Going Linear with the Caiman

[trailer]

Yes, seconded, please keep on with the new mods. I've learnt so much over the last couple of years owning a Beresford or two. (I even remember having to ask what "op-amp rolling" was at one time). Mind you, my soldering skills have not improved I hasten to add.

[Gazjam]

Whats soldering?

[fmzip]

I bought the Caiman and the Tc-7520 because it was moddable!

I look forward to coming on here for some new ideas.

Please don't change you marketing strategy, keep the ideas coming!

[Ikemen]

I can handle the soldering, but of course desoldering is where things can get frustrating for a noob like me.

HELP while I'm here. I want to take off the front board to try the 12k resistor mod, but once the screws are off, the volume control holds the board in place. How do I take that off without damaging anything please?

[HighFidelityGuy]

I can handle the soldering, but of course desoldering is where things can get frustrating for a noob like me.

HELP while I'm here. I want to take off the front board to try the 12k resistor mod, but once the screws are off, the volume control holds the board in place. How do I take that off without damaging anything please?

Carefully pull the knob off the shaft of the volume control. Don't snigger.
Then once that's off there's a nut and washer to remove. Once they're off you should be able the lift the boards out. I doubt you'll just be able to get the front board out due to the length off the shaft. I find the best way is to lift both boards in the middle so the edges with the sockets and buttons come out last. Also be careful with the gold buttons as the have a habit of flying everywhere.

I hope that helps.

[Ikemen]

Thanks, I went ahead and forced it as you suggested. It was damn tight and only really came off by turning it all to way to the right and half screwing it off, pulling it off.

Thanks again.

[AndrewR]

Just been wondering. With the passive mod removing the op-amp board, this should lower the current requirements of the DAC. This might mean some form of CLC (capacitor - choke - capacitor) smoothing circuit could be feasible on each rail...

Any thoughts?

Andrew

[MartinT]

A third order choke like that would be very effective at filtering out noise. However, it would exhibit high output impedance and would not respond very well to the current demands of the DAC. Better to go with an active stage such as the Murata or Dexa regs.

[Clive]

I've been thinking about linear supplies for the Caiman. Shouldn't the 10,000uF capacitor be replaced by something like a 10uF film cap if the linear supply uses a voltage regulator? Most regs do not like charging up such a big cap and the big cap will downgrade the supply performance in that it's the big cap that determines noise & impedance, not the voltage reg. If using a non-regulated supply then the big cap is fine.

If a 10,000uF is wanted for use with a reg it should be placed following the bridge rectifier and before the reg (more than 25V rating will be required, so not the same cap).

[MartinT]

Good point, Clive. What's the biggest high quality cap we could get in there?