I have just begun work on a radio that is labelled Breville 330J-2135 while I wait for some parts for another project. The valve numbers are stamped on the chassis and are EL3G, 6G8G, what looks like G07G but I suspect is 6Q7G. and 5Y3G.

In the place of the EL3G was a 6F6G (looks like an F). I know little about the EL3G and can find no info on it but the EL3 and 6F6G would seem to be quite different. Given I cannot find any info, nor an actual EL3G to fit, is the 6F6G a suitable substitute? if not, what is and what other mods would be required. There appears to have been no modifications other than exchange of valve types. To my knowledge and from a quick look at the circuit, the EL3G would have been the mixer, but the 6F6G is an audio amp. Maybe a backyard expert thought he was doing the right thing, or maybe it was just a mistake.

The electronics look immaculate. I have not replaced the caps (yes I know I should not have turned it on) but the interior looked in great nick so I brought it up on variac and current limiter. I was originally not going to restore it anyway but changed my mind. It came to life but the audio is very weak. I intend to recap it now, but would like to know where I can get an EL3G or good equivalent while I am fitting caps.

Kind regards
Kimberly VK2KMI

As you would probably know, a 6F6G is an early version of the 6V6G.
Breville of that era would probably use a 6V6G. So at some stage someone replaced with 6F6G.
Do not know where the EL3G fits into this, maybe EL33?
JJ (VK7ZJJ)

The EL33 is a higher output valve and in some cases needs to be wired differently to a 6F6G. If you put a 6F6G in place of a EL33 then all you will achieve is lower volume , but if you replace a 6F6G with a EL33 then you may have nasty issues . You did say that EL33(G) was marked on the chassis?

Yes EL3G is definitely marked on the chassis and would be mixer not audio amp would it not? The 6F6G is an audio amp isn't it?

The audio amplifier in this chassis is supposed to be a 6G8G by the way. I wonder did someone just put the wrong valve in the socket by mistake? Other Brevilles had an EK2G or 6J8G. I wonder if I could use those with/without some mods instead of the EL3G which seems to be unobtanium?

I think you will find the EL33 is the later version of the EL3.

I also have a feeling the EL3 has a different base.

The EL33 is octal like the 6V6

Clive. Yes the EL3 as a different base to the EL3G judging by what I can find. EL3G I can find nothing about

EL3G doesn't show up on any of the valve info sites. However the EL33 is a audio output valve. They may have missed the extra 3 or Used the G instead of the 3.
I think they just missed the extra 3 as G stands for Glass.

Ok thanks. I didn't now the G stood for glass. Learn something new every day. The position in the circuit is not one of audio output, that is the 6G8G. This is Osc/Mixer, then 6Q7G IF Amp? 6G8G RF Amp and AGC?, 6G8G Audio amp. EL33 would seem unsuitable.

Tempted to go with the EK2G/6J8G in the other Breville models

I think at this stage you should send us some photos.

Photos are here

https://wp.me/p14Tnu-wl

I'll take another look at the circuit in the morning. I am incorrect about the position in the circuit. I am away from the radio at present but going over the view in my mind. The mixer tube is def at the other end of the radio...big day at work not the best time to be troubleshooting. Sorry of course it is at the other, next to the tuning cap with the wire to the top. Something isn't gelling. I'll take a look over the next few days. The position of the EL3G is an audio amp, so I best take a good look in the morning. Sorry for the confusion.

EL3G seems to be an odd one. EL3NG and EL33 are both audio outputs and equivalents. I have found one Breville schematic that has EL3G marked on it in the output stage and it is biased to suit an EL3NG or EL33. 150 ohms as the cathode resistor. Maybe they just couldn't make up their mind what number to put on and came up with EL3G. An EL3 is a P base output valve equivalent and would not have an octal base.

If your radio is set up with a bias resistor in the cathode then the value will tell which valve should be used. 150 ohms would be for an EL33 / EL3NG and 500 ohms for a 6F6.

The EL3NG / EL33 is quite a high gain valve compared to a 6F6 so I am not surprised the audio is down if you should have an "EL3G" in the socket. A 6V6 would be closer in bias to the "EL3G" than the 6F6 and would be a better substitute just on that basis alone. The 6F6 would normally be drawing a heck of a lot more current than it should if it was in good order. If you were to put a 6V6 in it make sure you have around 300 ohm cathode resistor or -12 volts on the grid (based on the typical 250 volts plate voltage) otherwise you will stress the valve.

All of the mentioned valves have the same socket connections so they would just plug in. A 6F6 that was down to less than 50% would probably bias up about right, and maybe that is what happened. Lots of Brevilles used 6F6s so maybe someone just put a dead 6F6 into the output socket and it sort of worked.

Regards, Frank.

I am still betting on that being a EL33G. Its behind the Transformer . Usually the Rectifier and output valve are together behind the transformer. I just saw the photos. Definitely says EL3G which doesn't show up in radiomuseum. I did just recently restore a very similar Breville.