🚀 go-pugleaf

Bitsavers just posted a design guide for the CDC 3600 dating from
1962.  Very technical, but interesting.  Details the gory details
of all the transistors--breakdown and saturation voltages, 
current gain, gain bandwidth, collector capacitance, type,
and material.

Then it has very detailed circuit descriptions.

http://www.bitsavers.org/pdf/cdc/3x00/48bit/CDC_3600_System_Design_Handbook_Sep1962.pdf


sample text

The degree of sensitivity exhibited by a differential amplifier to potential differences between its inputs as opposed to simultaneous shifts of both inputs in the common mode is often represented by a number called the "common mode' rejection ratio", which figure for this circuit is of the order of 40,000. 
Resistors ROl and R03 are connected in series across the two inputs, as shown. This relatively low resistance is in parallel with the input impedance of the amplifie~, so that the total terminating impedance across the sense line is reduced. This has the effect of making the amplifier less 'sensitive to noise induced by the flow ~f inhibit current. 

The 4 uh inductors in the emitter circuits of Q02 and Q03 determine the high frequency roll-off of the amplifier. This inductance reduces the gain at high frequencies,' and prevents the amplifier from responding,to,noise spikes. 
The signals produced by the memory cores are received and amplified in the dbuble-ended ,fashion.' As an example of operation, assume that the 30 mv potential from th~ memory core is of a direction such that pin 4 shifts negative 15 mv and pin 5 shifts positive 15 mv from the rest state. These potentials are applied to the . bases of Q02 and Q03, causing Q02 to conduct more heavily while conduction through Q03 decreases. This action is further regulated by the constant-current S9urce th~ough Q01, so that an emitter current increase in Q02 'must be accompanied by a corres,ponding decrease in Q03. 

The results of the preceding action are such that the collector' of Q02 becomes . more positive and the collector of Q03 becomes more negative. This, in turn, cause,s transistors Q04 and Q06 to conduct less hea:,vily' while conduction through Q05 and Q07 incr~ases. The' collectors of Q04 and 'Q06 therefore ~hift approximately 1.5v in the negative direction and the, collectors of Q05 and Q07 shift a' similar . . amount iJ;l'the positive direction, so that a potential difference of 3v exists acro'ss the diode bridge.