How to build power supply Heathkit WA-2P Preamp Homebrew delight

A fellow contacted me with a request to build a custom power supply in support of his classic Heathkit tube HiFi system. I did not realize that there were preamps that relied on the power amp for operating voltages. After some research, I discovered that Dynaco also made earlier equipment with this limitation. They offered the PS-1, however I do not beleive that Heathkit offered a similar unit. So, I was up for the challenge. This video covers construction for the Heathkit style only. You can use this as reference to make one that fits your application. Just make sure to get the pinout configured to the amp you are using. This power box supplies approx 6VAC @ 1A and 325 VDC @ 10ma. If you need more HV current, you can upgrade the main power transformer. The Stancor I used works perfectly. If you would like an updated schematic, contact me. I will send you a .jpg. There are many ways to construct this circuit. My method may not be your choice. Bashing bounces off. So, save your hacking for another channel.

[@teddriver_6021]

D-lab Electronics. Great video. Thanks for posting. The Heathkit assembly manual spells out the power supply requirements: 6.3V AC at 1.0 amp. 300V DC at 10ma.” The 6.3V AC supplies the filaments. The 300V DC supplies the B+. The Voltage Chart, on page 32 of the manual, shows the high voltage input specified at 320V DC, which is twenty volts greater than the page 6 requirements. Applying 320V to the first section of the filter capacitor could be a problem for early WA-P2 preamps because the early versions used an electrolytic capacitor with a 300V rating. Later Heathkit WA-P2 units were supplied with capacitors with a 350V rating. Be sure to check which capacitor is in your preamplifier if you intend to power it with a voltage greater than 300V. . In my power supply designs, I set my target voltage at 320V to be consistent with the Voltage Chart.

[@hestheMaster]

Ah, grandpa and granddaughter fun! What a nice learning experience to see in action.

[@Finom1]

Emi, God Bless and Protect your wonderful family. Terry, thank you for sharing your wisdom with us.

[@n8nkqrp595]

Now that the shop Boss is back, things are gonna happen fast! Welcome back to your channel, Emi :)

[@russellhltn1396]

Looks like Snozzaramus II. Looking pretty new there.

[@rciancia]

Nice little power box... and Emi... wow Terry, she is not a little girl any more.. so cool to watch her grow.. You two make a good team !!!! Nice

[@preiter20]

Proper supervision is often necessary! Glad to see Snauzeramous fixed!

[@300poundbassman]

Kool happy 4th to you too! Nice power supply great to have your Future generation Interested in the old stuff Nice Bottom end on the music Captain Nemo Out Stay safe!!

[@userfixit]

Always some Quality work from EMI-Lab. Really enjoy your projects Bob. KQ2Q. Danielsville GA

[@milanrecordingstudios9042]

Very cool for sure. I do believe you could build anything.

[@Nirky]

Any video is enhanced when Emi makes an appearance!

[@warmsteamingpile]

She's an adorable kid!

[@scottbc31h22]

Early Hammond organs did the same thing for the preamp in the organ, with the B+ voltage being fed from the power amp in a separate cabinet. Imagine, having 120 VAC line current, audio signal and 260-300VDC all in the same cable. UL labs would have a fit. Tip: When I build a power supply, I install an indicator on each output. A NE-2 lamp with proper resistor works well for the high voltage output.

[@jimgiordano8218]

The D-Lab comedy club.

[@albertwheeler2395]

Cute assistant! I inherited a Heathkit WA-P2 Pre Amp from my dad, and I want to build this power supply, but please help a little bit. What's a "4 Henry choke?" Can you provide specs? Also where did you run that 10K resistor? I assume in series from pin out #5 of the octal socket to the choke and capacitor? Lastly, what value resistor did you use to simulate the high voltage load on the octal? I assume you put that across pins 5 to 3 (ground) on the octal? Also, couldn't you have used a grounding terminal and lock washer instead of the heavy duty soldering ? I would like to do this project, but there are a few missing pieces. Thanks.

[@johnnaighley9252]

Well, in honor of Emi, additionally a correspondent line filter should be built in, Terry... *lol*

[@georgekrabs6948]

Emi is so sharp and she makes me laugh so much

[@vicmiller7191]

Nice little supply, and yes I can see her throwing that dirt at you...lol. thanks for sharing...Vic KE8JWE

[@richysradioroom]

Climax coffee...yum.

[@tsloth1390]

Wtf Terry, I just built mine last week! 😂

[@gabet3754]

Lil cutie

[@edwardlarose7691]

Hey Terry, quick power supply question...when using serial caps to get a higher voltage rating, how do you determine the value and wattage of the balancing resistors? I know you didn't do that in this video, but I'm working on building an amp with a 360-0-360 transformer. Thanks!

[@JolicoeurAbear]

have you ever done a video showing how to take a modern acv and deflate it to vintage? like 110v to 117v?

[@TheTrueVoiceOfReason]

I'm sure Emi would have got it if you'd have said C3PO. :D

[@johnwilliamson467]

Question should not the choke be rotated 90 degrees to reduce field coupling with the transformer ?

[@tsloth1390]

Yup! Probably not a big deal but it would be better that way

[@faridkhalafpoor715]

ok

[@SwanseaTitanFan]

I can’t wait to ha e grandchildren.

[@darthbubba866]

Her Aunt probably let her stay longer because Emi was cooking breakfast for them.

[@sean-ci3tv]

why not use diodes to make a virtual earth for safety to avoid earth loops?

[@Bigjoedo66]

Heathkit you are dating yourself. LOL I build several Heathkit products

[@thisisgil7394]

Awesome video! Have a look at my account and sub if you like my content 😊

[@jackmatthews2840]

I B 1st