Pre3 problem.

[pre65]

Originally Posted by Ali Tait

The Aikido not better then!

Not as I built.

BUT, I would think one built on the proper PCB might be ?

[Ali Tait]

Dunno, find out when mine gets here, it's still en route.

[david]

Depends on your ears (and ancillary components)! My Aikido with Charcrofts, Mundorf ZNs, and Mills resistors is very comfortably ahead of my modded Pre 3 (with TJS and similar mods). Before that the CF Pre I made with the right and left power supply decoupled also outperformed Pre 3. But Pre 3 is good, and has it's charm. My main issue that led me down the road was its too high gain and also that running its tubes full tilt you get quite a high hiss on the output, compared to silence with the modded CF and inky blackness with the Aikido.
David

[Richard]

Originally Posted by pre65

I'm more inclined to blame the socket.

I re-soldered the valve bases a while ago when the problem first occurred.

Perhaps I will re-try the 5814wa at a later date.

Yes I've got 2 or 3 types of 5814 and various ECC82s but have never tried them in there, I got as far as the second ECC82 type and it was so good I just left them in! A tip on soldering pcb type valve bases if you don't already do it is to fit a valve to the socket first which then ensures the contacts are nicely aligned as otherwise they can float around a bit and may end up not contacting the pins so well.

[pre65]

I never really got to the bottom of this problem, and as a result Pre3 has sat, unloved, for many a year.

So, now I am going to get it sorted. I've asked Matthew to sell me a new PCB and two new valve bases.

I'll let you know how I get on.

[pre65]

Thanks to Matthew I now have the PCB and 2 valve bases.

I'm in the middle of refurbishing the 833a amps at the moment (one done so far) so I will wait till that job is completed before starting.

[pre65]

I got bored today, so I took the PCB out of it's packing and inserted PCB pins in the relevant holes.

I've ordered the resistors (Takman) and 470uf caps (Elna Silmic 2) from HFC, and will use the Mundorf Mcap Evo that Bob gave me for the coupling caps.

[pre65]

Got a question on Pre3 PCB wiring.

I found my parts list but not the assembly instructions.

On my original build PCB positions OPR- and OPL- have PCB pins fitted, but no wires connected to them. Is that correct ?

[Greg.]

Do you want me to send you the instructions?

[pre65]

Originally Posted by Greg.

Do you want me to send you the instructions?

That would be nice Greg, postal of PDF via Email ?