small special 100

[jujudubluz]

hey guys, i'm gathering informations about that one...
would you be interessed in a project, i started a layout and can share...

Julien

[tictac]

By all means...

Lay it on me... (us)

TT

[KT66]

Here's a few pics of one from that Ebay auction a couple of years ago :

[talbany]

Ryan
Cool man!!.. Thanks for posting..

Tony

[jujudubluz]

got those pics too, i'm in the process of putting together a nice layout, will post it

Juju

[stevlech]

Looks like second generation ODS without the OD. Thank you for sharing.

[topbrent]

Where is the "mid" cap in the tonestack?

[Colossal]

"She may not look like much kid, but she's got it where it counts. She'll make point five past light speed"
--- Han Solo

[glasman]

Where is the "mid" cap in the tonestack?

Probably a Skyliner configuration without the mid circuit....

[jon]

I'm very interested. I know the chassis dimensions are 17X8X3, from this article.

Mid-Seventies Dumble Small Special 100

This amp is basically a 100 watt Overdrive Special minus the Overdrive. This circuit was also used as a bass amp. It has very full headroom and wonderful sparkly-clean tones. The level control is a second volume inserted later in the circuit (but before the phase inverter), so it allows for subtle adjustments to the gain characteristics of the preamp section. It's not about crunchy overdrive.

The cabinet is not original. It was recently custom-made; blueprinted from a 50 watt Small Special of exactly the same era. It is constructed of 3/4" baltic birch plywood and uses solid aluminum bar stock for the trim.

The rear nameplate is also not original. It was custom fabricated from gold anodized aluminum to match an original, but it does not have the original serial number. The chassis was partially disassembled when found and the rear panel, power chord, and tube shields for V1 & V2 were missing. The bat for the ground switch was also broken off. This switch can still be operated with a small screwdriver, and was left as-is.

Inside the chassis, the 5 power supply filter capacitors, were found to be non-original and were not the right size to fit the board they are mounted on. They were properly replaced with fresh Sprague Atoms of the correct size and value. All other components are original as found, including the electrolytics used for cathode bypass and bias power supply.

Cabinet dimensions: 18 3/4" wide, 10" high, 9 3/4"deep
Chassis dimensions: 17" wide, 3" high (not including tubes & transformers), 8" deep

Tubes: V1 vintage Mullard 12AX7; V2 vintage Sylvania 12AX7; V3-V6 6L6 (new, matched quad) by Tube Amp Doctor

Transformers:
Note, all are Fender OEM iron as used in Twin Reverb, Showman, & Dual Showman.
Power Transformer 022756, 606 2273, CSA 827 (22nd week of 1973)
Output Transformer 022889, 606-3-35 (35th week of 1973)
Choke 022699, 606-3-48 (48th week of 1973)

Potentiometers (date codes range from 1970 to 1973):
Volume 1377014; Treble 137271; Bass 1377227; Level 1377315; Bias Adjust 13771__ (last 2 digits obscured)

[talbany]

Tonestack could be a variant of a Baxandall if it was built for Bass or intended to be clean
(Baxandall uses James config on bass pot no mid and 100k slppe)
Tony

[ER]

I would guess it's very similar to this one;
http://www.webphix.com/schematic%20heav ... asspre.pdf
Two inputs (no FET), treble, bass, bright, deep, git/mic. I suspect whenever a dumble was built "more like a bass amp" part of that means 25uF cathode bypass caps.
The power supply and power amp are on there as well under "60's Dumble".

-E