sckott, Steve, toob doods - what's a 6B4G???

I was bad and steered the naughty bits/suspension thread over in the music department; toob dood sckott mentioned a tube I wasn't familiar with, the 6B4G - what in the name of Mullard is a 6B4G???

 

A fairly inexpensive push-pull directly heated triode.

http://www.arrakis.es/~igapop/6b4g_push_pull_amp.htm

The one I'm building on parts for:

http://www.pmillett.addr.com/6B4G push-pull amp.htm

If you look at the shape and size of a 6B4G, it looks like the tube on my Avitar, which I THINK should be a 2A3.

The tube is actually a great performer, but demands quite a bit in the capacitor dept. I've seen a lot of 6SN7's used for inputs (or types) and not only these....

It'll be fun.

 

Ahhh, not a well known tube about town - been reading audioXpress on the side, sckott???

 

Right. I have all ceramic octals for the base. All tubes in that Pete Millett receipe are one type, and use fairly easy-to-git transformers. It IS obscure, as many popular tube sites don't carry it. Angela does though, as is the trannys.

Pete wrote a few articles for AudioXpress. I would recommend that mag for DIY'ers. Lots of neat stuff in those rags. I haven't been very excited about a mag since this one. Very thoughtful.

I'm building it to follow a schem for the 1st time unattended, and I only know the amp is a solid performer. I don't know if it will kill alything else I have, but that's also in the fun.

 

nice looking layout and execution on the links!

I'd like to hear it.

 

If the LCR caps are stil available in the spring, I'll let everyone know.


If it sounds good, I'll be happy. Tis mostly a mountain I want to climb and say, "I did that all by myself! Goo goo...."

 

A 6B4G triode is the exact same tube as a 2A3 triode (used in my Bottlehead Paramours and some other SET amps) except it needs a 6.3 volts (with 1 amp of current) on the filament instead of a 2.5 volts and 2.5 amps like a 2A3.

Since the 6B4G has a higher filament voltage than a 2A3 its very difficult to control hum in single ended applications, so its used in push-pull where the hum usually cancels.

 

Glass-lovers, thanx for the info!

 

Sckott:

Have you ever thought about an interstage coupled push-pull like this?

http://www.meta-gizmo.com/Tri/interstage.html

I've been slowly getting together the parts to build a 2A3 push-pull. Since I already have 2A3's for the Paramours it makes more sense than going to a 6B4G.

Here's an interstage coupled 300B push pull for anyone who's interested:

http://www.meta-gizmo.com/Tri/RRM/sun.html

Steve:

Are the VAC amps that you used in the past interstage coupled or do they use some kind of Mullard phase splitter like the old McInstosh/Dynaco/Eico equipment. I don't think the VAC web page goes into that kind of detail.