Morgan Jones BALANCED?

vvs_75 · 2nd April 2007, 05:53 PM

Just finish my Cavalli-Jones four days ago and already thinking how about go balanced?

Does anybody did balanced MJ or knows who did it?

Before I go for it I just want to know do I have to build duplicate or I can use PSU from my amp that I already have and just and tube stages?

If I have to build the hole amp again I will leave this idea alone!

Thank you for your time!

Eusebius · 2nd April 2007, 10:23 PM

Morgan is ex-BBC so like most broadcasters was familiar with balanced. But many of us use balanced push pull for various reasons. the obvious problem is that it's twice the tubes and twice the needs of the power supply, but then it does give you some more output. I used balanced when I found that DHTs were less microphonic in balanced operation.

Your power supply will have to do more - depends on what it's rated for. If it's just running the input tubes in balanced operation that won't add much.

Eventually you end up with interstage transformers and constant current sinks all the way through. One benefit is that the shunt attenuator is easy to build - I'm personally happy with a 12 way make before break rotary switch for a stepped attenuator. Balanced makes for quite easy construction once you can manufacture your own constant current sinks. Look in Morgan Jones 3rd edition page 134 (c)

Andy

vvs_75 · 2nd April 2007, 11:52 PM

Thank you Andy!

I am happy with my amp. I just thought that it's much easier to turn it to a balanced.

And I am definitely going to buy the book!

Thanks again for you help!

Vlad