Upgraded MP-1 transformer

[rnolan]

Ok, so my take on the discussion is the MDRT can run of different mains but requires a switch set up so you can select the right taps on the transformer and they are solid old school kick ass transformers, not like the new switching transformers (and I side with MJMP here, the older rock solid are the go).
So MJMP, what would the switch and associated circuit look like to switch from 110 to 240 ?

[MarshallJMP]

Well the MDRT has 2 110V windings,so for 110V use put them in parallel,for 220V put them in series.

[MarshallJMP]

Was the MDRT installation designed with a specific MP-1 tube compliment in mind?

Reason I ask is that all we change is a filter capacitor and the resistor that establishes the cathode ground reference voltage.

Since we do not adjust the cathode or plate resistors it seems like it was designed to bias a certain tube (e.g. Bias)....Thoughts?

Is the purpose of that C131 capacitor to filter out signals above 10000uf? It appears to be a filter rather than a coupling capacitor. Why did we use 10000uf for the MDRT vs 4700uf for noise mod V2 without the MDRT and what I think is 11300uf from the original schematic?

Thank you


David

No it wasen't,Machiniator designed it to give the MP-1 the transformer it needed,with the correct voltages and more then enough current.

The 10.000µF filters the hum going to the heaters.The original tranny has sometimes startup problems with a 10.000µF but the original 3300µF can be replaced with a 4700µF if you have the orignal transformer.Did some testing and this as high you can go,the MDRT has no problem at all with the 10.000µF.

[trader144]

Ok thanks

[rnolan]

Well the MDRT has 2 110V windings,so for 110V use put them in parallel,for 220V put them in series.

Ok so fairly simple switch ? (bit like PU series parallel switch but beefier  >:D )

[feline guitars]

Just fitted the MDRT to my 230v  unit and it is well worth it
I know it's relatively expensive but it really brings the MP1 to life.