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Dumble Overdrive Reverb Special (100 watt) Guitar Amplifier - 1978
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Dumble Overdrive Reverb Special (100 watt) Guitar Amplifier - 1978
Price: US $35050.00
Antique Amplification has recently completed the full restoration of an impossibly scarce 1978 Dumble Overdrive Reverb Special (100 watt) for an owner that I represent. I have requested the assistance of Antique Amplification in offering this fine specimen of Alexander “Howard” Dumble’s early work for sale. The ODRSis considered by many of the Dumble amplifier aficionados to be the \'Holy Grail\'of all Dumble amplifiers. The total production of this model is unknown but has been estimated to be less than fifteen total units. The highest previously known serial number for an ODRS is #0078. This amp has a serial number in the #008X’s making it very likely the last of its kind produced by Mr. Dumble. The current owner is the original owner, a 67 year professional guitarist hailing from Ontario, Canada.

Amp SpecificationsGeneral:
Make: Dumble
Year of Mfg: 1978
Model: OD-100WR, Overdrive Reverb Special (OD Post Reverb)
Serial Number: 008X
Format: HeadCore Amplifier Component Specifications
Power Transformer: Fender (Woodward/Schumacher) L022756
Choke: Fender (Woodward/Schumacher) 022699
Reverb Transformer: Fender (Woodward/Schumacher) 022921
Low Voltage Transformer: Calrad
Output Transformer: Fender (Woodward/Schumacher) 022889
Switching Relay: Calrad 12VDC/ 250 ohm/ 50 MA
OT secondary impedance: 4 ohms (Single Tap)Face Panel Features:
Inputs Jacks: FET & Normal, (Signal to V1A)
Volume (Controls signal level to V1B)
Tone stack: Passive Treble, Middle, Bass,
Reverb Send: Signal to tank (V2A, V3A, V3B)
Reverb Return: Mix Signal to dry signal (V2B, V4A)
Overdrive: (Controls signal level to V5B)
Level: (Global Master Volume to V6)
3 x Slider Switches: Bright/Deep/Guitar-Microphone
1 x Slider Switch: Pedal/Manual
1 x Slider Switch: Mid (Presence)Back Panel Features:
A/C Accessory Outlet
Reverse Polarity for chassis ground toggle switch
Fuse: 3AMP Slo-Blo
Mains toggle switch (Power On)
Standby toggle switch
Speaker Jacks 2 (4 ohms total)
Pre-ampoutput jack
Foot Pedal (XLR)Tube Compliment:
V1 =12AX7, 1st and 2nd gain stages (clean channel)
V2 = 12AX7, Reverb
V3 = 12AX7, Reverb
V4A = 12AX7, Reverb
V4B = 12AX7, 3rd gain stage (clean channel)
V5 = 12AX7, 4th & 5th gain stages, post relay (Overdrive)
V6 =12AT7, Polarity Splitter
V7, V8, V9 & V10 = 6L6GC Power TubesPerformance & Technical Specifications
Power (Rated) = 100 Watts
Power (Actual) = 90.25Watts RMS(19 VAC into 4 ohms)
THD (Actual) = 4.69% @ 90. 25 Watts RMS
Pre-Amp + Power Section S/N Ratio (Actual) = -39dB
Power Section S/N Ratio (Actual) = -46.5dB
B+ = 432VDC @ idle
Bias = Fixed, -44VDCThe amplifier is currently located, and is being sold from Southern California.*Note*
Antique Amplification will not provide schematics, circuit layout, circuit details, component values or any images describing or depicting the internal features of this amplifier.

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