Good day everyone.
Currently I am using a TCC TC-750 phono stage with premium AC adaptor (its only an SMPS from
this ebay link). If I get
this upgraded TeraDak 12V DC power supply, how much improvement can I expect from it?
My turntable is a Telefunken S500 + Syrinx PU2 arm + Audio Technica AT51e cart. Downstream I have Lehmann Black Cube Linear pre + Edifier Studio 7 monitors.
None, it would even be detrimental, as the highest voltage output of the TeraLink is 10 V. TC-750*s main weakness is relatively very low ( but sufficient in practice ) overload point, which is directly proportional to the power supply voltage. Obviously, power supply should not exceed +15V DC - or slightly above.
Officially, TC-750 runs off 15 V DC - but real measured value is approx 12 V DC. In other words, ideal value for the quietest and lowest output impedance ( ie - the best ) power supply one can possibly get - battery. Sealed lead acid battery 12V 4.5 Ah with the lowest output resistance/highest output current is to be preferred - along with some smart car battery charger. Both the capacity and output impedance may well be regarded as vast overkill for the application - yet it is the best you can do for the TCC-750. For the cable between the battery and preamp please use the heaviest gauge coaxial cable that will mate with the biggest DC power jack you can find - prefabricated cables are usually not shielded and gauge tends to be low; use shield for the ground and core for the +12 V DC. An alternative might be a prefabricated cable with copper shield/snake protector connected to the ground. Always observe the correct polarity.
Just to stay on the safe side, please use battery with different width of its + and - output terminals - repeated accordingly on the cable side. Colour coding is good - different width makes it almost 100% secure against unfortunate mistake in connections after recharging the battery.
One can go crazy and design a circuit with two batteries, one connected to the load, one charging - making it round the clock capable power supply - and placing it in a high end enclosure with 1 inch thick front plate. For those with $$$$ to burn .... A 4.5Ah battery, tucked neatly out of the way/sight, will power the TCC-750 for longer than anyone can listen to music in domestic environment, with the time in between the listening more than sufficient to recharge the battery.
In audiophile terms, it means quieter, blacker background, better dynamic range, better channel separation and better bass in particular. TCC-750 is quite sensitive to wiring; make sure the wiring from your TT ( both RCAs and ground ) is up to the challenge ( if there is any hum with its own power supply, or even RFI pickup, first make sure to eliminate this ) - improvement in power supply can not help with those problems.
For anyone thinking the above is crazy for a $50 or so phono stage - it is not. If yet another 50$ or so is spent for better components within the TCC-750, particularly capacitors ( and, if you really are finicky regarding the accuracy of the RIAA curve , some precision resistors/capacitors ), the result is a very capable MM only phono preamp. Which, for all practical purposes ( save for above average output MM cartridges playing very hot recorded records - and, obviously, MCs) should be all that anyone might ever need. Only front ends ( TT, arm, cart ) in highish four digit $ and above might warrant the use of something better.
Remember, in entry level ( anything up to say 2K for TT/arm/cart/phono pre ) the money spent on better stylus (say from Ortofon 2M Red to 2M Blue, etc ) will yield much better sound than staying with the lower quality stylus and putting that difference towards better phono preamp.
