Aleph 30 transformer recommendation

[arold19]

Dennis Hui, what is the manufacturer of your transformer ???? Plitron ???
Because I have to change my transformer on my Aleph30..

Thank you

[Dennis Hui]

Originally posted by arold19
Dennis Hui, what is the manufacturer of your transformer ???? Plitron ???
Because I have to change my transformer on my Aleph30..

Thank you

Yes, it is a Plitron transformer, though I obtained
it from a retail store.

Dennis

[SteveA]

Originally posted by BrianDonegan
I am using a couple of Antek's 16V trafos. You could also, since you are in the US, use one of the 34V trafos, and wire the primaries for 220, which will net you dual 17V secondaries, or a 39V for 19.5V.

Brian,
I bought an Antek 39-0-39V transformer (700VA). I used a variac to help check secondaries and the power supply, however, at roughly 40-50% of full mains voltage the variac starts to buzz (before connecting to PSU). I am a bit apprehensive about going any further. What would cause the variac to make noise?
SteveA

[BrianDonegan]

Not sure. My guess would be phase variance. Did you try just powering up the trafo with nothing connected to it's secondaries?

[SteveA]

Originally posted by BrianDonegan
Not sure. My guess would be phase variance. Did you try just powering up the trafo with nothing connected to it's secondaries?

That's what I did. I was just monitoring the voltage at the secondaries (so I could "pair up" the correct secondaries).

I just finished an Aleph 4 (actually a pair of A4 mono's) and the variac made a similar "noise" as I powered up. I was able to go to full mains voltage, but this time the variac seems to have increased it noise level.

Steve

[BrianDonegan]

I menat just powering uop the unconnected trafo without the variac in the equation.

[SteveA]

Originally posted by BrianDonegan
I menat just powering uop the unconnected trafo without the variac in the equation.

Nope, haven't done that yet. I'll check it out tonight.
Steve

[hifimaker]

For an Aleph30 you need 25vdc PSU. You would need 21 to 22VAC secondaries. I'm using a torid with 45VAC secondaries using the 230VAC primaries for 120VAC to get 22.5vac for secondary. I''m getting 24.99VDC PSU out using a CRC circuit.

Here's a picture of my Aleph30 trafo and PSU.
My 1st Aleph Amp

Good luck,

-David

[SteveA]

Originally posted by dw8083
For an Aleph30 you need 25vdc PSU. You would need 21 to 22VAC secondaries. I'm using a torid with 45VAC secondaries using the 230VAC primaries for 120VAC to get 22.5vac for secondary. I''m getting 24.99VDC PSU out using a CRC circuit.

Here's a picture of my Aleph30 trafo and PSU.
My 1st Aleph Amp

Good luck,

-David

Hi David,
I saw your thread, I think I may have the same heatsinks. I figure I'll get ~23-24V rails with this (Antek) transformer. I saw some Antek's on Ebay (400VA 22-0-22 if I remember correctly). A pair of those might do well but first I'll see how this one works.

Steve

[hifimaker]

Hi Steve,

Attached is a pic of the PSU simulation I used, and it turned out to be very accurate. I used a small amount of resistance to achieve the Aleph30 spec of 25VDC with 22.5VAC trafo secondaries. I actually had 24.99VDC using the mini-aleph PSU boards and parts from the GB with 4 3 watt resisters per side.

-David