Stand-alone Tektronix Differential Amplifier Plug-ins & Power Supply

[nevetslab]

One thought I had on the subject for a suitable Differential Amplifier (for use with P6055 Differential Probes) for use with a standard fixed input channel scope, was using a vintage well-designed Tektronix Plug-in & matching power supply from their older generation instruments. In this case, the Power Supply is a Type 132 Single-slot unit having differential outputs, and either a Tektronix Type W Differential Comparator Plug-in or a Type 1A7A High Gain Differential Plug-in.



tek_132_1968_catalog.pdf

The Type W plugin installed in the Type 132 Power Supply has a bandwidth of around 14MHz, while the Type 1A7A is limited to 1MHz. The Input sensitivity range on the Type W is 1mV thru 50V/Div, while the sensitivity range on the Type 1A7A is 10uV thru 10V/Div, with an adjustable HP/LP Filter (6dB/Oct)

The Type W is vacuum tube based, while the 1A7A is discrete solid state, with this circuit being the foundation of numerous later generation plugins for the 5000 series & 7000 series scopes. I've kept my Type 132 Power Supply, along with a Type 127 2-slot Power Supply, and my Type O Operational Amp plugin, Type W Differential Comparator Plugin, Type T Time Base Plugin, Type 1A7A Hi Gain Differential Plugin and a Type E Differential Plugin.

I also came across a blank Plug-in in this form factor for building whatever I want, running off a well-designed power supply & output amplifier circuit of the Type 132 Power Supply. Will I ever get around to that, such as a tube bass preamp or microphone preamp? Guess that depends if I survive the Pandemic at this point.

NOTE: I was about to post a followup thread with attachments of the Operators/Service manuals for both plugin's and Power Supply, but then found their file size on the two high quality PDF files were enormous. If anyone is interested in any of those, they can PM me, with their email address so I could send them that way.

[olddawg]

Back in the late 70s and early 80s there was tons of this stuff available surplus left over from NASA ending the Apollo Program. I had an absolutely giant scope on its rolling caddy with drawers full of probes that accepted that module and others. Looked really cool but was a boat anchor with more modern equipment available. Dozens of tubes. You could heat a room with it. I forget the model number.

[nevetslab]

Back in the late 70s and early 80s there was tons of this stuff available surplus left over from NASA ending the Apollo Program. I had an absolutely giant scope on its rolling caddy with drawers full of probes that accepted that module and others. Looked really cool but was a boat anchor with more modern equipment available. Dozens of tubes. You could heat a room with it. I forget the model number.

That sounds like a 551 Dual Beam scope, with the separate power supply unit. Or maybe the 556. I had a 547 with a 1A4 4-ch plugin, along with these differential amps I still have kept. Sold the 547 decades ago. Not so much of an all-tube scope, as the 547 and 556 were hybrid designs. Large, for sure. I still marvel at their construction quality, and their exacting in-line solder joint connections in the air around those beautiful ceramic component terminal 'strips'.

[Helmholtz]

Something like this (my old 547, saved from the trash bin about 20 years ago including some 10 more plug-ins)?

[olddawg]

Mine was bigger and would accept 2 modules in the main frame and 2 in the caddy. A real monster. I think this one just keeps a second module powered on and ready in the caddy.

[Helmholtz]

I think this one just keeps a second module powered on and ready in the caddy.

It's 2 unpowered modules (a 4 channel plug-in and a differential amp) in the caddy.

[olddawg]

It's 2 unpowered modules (a 4 channel plug-in and a differential amp) in the caddy.

I think those 4 channel and diff modules were pretty common. I had those as well.

[nevetslab]

Tek Type 127 2-Channel Powered Mainframe?

Mine was bigger and would accept 2 modules in the main frame and 2 in the caddy. A real monster. I think this one just keeps a second module powered on and ready in the caddy.

Sounds like you had one of these in your system below the 551 or 556 scope, which had two slots on the scope mainframe (Time Base Type T & Vertical Amp Plugin).



tek_127_1968_catalog.pdf

My tunnel diode in the 547 Triggering system finally failed, and I never did track down a replacement to restore it. Sold off the 547 & 1A4 plugin and upgraded to 7000 series scopes, which had just flooded the market when the aerospace industry upgraded and unloaded all of the 7000 series scopes/plugins. I had two of the 127 supplies, gutted one for parts in 2015 when I moved, and the other one should still be in my lockers someplace. Kept a Type T, Type E, Type O Operational Amp, Type W & the Type 1A7A, which I see in Helmholtz spare plugin caddy on the scope cart.