Comments on: King-Vibe Amplifier

By: rrusston

rrusston — Fri, 01 Feb 2013 02:53:16 +0000

The 6X4 was generally much more reliable if you must have a 6.3V heater cathode rectifier tube, but as the poster says, the only sane reasons to use tube rectifiers are for the specific voltage drop curve in a Class AB guitar amp or if you are building out for a nuclear war or other major EMP event. In small signal devices or Class A amplifiers of any type it’s of no benefit. In a Class B amplifier it’s ironically of no use either since to get them to work at all you have to have enough reserves that there is very little drop, which is why all those old Altec and Stromberg transmitting tube amps have two or three rectifier tubes or gas tubes.

Zenith used a 3 volt heater rectifier tube in its bigger color sets in the early 60s, which I have never heard of any guitar amps using. It was the highest current rectifier tube (aside from Tungar bulbs) in the receiving tube armamentarium and is in later RCA manuals. I’m sure any winder would make you a transformer with the right winding today.

By: Bafflegab

Bafflegab — Sun, 20 Jan 2013 03:47:49 +0000

Mostly the 6X5 was used in car radios, although some home radios especially by Philco used them. They were interchangeable with the 0Z4 gas rectifier in many but not all car sets.

A Google search reveals that they are considered highly troublesome.

.philcoradio.com/phorum/showthread.php?tid=1080

I don’t understand why you insist on running tube rectifiers in Class A single ended amplifiers, because the particular voltage dropping characteristics of rectifier vacuum tubes (or gas tubes) have no effect on the sound. A resistor would do the exact same thing.

By: chris

chris — Fri, 18 Jan 2013 22:35:25 +0000

In reply to j-gandalf. I know that it appears in a lot of pro audio devices of the 40s and 50s, and I use them in most of my pro audio builds.

By: j-gandalf

j-gandalf — Fri, 18 Jan 2013 20:37:55 +0000

You do know the 6X5 has a long and thorough reputation, right?