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Mcintosh MC3500 Service Manual
Fender and Magnatone Vibrato/Tremelo Circuits
Hammond B3 Preamp Circuit
When Seattle switched to 7-character dialing
Recordings to Ponder
Ampex Stuff

McIntosh MC3500 Service Manual.

These are high-quality scans from my original copy (which is not a copy) of the service manual. There was not much effort expended at minimizing file size. There was effort expended in preserving the original print quality.

The pages are presented in the same order as they are in the printed document. This is the entire document. If you want the entire manual, in a single file, then download the last item.

Manual Cover
Specifications
Power Supply Schematic
Meter Section PCB
Meter Section Schematic
Amplifier PCB
MC3500 Amplifier Schematic (3MB)
Parts List, page 1
Parts List, page 2
Entire Manual, all pages (20MB)

n.b. There is no schematic for the impedance selector switch.

Guitar Amp Vibrato/Tremelo Circuits

Fender Bandmaster 6G7 uses Leo's patented bass/treble tremelo circuit. Audio is highpassed and lowpassed, each into a separate triode. the Tremelo oscillator is phase split and applied as a push-pull signal to the highpass and lowpass triodes. These stages are mixed, and this cancels the tremelo oscillator signal.
Gibson GA40 schematic. This looks suitably strange, and I haven't tried to figure it out (yet).
Magnatone 450A amplifier. The Magnatone amps had a true vibrato circuit that actually created FM. Other amps of the day actually created AM with their tremelo circuits, even if they were marked Vibrato. The part of the circuit that does the magic is located where the Varistors are (somewhat different than the MOVs found in power strips today).

Hammond B3 Preamp Circuit

B3 Preamp
B3-C3 Percussion Circuit Description

When Seattle Got 7-Character Telephone Numbers

We made the big switch to 7-character (it wasn't all digits back then) in 1958. I was there for it, and remember it even now, 50+ years later. It comes up now and again, so I formalized my memory of the event.

1958 Seattle Conversion Table Cover of 1958 Telephone Directory

Recording(s) to ponder

Shalom Aleichem/Sei Yona - Shawn Weaver

This text will be replaced by the single-file flash music player.

Download mp3, 3.2mb

This is my friend Shawn Weaver's work. It's all him here, playing and singing everything. The majority of the instruments were miked in stereo (i.e. 2 mikes), and I attempted to maintain that "stereoness" thru the mixing process. The bass, sax and vocal tracks are most likely mono tracks but the thumb pianos and percussion are stereo. Since there were only 5 instruments (two thumb pianos, percussion, soprano sax and vocal), I wanted more spatial complexity than 5 mono tracks that were panpotted into place would have given. My goal was to get a bit more air around the instruments.

I don't remember what mikes were used, might have been B&K (DPA), could have been KM-84s or maybe C-451s or even Audio Technica 4051s. Recorded on a Sony 3324.

Ampex Stuff

The Ampex Stuff has moved to its own page: www.uneeda-audio.com/ampex/

Last modified 04/10/2011. 20:59:47