Only with an impedance of absolutly zero ohms, at all frequencies, at the load terminals would you not be able to hear the effects of additional components or cables on the power rails. Whilst it is currently not possible to acheive zero ohms, over a wide bandwidth, the closer you approach this ideal the better the sonic results. People have different preferances in their systems as you and your friend find with the Optima and the Shunt regs. It is usual that the differences are relatively small at this level of performance and more a question of differing taste.
This last year I have had a lot of enquiries for a power supply for use with the Altmann BYOB amplifier, so I have prepared power supplies for this function. Due to the issues of cost and thermal management I chose my best series regulator topology for the job . The Red Top makes a good supply which is why Charles recomends it and any alternative supply has to at least compare favourably with the Red Top or it would be a wasted exersise. Not everyone wants to or is allowed to have a battery in the lounge so a good mains driven power supply is a useful alternative. I am just preparing the new PR3G Series regulator module for DIY enthusiasts. This can be used for amplifiers using single positive voltage power rails. Examples include Charlise, Altman BYOB amplifier, Trends, etc. The output impedance is comparable to the Red Top battery but over a wider bandwidth. The available current from then PR3G is 3 amps continuous and up to 10 amps transient and it can be used with a reasonably small heatsink rated at around 2 degrees C per watt. I can customise the module for much higher current capacity by replacing the output mosfet with a heavy duty isotop package that is bolted directly to a suitable heatsink.
The PR3G is a pure linear regulator and is very quiet with error amplifier devices specified for noise at 0.5 nanovolt root hz with a noise corner of 1 Hz. You can use it for vitually any function by customising the various parts. I have used this regulator topology to supply 10 amps continuously for a bank of four 6AS7 heaters in a Circlotron power amp, a moving coil cartridge head amp where noise is crytical, a power supply for the origin live DC motor used to upgrade record decks, Valve HT regulators at up to 450 volts. The list of different applications is large. I will also be preparing a negative voltage regulator board (NR3G) in the new year using the same topology but mirrored for negative supplies. I have used this negative regulator topology for operational amplifier or power amplifier supply rails paired with the PR3 to give a dual rail supply and it was also used to give the negative grid bias to the bank of 6AS7 valves in the Circlotron amplifier.
Toni, if you would like to try the PR3G regulator module against the Red Top battery I will send you one free of charge. It will be very interesting for other enthusiasts to have such a test completed by an independant enthusiast as it will cost £70 when set up for Charlise. With the addition of a transformer and a heatsink for the module it will cost substantially less than a Red Top battery and charger.
E-mail me at [email protected]
if you want a module to try a PR3G.