It might ? Still interested in the octal pinouts if you are able to read them..

In a domestic set as a first RF, it is more common to see 6K7 (early) 6U7 (everywhere) perhaps 6J7 Which are top cap tubes.

The Radiola passing through has 6SK7 which has the same pinout as 6AC7 but is remote cutoff....Wrong valve perhaps? And no accident.

One can muddle through without a circuit. I had an EMMCO & an AWA "Special" where I had to draw the circuit to find the miswires etc. and in the full knowledge, with both that a circuit was, "mission impossible".

Marc

Hi guys,
I just had some recent success with the Breville Precedent; a result that I was most happy with, great sound and volume. Having changed the caps I then discovered by replacing the valves that I had a lazy 6M5.
EVATCO substituted this with an EL83 result excelent.

Then nothing!
Everyhing appears OK.
Transformer outputs are spec.
Valves appear OK.
WIring has been exstensively redone
No bad smells or sparks.
The big caps I replaced again.

I think it likely that I now need to do resistors!
So far I have sustituted everything one part at a time.
Now I really need a circuit diagram.
The Number stamped into the chassis isV46087.
The Number on the sticker is 471447

Can anyone help me?

I may add that I get some hum, crackle and one faint station. The volume control changes nothing though it tests OK, 1M across, the wiper is in contact and the intermediate resistance is variable between both ends.

EL83 is a Video output pentode 6CK6 Pin 6 is grid 3 (suppressor) and is internally tied to Cathode on 6M5 but not on EL83. It is pin 6 (what is on pin 6 in that set?)

6M5 is EL80


Put the dodgy 6M5 back & see what gives if it originally made some radio noise.

Marc

Pin 6 is unwired.( looking uo from under chassis and counting clockwise). The old valve achieves a similar result, a few clackles and hum and no responce on the volume control. The EL83 worked well before the big silence. Maybe we have to meet marc?

Hopefully that valve did not bend something, running with it's suppressor floating.

Pin 6 needs wiring to the cathode pin. Check the cathode resistor & cap if fitted. Remove cap to check both.

The fact that volume does nothing suggests that the fault is in that area.

Would be easier for both of us if it was sitting in front of us. With test gear at our fingertips.


The valve most similar to 6M5 (EL80) is apparently 6CK5 (EL41). This does not have the same pinouts & the socket would need to be rewired

Marc

Hey Marc
Is the EL83 a bad choice?
Maybe I should get the alternative and then call in ?
Bill

I would email back to the source of the EL83 and ask as to why they supplied it, when it is not pin interchangeable? They really should have told you that it was not exactly the same.

I would consider it an unwise choice 6CK5 is almost identical but for the fact it's a different base. There is no data on EL83 in the Philips book, relating to it's use as an Audio amp.

It is not unusual to find RF/TV valves in Audio out. I have an Amp with 6CM5 horizontal outputs & 6BM8 is another. 6V6 has been used as a horizontal amp.

Keep Frank's Electron tube pages in mind for data.


The TV output 6GW8 is another tube very similar in characteristic, quotes the same load & mutual conductance, plate current and cathode resistor on it's Pentode. Likely the same pentode packaged with a triode? Rewire required same socket.

Very few would use it, outside TV & you may be able to get a bucket full of them cheap?

6M5's are getting scarce but there are other suppliers, perhaps try Steve Saville or someone in Melbourne

I may have a spare but I do have a Philips 132L and a Little Nipper with two workers. So one could muddle on regardless.

Marc

G'day Marc,

I've noticed over time people saying that the 6M5's hard to get though in contrast it seems like a ot of people also have radios with this valve in it.

Do you (or any other member) know why this valve is rare?

I think it comes down to the fact that once apon a time, we had a manufacturing industry in Australia.

There were a few Valves that were, or seemed to be made here and knowhere else, or only used here. 6M5 I believe was a Philips valve.

The most common output tended to be 6F6 then 6V6 with AWA later to 6AQ5.

6BM8 was very common in amps & record players & 6GW8 in TV. I often wonder why 6BL8 never had a bigger run in radio's as it was an everything type of valve.

Tasma tended to use European tubes.

We really only had AWV & Phillips making valves, so once they went by the way side, many of the valves only made here, were not logically, made elswhere.
So the only stock piles if any were here.

There are a few that hoard valves and I have a lot of TV tubes that I have been given or aquired so that they were not dumped, albeit that I will likely never use them, and rarerly manage to divest myself of any of them. Then there is the issue of the benefit to me, if any, of sorting them

I know of several instances where Valves were just trashed, as there was percieved to be no further use for them, as everything was going Transistor and they took up space in the shop.

Clearly, for someone to manufacture a run of new Pentagrids etc. It needs to be commercially viable, especially from the afordability & cash recovery point of view.

Marc

In a box of unsorted TV valves that arrived recently and just had to be shifted....... is an unknown condition 6CK6

Marc

So the 6M5 was pretty much an indigenous valve...

I have a couple of hundred baseless valves so I will have to have a look. I may be wrong but it just seems like a familiar number for a reason I cannot explain.

I just love that frequently used term "baseless" valve / tube. Oh how it lends itself to be misconstrued.

If you have a look in AORSM's HMV, Kriesler, Philips just about everyone & the dog through the fifties used them: Nearly as common as 6V6.

Marc

Well, I suppose all valves have bases, just not bakelite ones. Yes it is a common term though. Sometimes I say seven/nine pin valves but my fingers are too sore for longhand these days.

We could have the same argument about calling a valve a tube but there wouldn't be a clear winner in that debate either.

A little guidance, please re the 6AC7 pinouts - is this a matter of looking at the pin connections as they are on my Precedent?
If so, a picture may be worth a thousand words?