In 1982 Vorhis and Jung collaborated on a Dynaco PAS Modification "The Last PAS" (although you could have fooled me, as there have been umpteen since.) The Regulated supply was designed by Walt Jung and is the same as the one used in a Marantz 7 mod.
I was going to burn a few boards, but if there is sufficient interest I can get the unit cost down to around $6 or $7.
Here's the schematic:
This is a drawing
email me jack@tech-diy.com if interested.
I was going to burn a few boards, but if there is sufficient interest I can get the unit cost down to around $6 or $7.
Here's the schematic:
An externally hosted image should be here but it was not working when we last tested it.
This is a drawing
An externally hosted image should be here but it was not working when we last tested it.
email me jack@tech-diy.com if interested.
an alternative?
Jack,
I'm sure the 1982 circuit will work fine but its a bit complicated due to the fact the the regulator chip wasn't really designed to handle high voltages. ICs have made a lot of progress and there are some high voltage regulators that allow this circuit to be a bit simpler. Here are links to an article and datasheet using the Supertex LR8 high voltage regulator to good effect.
---Gary
http://www.antiquewireless.org/otb/resto0504.htm
http://www.supertex.com/pdf/datasheets/LR8.pdf
Jack,
I'm sure the 1982 circuit will work fine but its a bit complicated due to the fact the the regulator chip wasn't really designed to handle high voltages. ICs have made a lot of progress and there are some high voltage regulators that allow this circuit to be a bit simpler. Here are links to an article and datasheet using the Supertex LR8 high voltage regulator to good effect.
---Gary
http://www.antiquewireless.org/otb/resto0504.htm
http://www.supertex.com/pdf/datasheets/LR8.pdf
Re: an alternative?
When you use an IC like the LR8 you multiply the noise of its voltage reference by the gain, although I will have to determine empirically whether the zener string with the filter is better or inferior to the setup shown. This circuit has the distinct advantage that the zener reference is driven from the regulated output -- similar to the way that Jung derived the reference for the Super Regulator.
I have received a few notes for some modifications -- the big polypropylenes should probably have L of 27.5, 31.5 and 37.5 mm, some have requested big pads for a choke , full wave bridge, etc. One thing I might consider is an option for a different transistor, but the MJE3439 is a nice TO-225 -- mbe TO-220 as well (which will require some gymnastics.) I haven't sent the boards out, won't do so for a few days until I hear back.
GaryB said:
When you use an IC like the LR8 you multiply the noise of its voltage reference by the gain, although I will have to determine empirically whether the zener string with the filter is better or inferior to the setup shown. This circuit has the distinct advantage that the zener reference is driven from the regulated output -- similar to the way that Jung derived the reference for the Super Regulator.
I have received a few notes for some modifications -- the big polypropylenes should probably have L of 27.5, 31.5 and 37.5 mm, some have requested big pads for a choke , full wave bridge, etc. One thing I might consider is an option for a different transistor, but the MJE3439 is a nice TO-225 -- mbe TO-220 as well (which will require some gymnastics.) I haven't sent the boards out, won't do so for a few days until I hear back.
some changes -- I worked the board around so that it would fit without major gymnastics into the PAS cabinet -- (note -- the silk isn't dropped in yet). The blue vertical line is a 1/8" saw mark so that the boards can be split. The size of the eyelets were increased pretty substantially. I also allowed for the possibility of employing a full wave bridge.
here's how I propose the two boards will fit into the PAS:
An externally hosted image should be here but it was not working when we last tested it.
here's how I propose the two boards will fit into the PAS:
An externally hosted image should be here but it was not working when we last tested it.
Partially, but I've also found putting a couple of ohms in series with output caps can be useful for stabilty.
For my own applications, I'll probably end up using a bypassed resistor in place of the zener string (i.e., use this as a Maida-type reg), but that's my worry, not the board designer's.
For my own applications, I'll probably end up using a bypassed resistor in place of the zener string (i.e., use this as a Maida-type reg), but that's my worry, not the board designer's.
Here's another 3D view -- so that the size of the eyelet pads can be seen -- also with SY's "Zero-Ohm" R0411R12 resistors.
An externally hosted image should be here but it was not working when we last tested it.
Here's the schema to satisfy SY, (and I received an email from someone who wanted the option of FWB)
-- some of the WIMA caps are a bit difficult to get (but I was able to purchase some MKP4-4.7/400's). There is now enough room on the board to heat sink both the MJE3439 and LM317. It will take a few weeks to get the boards back, so don't be impatient.
-- some of the WIMA caps are a bit difficult to get (but I was able to purchase some MKP4-4.7/400's). There is now enough room on the board to heat sink both the MJE3439 and LM317. It will take a few weeks to get the boards back, so don't be impatient.
An externally hosted image should be here but it was not working when we last tested it.
Here's the first test run on the regulator supply -- input is 400 VDC from a regulated supply -- the Heath IP-17 -- load was about 6 mA.
An externally hosted image should be here but it was not working when we last tested it.
OK, figure 4 weeks for the boards -- late November -- to keep the costs down -- 2 layers with silkscreen. The cost is $6 (which includes PayPal fees) + $4 s/h US and Canada OR $5 s/h Europe where Global Priority Mail is available (GPM is not available to Italy, Greece, Argentina and parts of Brazil). If GPM is not available I will ship via registered airmail at your expense.
After the group order I will put the remainder on my website for $12.
After the group order I will put the remainder on my website for $12.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.