Minicap6 based integrated amp PSU - Page 3

mikesnowdon · #31 24-08-09, 11:06 AM

Quote:

I have a friend who works with ally extrusion and hes got some U channel offcuts for me. Im planning to mount a section of U channel in between the poweramps with the 2 Skpre boards mounted vertically on their side in the middle of the u channel. The Teddys's will mount by the TO-220 tabs on the outside of the u channel with the actual Teddyreg PCB's sitting just under the NAPA boards. The volume pot shaft extension can then run through the middle of the preamp assembly.

Here is the preamp/regulator assembly. Not finished but I thought I would put a pic up to illustrate what I described above. Just need to install TeddyReg components. There will be another pair of +/- Teddy's on the other side. The whole thing sits between the NAPA boards.

mikesnowdon · #32 24-08-09, 11:36 AM

Moved this post here.

sq225917 · #33 24-08-09, 12:47 PM

blimey guvnor, that looks corking

mikesnowdon · #34 24-08-09, 01:53 PM

Cheers fella

simonbrown · #35 24-08-09, 01:56 PM

No electrical insulation between TR components and heatsink ?!

mikesnowdon · #36 24-08-09, 02:00 PM

Coming soon!

Quote:

Not finished but I thought I would put a pic up to illustrate what I described above

mikesnowdon · #37 16-09-09, 04:14 PM

'ello peeps!

Got the preamp assembly all built up and did the extra wiring on the minicap6's.

All ready for testing tomorrow.

I used the SMD pads under the pcb for the preamp supply & ground wiring, unfortunately there wasn't quite enough ground pads so I had to scrape a little mask off the center track. That middle point is the main ground connection to the SKpre's. The outer +/- & grounds are to the teddyregs. (ignore red/black wire coming off cap, this is the 'sense' connection to the SSM).

mikesnowdon · #38 21-10-09, 02:50 PM

Fianlly got the Teddyegs done and wired up the power. Quite a bit of sag under load, almost a full volt on one of the regs. I set the voltage's to +&- 15v with no load, but with the SKpre modules connected I'm getting between 14.7 and 14.1v. Is this normal? Should I just reset the v'out under load or should I be checking for something out of place?

P0rn! to follow.....

mikesnowdon · #39 21-10-09, 03:09 PM

mikesnowdon · #40 21-10-09, 07:40 PM

(bump)

Is this voltage sag under load anything to worry about?

DubbLinn · #41 22-10-09, 03:17 AM

Good to see you got the Teddyreg sorted. I don't know what sort of volt drop you may expect but I am sure it is related to the load on the regulator. You might need to check as to what load the SKpre modules can draw. I am sure one of the resident gurus will be along to explain this issue.

Frank
ps. there are different options when building Teddyregs as regards the load carrying capacity, ask Teddy.

mikesnowdon · #42 22-10-09, 06:06 AM

Hi Frank.

According to the SKA audio website the SKpre 'supply current' is 7.5mA in its standard config (using the SKpre on-board regs). Im not sure what to make of this though?

The TR's don't seem to be getting hot so I'll power up and re-set the output under load then leave it on for a while to monitor things. Hopefully It'll be ok.

James Evans · #43 22-10-09, 06:10 AM

Looking really good Mike! Have you listened to it yet?

James

S-Man · #44 22-10-09, 06:26 AM

Quote:

Originally Posted by PigletsDad

The SK regulator is a weird circuit; the tolerance on the output voltage must be enormous, although it should be pretty quiet.

The SK reg is designed to give an output voltage that is a proportion of the (smoothed) input voltage. It works like an enhanced Vbe circuit i.e. reasonably low o/p impedance and ripple with decent load regulation but no line regulation at very low frequencies. It also has the benefit of being very fast and probably has a consistent o/p impedance with frequency.

Mike - have you listened to the SKPre (with on board reg) yet?

mikesnowdon · #45 22-10-09, 06:42 AM

No. Initially I was going to use it as-is with the on-board regulators. My problem was that I'm building an integrated amp and wanted to take a feed off the poweramp supply to power the SKpre's. The original plan was to take the 45v through a resistor and 24v Zener into the SKpre regs. I wasn't keen on the Zener and thought about using a LM317 pre-reg to drop the 45v to a lower voltage that the Skpre regs could survive. I just couldn't find the space for it though. So with a set of Teddyreg PCB's on hand I decided to use them instead of the Skpre regs. Im sure the SKpre regs are great but I've heard great things about the Teddyreg too. This is a bit of a suck it and see situation and if its dosent work out I'll try the SKA audio regs.