PROBLEM SOLVED - Since I ran everything with the dim bulb test multiple times and I knew I didn't have a dead short, I pulled the DBT and ran with the variac instead. I was able to get everything up to expected voltages (or a little hotter) on the first pass. I don't know if the bulb I was using was bad (we don't have many bulbs around so grabbed the first one I saw that looked like an incandescent, maybe it's not?) or there is something off in the wiring of my DBT, but at least my PSU is working now!
Special thanks to @ItsAllInMyHead to some helpful DMs and encouraging to check for silly errors, like using the wrong lightbulb.
Calvin
Special thanks to @ItsAllInMyHead to some helpful DMs and encouraging to check for silly errors, like using the wrong lightbulb.
Calvin
Attachments
Ok, I built the Quasimodo Bell Ringer (yayyyyy!) So now I know the value of the two small film caps and the resistor I need to parallel with the secondaries on the transformers. Where exactly on the Universal Power Supply board do I mount these components?
I do appreciate the help,
John
Attachments
Can you please point me to the Quasimodo build how to, where to get boards, BOM... Need it for Wolverine PSU build. Thanks!
In between the rectifier heatsinks... 😬
But don't fret, you can mount them to the underside of the board. What I would do is mark each position carefully underneath with a sharpie. Then install the devices. I get a little dyslexic with these types of things so I am a bit extra cautious. This will be nice because you can always change the value of the resistor in for some reason you change the transformer for a different one some day.
Another note, write the value of the resistor that you install for future reference. I sometimes write the snubber specs on the underside or in a discrete location on my transformer as well.
Search for diyaudio Simple, no math transformer snubber using Quasimodo test jig. Most of the information is in Mark Johnson's first post. There's a white paper that shows the math in the footnotes and explains how the jig shortcuts the process. There are BOMs for through hole, SMD, and el Cheapo pcbs. You can also build the jig on a breadboard. Mark Johnson, the father of Quasimodo will answer any questions you may have. Gerber files are available. I would query that forum, and ask if anyone has a spare board. Some kind soul from San Francisco sent me a through hole board and wouldn't even accept remuneration for the postage. If no one has a board, you can have an economical order quantity of them made using the Gerber files, and sell off the remainder. I bought any parts I needed from Mouser. It was easy to build and easy to use. You do need an oscilloscope. And you need to feed the board between nine and fifteen volts DC to power it.
I hope I answered your questions.
Cheers,
John
Ok Mike, I guess I'll be able to fit the caps in there somewhere. There are two audio grade 500 VA Toroidy transformers each with its own power supply going into this Wolverine amplifier. I think i's a good idea to note the value of the snubbers, but honestly, if I survive this build I hope I never have to open the chassis again.😀
Just saw your last post, looks like we are building the same setup with the same transformers lol!
I just ordered two 500VA Toroidy monsters, the ones with the stainless steel covers. Are those the ones you have too? If yes, can I just use the same spec components you got calculated for your setup? 😎
Basically all I need is Rs1 value.
I just ordered two 500VA Toroidy monsters, the ones with the stainless steel covers. Are those the ones you have too? If yes, can I just use the same spec components you got calculated for your setup? 😎
Basically all I need is Rs1 value.
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dovia83,
Those transformers look awesome, but they are not the ones I have. I have the next level down Audi Grade transformers without the steel covers. They each have twin 50 V secondaries.
So with 0.01 uF and 0.15 uF caps I measured 20.9 ohms for one secondary and 23.6 ohms for the second. So based on this I plan to use a 22 ohm resistor on each secondary.
See my Quasimodo set-up below. The picture on the left is before setting the resistance and shows the ringing. The picture on the right shows the circuit with the approximately 22 ohms dialed in.
Where did you get that cool little pcb?
Hope this helps,
John
Those transformers look awesome, but they are not the ones I have. I have the next level down Audi Grade transformers without the steel covers. They each have twin 50 V secondaries.
So with 0.01 uF and 0.15 uF caps I measured 20.9 ohms for one secondary and 23.6 ohms for the second. So based on this I plan to use a 22 ohm resistor on each secondary.
See my Quasimodo set-up below. The picture on the left is before setting the resistance and shows the ringing. The picture on the right shows the circuit with the approximately 22 ohms dialed in.
Where did you get that cool little pcb?
Hope this helps,
John
Attachments
Thanks for all the info!
These PCBs are part of the W12 dual mono PSU kit from R. Thatcher. https://tinyurl.com/bxabsvbw
I'm using this PSU for the Wolverine build.
In the process of ordering Cheapomodo so will have the numbers soon, and will post here for others if needed. My trans in 2 x 45, 500VA.
These PCBs are part of the W12 dual mono PSU kit from R. Thatcher. https://tinyurl.com/bxabsvbw
I'm using this PSU for the Wolverine build.
In the process of ordering Cheapomodo so will have the numbers soon, and will post here for others if needed. My trans in 2 x 45, 500VA.
Who is the top quality people that can design a Linear Regulated Power Supply?
Must be very low noise (uv to nv)
Ability to run 5A on the +-48vdc lines with minimal effect on the the other voltages
CT Transformer is 117vac input and multi-tap secondary
I need the PS outputs to be:
+-48vdc
+-12vdc
+-19vdc
+6.3vac
Must be very low noise (uv to nv)
Ability to run 5A on the +-48vdc lines with minimal effect on the the other voltages
CT Transformer is 117vac input and multi-tap secondary
I need the PS outputs to be:
+-48vdc
+-12vdc
+-19vdc
+6.3vac
Top Quality People:
Wayne Colburn, Pass Labs
Robert Dobkin, founder of Linear Technology
Carl Nelson, analog guru
John Curl, analog guru
Nelson Pass, analog guru
Bruce Hofer, founder of Audio Precision
Dmitri Danyuk, analog guru
Dennis Monticelli, TI Fellow Emeritus
Wayne Colburn, Pass Labs
Robert Dobkin, founder of Linear Technology
Carl Nelson, analog guru
John Curl, analog guru
Nelson Pass, analog guru
Bruce Hofer, founder of Audio Precision
Dmitri Danyuk, analog guru
Dennis Monticelli, TI Fellow Emeritus
