently on this blog there is a pretty high proportion that are extremely close to the Tubescreamer (some are basically identical) and this is definitely one that is very close. But I also think there is enough differences to make this an interesting build, and there's no doubt this has quite a few fans so something must be working right here. 95% of it is a Tubescreamer, but the notable differences is there are no clipping diodes in the feedback loop of the first opamp stage, there is a single LED being used for aymmetrical clipping in the feedback loop of the second stage, and the Accent control is an added control for the second opamp stage which will alter the frequency response, and I think possibly the gain of the stage too. Those changes are enough to make this unlikely to sound just like a Tubescreamer even if the topology is extremely close in many other areas, and so this is one that I will definitely be building just to see how those sort of changes make this differ from what I would have expected from this circuit.

Still not worth anything like $600 though :o)

Expected cringeworthy marketing spiel:

One of the most iconic and sought after amps in history… in a pedal! All D*mble amps are different in tone but the main characteristics that set these amps apart are the open uncompressed cleans and the evenly compressed overdrive. These pedals are very limited. Shin’s music in Tokyo Japan is the builder and he knows tone. This does not sound like a pedal…it sounds and reacts like an amp. Many pedals claim this feat but few can back it up…The Dumbloid does!

Schematic

This is a board layout, a drawing of where each part goes, and the post may link the schematic it was drawn from. Open the layout at Tagboard Effects. No KiCad fragment has been drawn for this circuit yet.

Parts list 26 rows

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RefValueNormalizedTypeNotes
Resistors 8
×810K10kread from the layout by eye
×31K1kread from the layout by eye
×2100R100read from the layout by eye
×1220R220read from the layout by eye
×11K51.5kread from the layout by eye
×1100K100kread from the layout by eye
×1150K150kread from the layout by eye
×11M1Mread from the layout by eye
Capacitors 10
×3220n220nread from the layout by eye
×1470n470nread from the layout by eye
×1100n100nread from the layout by eye
×11u1ufilm; read from the layout by eye
×182p82pread from the layout by eye
×1100p100pread from the layout by eye
×12u22.2uelectrolytic; read from the layout by eye
×122u22uelectrolytic; read from the layout by eye
×147u47uelectrolytic; read from the layout by eye
×1100u100uelectrolytic; read from the layout by eye
Transistors 2
Q1BC548BBC548Bread from the layout by eye
Q2BC548BBC548Bread from the layout by eye
ICs 1
×1OPA2134OPA2134read from the layout by eye
Potentiometers 4
DriveA1MA1MPotentiometerwires labelled Gain; read from the layout by eye
ToneB20KB20kPotentiometerread from the layout by eye
AccentB25KB25kPotentiometerread from the layout by eye
VolumeA100KA100kPotentiometerread from the layout by eye
LEDs 1
D13mm red LED3MM RED LEDon board; read from the layout by eye