[R-390] Audio Signal Generator question

Thu, 29 Aug 2002 21:37:51 -0500

Well, things are slow here, so I dug out the HP manuals for the AB and CB.
The earliest is a 400B, tubes 6J7, 6F6, 6F5, 6V6 and 5Y3, Wein bridge with
lamp bulb regulator, 400 VDC, not available in 1960.

The AB has 6SJ7, 6K6, 6SN7, (2) 6K6 PP and a 5Y3, 250 VDC. Rated 1 watt
into 600 ohms (25 VRMS), range 20 to 40,000 CPS, 1 % distortion 30 to 20K.
Cabinet and rack mounting, good for measuring speaker impedance without an
additional amplifier, price $120 in 1960.

The CD has a balanced Wein bridge and amplifier, tubes 2 6SH7, 2 6AU5 and a
5AR4, 190 VDC. Range 5 to 600,000 CPS, distortion less than 0.5% below 500
kc, output 160 mW (10 V) into 600 ohms, price $150 in 1960.

In short, the AB provides power in the audio range. The CD provides a range
wider than audio at less power.

HP held the patent for Wein bridge oscillators regulated by lamp bulbs. It
provided the best signal. Others had to go with Twin T, etc.

I'd snap the AB on EB if I was in a snapping position.

Bill Hawkins

-----Original Message-----
From: [email protected] [mailto:[email protected]]On
Behalf Of Scott, Barry (Clyde B)
Sent: Thursday, August 29, 2002 8:54 AM
To: R390 (E-mail)
Subject: [R-390] Audio Signal Generator question

An HP200CD followed me home from the local hamfest recently.  I figured it
was worth $15 since it was working (plus it matches my HP410B).  It is a
200CD model.  Last night someone was advertising a 200AB on Ebay (a very
nice-looking one at that).  Is the CD a later version of the AB?  Is that
only difference?  Anyone?

Thanks,

Barry(III?) - N4BUQ

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