Magnavox AMP142AB

[duffy878]

Hey guys,

Just getting started on my next project and with that, of course, comes some questions. I picked up this Magnavox amp on e-bay a few weeks ago and plan on turning it into some sort of Franken-Vox.

One of the first things I noticed was the PI, a paraphase. The B+ going to the Inverter and the AF Amp is around 120VDC by my calculations. I would like to increase this to more like 280-300VDC so I can have more gain at to the additional Pre-amp tube I'll be adding. Any down side to bumping up this voltage? From my understanding as long as I keep the voltage the same to the AF Amp and the Inverter, it will function properly.

My other question has to do with the OT. I'm not sure which wires are for which output impedances... there are three: Black, Orange, and Yellow (which is grounded).

I'm also considering using the JJ/Tesla multi-cap (40/20/20/20) which would be increasing the filter cap values a bit. I'm aware that the rectifier tubes data-sheet specifies what the first filter cap should be, but with two rectifier tubes in parallel would there be any harm in increasing the 30uF to a 40uF?

Thanks Guys

[sgunn]

yellow and black are your speaker wires 4 ohm load

[duffy878]

awesome, thanks.

So then orange is what? 8 ohm tap?

It seems weird to me that yellow is grounded and black is the positive audio.

hm, go figure.

[sgunn]

There's no 8 ohm tap check your spec sheet I think it's .38 ohm not sure what you'd use it for, maybe someone else has some insight on that,I use one with a 4 ohm speaker.