6M5 valve

[PeteMcK]

Anyone had experience with this relatively obscure valve?
I think its an EL80, or an EL41 in a different package

I picked up an old Kriesler radiogram from the side of the road, still in working condition (turntable missing), with schematic on the back(built 1970), good 6" full range speakers.
The amps are 1/2 a 12AX7 driving a 6M5, about 3-4 watts. It has an interesting bias circuit, 'back' bias (Aitken amps has an article on this on their site), basically derived by lifting the power trannie CT above ground with a resistor.

I'm thinking of converting it to Cathode bias, and using both sides of the 12ax7 in series to make a little guitar amp, similar to a Fender champ, unless there's a collector with something to swap in the Sydney area who wants to stop me butchering the unit.

Cheers,
Pete McK

[fdegrove]

Hi,

According to what I found the 6M5 is a Mullard valve and an equivalent of the EL80.

Replacements are available at :

[fdegrove]

Hi,

According to what I found on the web the EL80 should be equivalent.

In case you need replacement :

EVATCO

Don't know about the collectors value of the Kriesler unit though.

Cheers,

[TimMason]

I had just recently bought a box of valves from a deceased estate the owner of the box was a radio engineer in katoomba NSW Australia, in the box of some 200 valves a group of MINIWATT 6BQ5s, that i was looking to identify, which ended being EL80s the next batch of valves i tried to id were Miniwatt 6M5 the unusual thing is they look identicle in construction materials shape metal pressings the lot.I have not as yet found any data, and i am no electrical engineer, just a starter who has built his first burning amp (deluxe). is it possible they are the same out of the same factory?

[darryl_h]

Some 6M5 data from the "Miniwatt Electronics Handbook", published by Philips, in Australia, in 1965.

[trobbins]

Well done darryl_h - thanks for posting that info - it provides a little more data than a simpler Miniwatt summary table I had. I should try and revisit a little Philips intercom that I restored a few years ago that has a typical 250V B+, and 7k5 OT and 6M5 cathode biased PP, even though it's got a 62 ohm output OT. I've just grabbed the EL41 plate curves at 250V screen, which can be used to more confidenly check loadline operation.

Ciao, Tim

[darryl_h]

Originally Posted by trobbins

I've just grabbed the EL41 plate curves...

All the graphical information for the 6M5 in my data book is identical to that given here: http://tubedata.milbert.com/sheets/030/e/EL41.pdf Even the title of each page has not been corrected from EL41 to 6M5.

[trobbins]

Thanks for that darryl_h, as that helps confirm. I didn't find that EL41 datasheet link, but another abridged version had the anode curves. The scottbecker site is down, which is where I normally go.

I can't identify any change in the optimal loading curves shown on pages 11 and 12 of your linked datasheet for EL41 (?), except for the dates - maybe they changed physical packaging, or moved manufacturing plant.

[gingertube]

"Relatively Obscure"
Not here in Oz at least - they were widely used in just about every locally produced "3 in 1"
stereo unit and were even used in Maton , Moody etc. Ozzie Guitar Amps.
As stated by Fred above, they are equivalent to an EL80. Not that hard to find NOS tubes and quite easy to find good used ones.



Tim, 6BQ5 are EL84 and not 6M5 equivalents. They are beefier than the 6M5.

Cheers,
Ian

[BeJay]

Hi Guys,

I'm chasing a 6M5 for my HMV "little ripper" and was wondering where in Oz (or hopefully WA) I can find a replacement. Does anyone have a link or know of where I could source one?

Thanks

Bj