700B submerged in 6” of water....hmmmmm...

[Wheel-right]

Joe,

I have half a dozen chassis with 700/700B series 1 transformers in them that I'm building from scratch along with a bunch of 700 series II front panels. Since the 700B VU meters are practically unobtanium these days I have found it easier to buy broken 400 series II amps just to get the sub-fronts and LED VU meter displays out of them. (NOTE: Those 400 series II's then will have 400 series 1 front panels and VU meters installed in them.) I've bought half a dozen or so of the aforementioned 12.6V CT transformers and installed them in these chassis along with Dale 50W 5 ohm resistors in the Zobel network. There is no room to install Don's relay.

Follow me so far?

Having a 6V LED VU meter display would eliminate the need for the 12.6V CT transformers and allow me install Don's relay board.

I also had some requests over the years to change out the 700 and 700B series 1 front panels and install a LED style display instead. The front panels need not say Phase Linear on them or the need for a sub-front. One customer send me some artwork illustrating what he wants on the front panel along with his company's name on them.

The goal here is to have one of every pc board revision either made by Phase Linear, yourself, Nick Soudas, Steve Mantz, etc installed in them.

Currently I have around dozen 700's and a dozen 400's.

I've also installed some thermal cut-out switches (normally open) that are wired in series with the AC outlet (jn Phase Linear 700 series amps) so that the fan(s) will only turn on when the amp reaches a certain temperature. In this case, I have a supply of switches originally used in Hafler amps rated at around 55 degrees C. Phase Linear used a similar approach using a fan in the D-500 (no AC outlet here though). Albeit, if my memory serves me correct, the thermal-cutout (normally open) switch in the D-500 is rated at 70 degrees C.

Ed

Just curious but does this mean the VU meters on the 700B and the 400 series I are the same size even though I know they are different styles?
Also does anyone have a picture of a 700B without the colored screens on that cover the 700B logo between the meters or even a description of how it is assembled since I've never seen one? Thanks much for any help.

 

[oldphaser]

Dang! Ed's got me beat by a long shot. No surprise.

Fred,

I had as many as 150 Phase Linear amplifiers at one time.
I only wish I had them all (and the knowledge on how to repair them) back in the late 70's/early 80's when I was a sound-man.

Ed

 

[oldphaser]

Hi Ed
Thanks for the background on your earlier comment. With a couple of resistor value tweaks the WO Cylon meters will work down to 5V. Let me know if you have interest in pursuing. The current values are scaled the way they are because the thought would be they were going into the S2 transformer scenario but that can be made to be more universal

Joe

Joe,

Good to know that your will work down to 5V.

Most of the LED meter displays I've seen use IC's which require at least 9 Volts or so.

I do have an interest in pursuing this.

Let's talk more about this after the summer season is over in a month or so.

Ed

 

[oldphaser]

I will work on my current amp count...stay tuned....

I have an interesting collection of very rare Phase Linear amplifiers including the following:
1.) Bob's 1 of 3 bridge amps built which was the first Phase Linear 700 built back in early 1970.
2.) Phase Linear 700 (Kelly DeYong) amp. Also early 1970. Has trim-pots in the protection circuit.
3.) Purple Phase Linear 700 series 1 built for Heil Sound.

I have posted pictures of Bob Carver with the bridge amp and Kelly DeYong amp. I have not posted any pictures of the Heil Sound amp.

I had at one time (3) Phase Linear 700 series 1 amps built for Bell Labs (which would do .25% THD at 100KHz at rated output). Dean has the first one. The other (2) I sold to a collector.

If the price is right, I may even consider selling off some of the aforementioned amps. Make me an offer I cannot refuse!

Ed