Dual km 54 PSU transformer

[SparkleBear]

Hey all, I'm planning to build a dual km54 power supply for a "poor mans KM54" build. Do I need  separate mains transformers for each mic or can I use one transformer to feed each of the two psu boards?

Thanks for the input!

Eric

 

[TLRT]

I did the same for Gefell M582's, the best if you have dual setup, so the mics can be operated separately.(so dual mains toroids, 2 PSU panel, switches,jewel lights etc)

 

[SparkleBear]

I did the same for Gefell M582's, the best if you have dual setup, so the mics can be operated separately.(so dual mains toroids, 2 PSU panel, switches,jewel lights etc)

That sounds awesome! What tubes did you use in those mics? Was it a mod job or just you needed psu for the original pair?

Also, what chassis did you choose for that beast?

Cheers
E

 

[TLRT]

The mics are stock with ec92 tubes,I used a Sony DXC camera's control box with some customization

 

[lampas]

Didn't try it but:
https://www.eleccircuit.com/dual-dc-power-using-2-terminal-transformer/

There are many ways to build the Dual DC power supply rectifier from a transformer that has one secondary coil.This good way as Figure 1 use two bridge diodes. The first section is normally working, others section (D1-D4) will work by AC signal from C1 and C2. To filter DC voltage of out others bridge diode of transformer. It cause we can connect directly the positive of to the 0 volts. Thus, the output will be symmetric both positive and negative.

Dual DC power using 2 terminal transformer

And since C3 is charged by impedance higher than C4. Because value of C1 and C2. Thus value of C3 so must be more than C4, to cause ripple of DC voltage symmetrical both positive and negative.

The voltage of capacitors must be same maximum AC voltage of transformer. In circuit, use 15V at external current is 0.1A cause ripple voltage of 1V.

If need to has low ripple voltage than this we must to use capacitance more and do not voltage and current rate of diode to higher than the power of transformer and load.

 

[rmburrow]

how does that mic have room for a 6AB4 (EC92)?  I thought the KM54 used a AC701 with a 4 volt heater.  Heard of triode connected 5840, 5703, 7586, EF800, EF86, etc. used in mics... personally used 5703, 7586, 5840 in mics with 6 v heater...haven't used the 6AB4 but have a couple on the shelf...

For dual mic, clone the Neumann NSM supply.  This was used with the early SM2 mics, I like the way the HT is regulated right off the rectifier with the 150B2  (OA2 with socket rewiring) VR tube.  I used ni cad batteries in place of the old "stabilites" ... the capacitance generated by the electrochemical action is extremely high...and may even cover you during a session if there is a power glitch...fwiw

 

[TLRT]

how does that mic have room for a 6AB4 (EC92)?  I thought the KM54 used a AC701 with a 4 volt heater.  Heard of triode connected 5840, 5703, 7586, EF800, EF86, etc. used in mics... personally used 5703, 7586, 5840 in mics with 6 v heater...haven't used the 6AB4 but have a couple on the shelf...

For dual mic, clone the Neumann NSM supply.  This was used with the early SM2 mics, I like the way the HT is regulated right off the rectifier with the 150B2  (OA2 with socket rewiring) VR tube.  I used ni cad batteries in place of the old "stabilites" ... the capacitance generated by the electrochemical action is extremely high...and may even cover you during a session if there is a power glitch...fwiw

how does that mic have room for a 6AB4 (EC92)?
Check picture