Center tap torroid wiring to peter daniels kit???

[Socrates428]

Hi,

I have two of the Avel 2x25 120 transformers from apex jr and the peter daniels premium/gold kit, setting up a dual mono amp, and having a heck of a time figuring out how to wire the tranies up and the manual is dated/uses different boards/useless.

Do the orange/red go to the two AC1 inputs on both rect. boards and the black/center tap go to the PG-? Are only the 4 outside diodes used and the center 2 liked per the manual at http://www.audiosector.com/nigc_kit-users_guide.pdf on page 15? Do I still make all the normal PS out to chip board connections just as per the manual, (PG- to PG-, PG+ to PG+, V- to V- and V+ to V+), now that the center tap is using one of the PG- holes?

Can I link the center tap as suggested on the apexjr site and use all 8 diodes (that seems wrong???)?

As an aside, what does having a center tap vs duals do sound quality wise, ie, would a dual with all of the diodes be more powerful or sound better? Thanks much for any help, especially with the wiring, especially if pics are included !



PS:
Here's the full spec from apex jr on the transformers I have:

Avel-Lindberg Inc

Input: 2 X 120Vac 50-60Hz 3 1/4" Dia X 1 1/2" Tall
Output: 2 X 25V @ 2 Amps 100Va
$17.95ea

[AndrewT]

would a dual with all of the diodes be more powerful or sound better?

no.
The dual rectifier drops 2.8v instead of 1.4v over the full rail to rail voltage. This makes the amplifier slightly less powerfull. But I think you will never hear the small, but measureable, difference it makes to output power.
The proponents of the Dual Rectifier claim it makes for less hum and a quieter supply. I have not been able to measure any difference (with my limited equipment) between the two types.

[Peter Daniel]

I should have done it long ago, but here it is: a proper way to convert dual bridges board into single bridge/CT transformer application.

You only install 4 diodes and add two jumpers. One secondary wire from transformer connects to a hole marked AC1, the other secondary wire connects to a hole marked AC2. You either use right hand holes, or left hand holes, you can't use two on the outside or two on the inside as this will create short circuit.

The centertap wire DOES NOT connect to the rectifier board, it goes directly to the amp PCB. Here, you can connected to either of the holes marked as PG+, PG-, CHG. The most appropriate way would be connecting it to one marked as OG, and taking the speaker Output Ground from a same point. You can do it by attaching second wire underneath the PCB.

In that way, you do not install any caps on rectifer board, as there is no ground reference there. Those caps are not really needed, if you still want them there, run additional ground wires from amp board to rectifier board by connecting PG+/PG+ and PG-/PG-.

[Peter Daniel]

Originally posted by Socrates428
Do the orange/red go to the two AC1 inputs on both rect. boards and the black/center tap go to the PG-?

As an aside, what does having a center tap vs duals do sound quality wise, ie, would a dual with all of the diodes be more powerful or sound better? Thanks much for any help, especially with the wiring, especially if pics are included !

In your particular case, orange connects in place of blue wire (in my pic), read connects in place of grey wire, black/centertap goes directly to the amp board. From a modified rectifier board you need to run two wires connecting V+ and V- with the amp board.

Dual/single bridges will not affect power output in any perceivable way. They may affect the sound quality though, in what way it will depend on your particular system and listening experience.

I noticed slight changes in the soundstage and overall air, but last time I was doing comparison was 3-4 years ago so I may not remeber well

[Peter Daniel]

BTW, I've recently built Plitron toroid, dual bridges power supply for GainCard and it worked really well.

[Panelhead]

Peter,
How did it compare to the power humpty? The Plitron powered supply, I mean.
I like using the scheme you mentioned here, diodes from rail to rail, center tap to board. I think it should reduce diode switching noise.
Good work


George

[Peter Daniel]

Originally posted by Panelhead
How did it compare to the power humpty? The Plitron powered supply, I mean.

I didn't compare it with Humpty yet, as I had ony GainCard for my use. I might do it later though, as I'm also curious how they compare.

I did compare AMP-1 with GainCard though, running from a same PS. There is certainly a difference in a sound, and both signatures will appeal to different tastes.

[Socrates428]

Thanks so, so much for the reply, Peter. I got it up and running on my test bench, running the center tap to the speaker ground, using all the caps in the kit with the PG-/+'s connected on the boards, per your suggestion. Nothing buzzed, sparked, hummed, exploded or even caught fire, just the sweet music of Zero 7 running into my junk test speaker.

Wish I would have thought to ask here 2 days ago, as my PS board would look MUCH nicer (I already soldered all 8 diodes together and installed the trannies per the apexjr site), and won't be using the nice clear acrylic case anymore, as, again, the boards look like a battlefield with all the soldering/de-soldering. Thanks again. Can't wait to get them in a finished case and hooked to the the big rig and see how they compare to the Spectron, Ice and Hypex amps I have here!

[Peter Daniel]

I have some spares of those PS boards, if you want I can send them to you free of charge, so you can still use the acrylic case

[Peter Daniel]

Originally posted by Panelhead
Peter,
How did it compare to the power humpty? The Plitron powered supply, I mean.
I like using the scheme you mentioned here, diodes from rail to rail, center tap to board. I think it should reduce diode switching noise.

Although I didn't compare Humpty, I recently had a chance to experiment with Dumpty and both 47Labs transports.

Somebody asked me to to build custom supply for a Shigarki. I used 70VAVA Hammond and 2 MSR860 diodes. That supply compared very favourably with the Dumpty, in fact, it wasn't inferior in any way and I preferred it personally.