Heathkit PS-4 Regulated Power Supply

[DrGonz78]

Just looking for general advice on what I have here... I mean in a sense I understand what this does but having trouble envisioning how to put it to use right now. I have only turned it on using a light bulb limiter and it passed the test. No shorts I guess. I was just intrigued by this power regulator and it can be mine for about $40. So, what the heck right!?! My friend came across a stash of a few old oscilloscopes and this device. They were outside under a tarp but still were in good shape!! Yikes! This thing is in great condition for it dates back to the early 60's.

So, does anyone have some good knowledge how to put this to good use? Thanks.

[nickb]

A manually operated triode curve tester c o/p to grid, B to Plate. Turn the knobs and plot Vp/Ip on paper...

[J M Fahey]

Excellent tool for a preamp designer .
Or power tube matcher. <<<<<<<<<<<<<<<<<<<< specially this
You can offer the niche service of selling 6L6 matched @-52V (old blackface standard) or graded 1/10 like MB, how's that?
Or what nickb said.

[olddawg]

It's just a regulated variable DC supply for just about anything that does not exceed its current rating. The good thing is it has an amp meter. Every bench has something like it. Most people prefer a dual supply nowadays with current limiting presets. Not a bad price if it works. Worthless if it doesn't.

[Enzo]

yes^^^

It is a bench supply for tube circuits. You have an adjustable B+ supply, an adjustable C- supply (bias), and 6.3VAC for the heaters. If you want to try some tube circuits, preamps for example, you can use this unit to power them, rather than having to build a power supply for each project.

[DrGonz78]

Okay thanks to all that replied! I was thinking this might help me on future builds as I get into designing tube preamp circuits. I will probably end up buying it but first I will test it fully to make sure it is working 100%.

[Enzo]

Like most old electronics, you probably will want to replace the filter caps.

I don't have that model, but I have several other similar units, ,some from Heathkit. I have an IP32 which looks just like yours and is darn similar, among others.

[DrGonz78]

Yeah I was thinking it would be wise to replace those old caps. Also, a question always arises to replace the 2 prong with a 3 prong AC electrical cable. The hot and neutral are fed directly into two different tubes. I am guessing one is a rectifier tube and the other is one of the 6L6, but that is going by memory. Would that be recommended to replace the AC cord?

[52 Bill]

The hot and neutral are fed directly into two different tubes. I am guessing one is a rectifier tube and the other is one of the 6L6, but that is going by memory.

The schematic shows no direct connection of the power line to any tube. They may be using unused pins on the tube sockets as tie points.

[DrGonz78]

Bill you always right on the money! I will look at it in more detail later on and confirm your point. Yeah I have looked at the schematic so I should have known that already. I see now that there is a grey wire that jumps straight up to the power Off/Standby/On switch in the front panel. That grey wire is from the tube and uses the tube pins as a tie point. So that makes total sense, but I will have to read and follow schematic to figure out more about this regulator. I guess I have questions as far as what the two transformers are really doing? Is this like a widow maker amp how it is wired from the AC lines? Is it left best with a floating ground or should I have a crack at putting a safety grounded 3-prong cable on this device?

I guess I need to study the power supply and schematic more to figure as far as if AC voltage is rectified w/ out passing through a power transformer first.

Edit: okay I see it now... The AC line splits one going to the power switch and then it goes from there to one of the power transformers... The other line goes through the fuse switch and then straight to the other transformer... Just never seen that before.

[J M Fahey]

okay I see it now...

Well, we still don't
Post that schematic.

[DrGonz78]

Hey I am not saying I do understand this device by looking at the schematic... I actually am seeing more by looking straight at actual machine... LOL

Maybe ya'll can help me read this schematic more clearly. I probably just need to look harder at it but looking at the device is more sensible than the schematic is to me at this moment.

[52 Bill]

There is no direct connection of the ac wall voltage and any part of the circuitry. One transformer is for the 6 volt filament circuits and the other transformer is for the high voltage power supply.

The power switch has a standby mode and an on mode. In standby it turns on the 6 volt ac transformer only. In on mode it then turns on the high voltage transformer as well.

[Tom Phillips]

...I am not saying I do understand this device by looking at the schematic...

If you are committed to maintaining and using the unit you may want to consider procuring a copy of the manual. Even original copies usually turn up for modest $. In addition to a nice clear copy of the schematic the Heathkit manuals included theory of operation and calibration sections.
Regards,
Tom

[DrGonz78]

Yeah thanks for all the tips and information. I think I will pursue some manuals and instructions on how to operate this regulator. It might take some time but it will hopefully be useful down the road. It will be a great learning experience too.