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700B submerged in 6” of water....hmmmmm...
- Thread starter Geegz
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You wouldn’t have the meter scale- it’s part of the series II front sub panels. If you could cannibalize an old one, electronically it should still work. Another connection to the AC at the rectifier. There’s also a switch on the series II front to knock the meters down -20db. The scale on the 400/II is different, of course...
If a 700 or 700B series 1 (or for that matter a 400 series 1) transformer is to be used with LED style VU meters (i.e. Cyclons) typically you would need to provide it with 12 volts AC as the series 1 amps came with a 6V secondary for powering the incandescent bulbs. I happen to have a prototype Phase Linear series II amplifier when Phase Linear hadn't received the new series II transformers yet. So they installed a 12.6V CT 1.2A transformer inside the amp on the side wall near the outputs. NOTE: If you install a DC protection relay there may not be enough clearance to place the transformer there.
It has been a while so my memory is a bit fuzzy on the following......
So on Phase Linear 700 series amplifiers, instead of running the 120V leads all the way up to bridge rectifier you might run one lead to closest thermal cutout switch and the other lead to the accessory AC (a.k.a fan) outlet. Another option might well be both leads to the AC accessory outlet. However some of the amps had the AC accessory outlet switched and some others did not. In which case the transformer would be on all the time. Close examination of the wiring inside the amplifier should be observed in order to ensure that the transformer only comes on when the power switch is turned on. You may also want to place a low value fuse (i.e. 1A) in-line with the transformer to provide some additional protection.
I have found some 12.6V CT 1.2A Radio Shack transformers that are the same physical size as the one I have in the prototype amp. The Radio Shack catalog number is 273-1352. They can be found on ebay on occasion. https://www.ebay.com/itm/264400468903
By the way, I would love to find someone that makes a LED VU meter display that runs on 6 volts. If my memory serves me correct, the lowest I've ever found ran on 9 volts?
Ed
It has been a while so my memory is a bit fuzzy on the following......
So on Phase Linear 700 series amplifiers, instead of running the 120V leads all the way up to bridge rectifier you might run one lead to closest thermal cutout switch and the other lead to the accessory AC (a.k.a fan) outlet. Another option might well be both leads to the AC accessory outlet. However some of the amps had the AC accessory outlet switched and some others did not. In which case the transformer would be on all the time. Close examination of the wiring inside the amplifier should be observed in order to ensure that the transformer only comes on when the power switch is turned on. You may also want to place a low value fuse (i.e. 1A) in-line with the transformer to provide some additional protection.
I have found some 12.6V CT 1.2A Radio Shack transformers that are the same physical size as the one I have in the prototype amp. The Radio Shack catalog number is 273-1352. They can be found on ebay on occasion. https://www.ebay.com/itm/264400468903
By the way, I would love to find someone that makes a LED VU meter display that runs on 6 volts. If my memory serves me correct, the lowest I've ever found ran on 9 volts?
Ed
Last edited:
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
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
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
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
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