After lot´s of fight with hum... HERE is my new DIY MB1

[tony dB]

errr, I should have read better.

Cool that Edcors turn out well!
I've used them in a few boxes with good results too btw. :thumb:

Tony.

 

[NewYorkDave]

P-tec phono pre schematic

 

[rafafredd]

WOW! Thanks Dave!

 

[rafafredd]

My four channels tube pre schem:

 

[Gus]

rafafredd

The top pre circuit does not look right

The cathode section at the output stage has a DC feedback to the cathode of the input.

Why all the resistors in the output cathode leg?

R2 looks like it would add noise

That is some bias setup!


The bottom stage looks more standard.

 

[rafafredd]

The top pre circuit does not look right
The cathode section at the output stage has a DC feedback to the cathode of the input.

This is Pultec MB1 allright!

Why all the resistors in the output cathode leg?

To get as close as possible to the orignal 17.5k value...

R2 looks like it would add noise

It´s quiet enought for me as it is. I do think it would be possible to ground the negative side of the secondary of the input transformer, but as I said before, this is Pultec MB1 allright, and I do like it as it is...

That is some bias setup!

Do you mean for the heaters? :green:

The bottom stage looks more standard

Yeah, but the upper one sounds better to me...???

 

[Jonkan]

Hey Rafaredd! I see that your using OEP in your 1272 clone.

How do u like them in that circuit? Im thinking of using OEP for my clone also...

Any thoughts?

/Jonas

 

[OneRoomStudio]

I'm thinking about putting a pair of these together, does anyone see any problem with using Cinemag CM-75101APC as the input? It seems like the Edcor will serve me well on the output (especially financially) and I have two CM-75101APC laying around so....It sure would make things easier and cheaper.