12v tx for 1875

[sandyhooker]

Either way is acceptable. I found my little amp to be just right for computer operation.

[AndrewT]

Originally posted by wicked1
I have no issues w/ a good old iron xfrmr, and started looking into that.

Is there a difference in the power supply if I go w/ a 12,0,12, vs something that has 12,0 + 12,0?
Would I just share that common ground?

Hi,
there are at least two big differences between Toroid and EI.
The Toroid has lower regulation.
The Toroid has less attenuation of the HF.

Operationally there is a big difference between 12-0-12 and 12-0 + 12-0.
The 12-0 + 12-0 can be easily converted to Centre tap and both versions suit a single single rectifier with the centre tap connected to Audio Ground.

The 12-0-12 cannot be converted to dual secondary.
Only the dual secondary can use the dual bridge rectifiers, with the zero volts line connected to the Audio Ground.
In a monoblock this makes absolutely no difference.
In a multi-channel amplifier, this can make a big difference in the flexibility of organising your separated audio grounds.

If you plan to build any multi-channel amplifiers and want the flexibility to experiment with the grounding, then buy the dual or quadruple secondary transformer.

[sandyhooker]

Originally posted by AndrewT
Hi,
there are at least two big differences between Toroid and EI.
The Toroid has lower regulation.
The Toroid has less attenuation of the HF.


The 12-0-12 cannot be converted to dual secondary.
Only the dual secondary can use the dual bridge rectifiers, with the zero volts line connected to the Audio Ground.

In this particular case dual secondaries are'nt necessary. It is doubtful that dual 12 volt secondaries would be used to power multiple amps.Get a Marlon Jones iron job for little money and enjoy the sound.

[wicked1]

I just got my PCB's and it looks like in this case, it doesn't matter (as the previous poster said)
There is no provisioning on the board for 2x full bridge rectifiers.
Same goes for the mini-a PS pcb, but I'll ask my questions about that one in the correct forum. (I haven't seen a single aleph PS schematic that doesn't use dual rectifiers)

[wicked1]

Well, I got them built last night.
I found an old audiosource SS3 surround sound processor w/ a 14-0-14, 100va tx inside. ALSO, a nice double heatsink. The SS3 was a little chip amp, w/ the other brand (not lm) chip of about the same power as the 1875. (sorry, parts aren't near me and I forget what chips it had)
So, finding that ss3 in a stack of old stuff in my basement was a huge help on this, and saved me a lot of money!

It sounds great on my 'big' speakers (little 6" full rangers) and I'm sure it will be perfect for its intended use as a computer/desktop speaker amp.