s.e.x. 2.1 shunt reg monoblocks?

[Jim R.]

So, I was just reading the product description of the s.e.x. amp on the bh web site and somewhere in there it mentions that  a shunt-regulated 2 watt monoblock can be built from the s.e.x. kit.  Has anybody done this?  Is this still feasable with the 2.1 kit?

Any help appreciated.

Thanks,

Jim

[Paul Joppa]

That statement was based simply on the availability of two tubes, one of which could serve as shunt regulators for the other. I think these ideas (including the push-pull idea) were in the context of it being an "eXperimenter's" amp.

I have run some speculative numbers, and keep coming up with a transformer load impedance around 5K-6K ohms. There are a few 5K parafeed transformers, though we don't have one in our inventory. I think the 6EM7 is better suited for this application, as it has a smaller plate resistance.

I'd be glad to share my first-cut voltages and currents - but that is only a few percent of an actual design.

[Jim R.]

Jim,
I've hooked up the computer and have struck a problem. The noise from the fan (that's
what I'm assuming it is) is very loud and doesn't go away. I assume it wasn't that
way when you shipped it, since I can't imagine that anyone would use something this
noisy as a music player. At this point all I've done is hook up the connections and
link my Bluetooth keyboard. Do you have any suggestions what I can do about the noise
problem?
Paul,

Thanks but the reasons for trying this were mainly because of the 6dn7's sonics and the new OPTs -- one thought being to buy two kits, build two monos and use the leftover iron set to upgrade my 2.0 amp.  Sounds like that's not likely to work out.

Thanks,

Jim

[Paul Joppa]

I agree that the sonics of the 6DN7 are superior. Because of the 6DN7's higher plate resistance (30% higher than a Type 45), it would have a poorer damping factor and make less power when operated at a lower voltage and higher current as needed for a shunt regulated stage. If those are not significant problems then it is useable - I'm just expanding on why I think the 6EM7 is better suited.

[Jim R.]

Paul,

Well yes, those are pretty significant :-)

I know I wanted another kit for myself, but I'm also thinking about the second (or is it third) one for my sister-in-law, whose ancient and patched together stereo is in need of replacement. That still gives me an excuse to buy two more kits.

-- Jim