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Cheap alternative to EF86

Shoog

Member
2002-08-15 10:16 pm
Eire
Hi all,
I was looking for a low current small signal pentode, and in the end I found that of all the common types, the EF86 is the best for my intended purpose. The main attribute it has is low plate current and low screen current. Tubes like the 6AU6 have to high anode current.
However EF86's are rich pickings these days. Can anyone suggest an alternative which would do a similar job but cost peanuts. All obscure voltages and base types considered.

Shoog
 
Check out this post I did yesterday on Audio Asylum:
http://www.audioasylum.com/audio/tubes/messages/20/202741.html

For anyone using the EF86 pentode, NOS tube prices have been rising! What to do? There are new production tubes out there - the discontinued Svetlana EF86 which has a hard brittle top end. The EH EF86 is pretty good, though it seems to lack some music 'color', reminding me of solid-state. I have to hear the latest JJ version - prices are still high on this model.

Back in 1948, Philips introduced the rimlock EF40 tube which was the precursor to the EF86. This tube was used in several pieces of Siemens theater gear and in Philips radios. What makes the EF40 different than the EF86? In this case it is just the base - the EF40 (along with several other excellent tubes - notably the ECC40) uses a B8A socket. The B8A or rimlock socket uses a nub on the side of the tube which centers the tube in the socket. Kind of neat bit of engineering and also forces good contact with the pins. The B8A rimlock socket was eventually discontinued as the majority of small tubes went to U.S. standards. Therefore B8A tube sockets are available mostly through European dealers and can also be found on Ebay. Avoid the Chinese sockets as they do not have the metal outside base to center the tubes.

*I shall make a small note that the inter-electrode capacitances are slightly different between the EF86 and EF40, but not enough to make a difference at the audio level.

Who manufactured the EF40? Sorry - no Telefunken here - just Philips (branded Mullard, Valvo, etc) from Holland and (seems to be mostly) France. Earlier versions were made in the Netherlands while perhaps production was quickly be moved to France. Later 60s production was made by Tungsram. There are also Siemens versions out there but I have yet to hear a pair and I've suspected they are actually Philips since they have the same look. I do have a single Siemens supposedly made in Germany - I would like some further confirmation on this.

Best sounding are the Holland versions followed by the Tungsram. In general the French versions seems to lack the last bit of finesse of the Holland ones - and I've found this true even for EF86s - but the French versions are still very good. Tungsrams have good slam and have excellent dynamics. All versions seem to be very low in microphonics - perhaps it is the rimlock socket holding the tube tightly.

Going prices of the EF40 make them bargains! I've paid anywhere between $2 to $8 each. Provided the socket to be replaced is hardwired, it would only take a little work to convert to use the EF40. Not many of these show up in the U.S, but Canadian and European sellers have them and would be happy if you took them off their hands.
 

Gordy

Disabled Account
2006-11-02 6:15 pm
Shoog said:

However EF86's are rich pickings these days. Can anyone suggest an alternative which would do a similar job but cost peanuts.

Shoog

Right now...
http://cgi.ebay.co.uk/EF86-Electro-Harmonix-Amplifier-Valve_W0QQitemZ170178853770QQcmdZViewItem

UK seller

£9.99

49 available

Surely that's not expensive.


(No commercial interest, just trying to help...)



kstagger said:


...the discontinued Svetlana EF86 which has a hard brittle top end.



...oh for goodness sake...
 

7N7

Member
2003-01-18 10:43 pm
England
Best sounding are the Holland versions followed by the Tungsram. In general the French versions seems to lack the last bit of finesse of the Holland ones - and I've found this true even for EF86s - but the French versions are still very good. Tungsrams have good slam and have excellent dynamics. All versions seem to be very low in microphonics -

This is quite amusing too. What is "slam" exactly?

7N7
 

7N7

Member
2003-01-18 10:43 pm
England
SY said:
And with Don Byas, don't forget. Byas is sadly neglected and ought to be thought of in the same league as Bird or Trane.

Anyway, my apologies for bringing up music.;) I've got a couple Holland EF86 that have been waiting for 20 years for me to use them in something.


Sorry, I don't know anything about Byas (Bias is less of a problem...)

But EF86 is not a "good valve" - I promise you, 6BR7 is better - and 6BS7 is probably better still

7N7
 

Shoog

Member
2002-08-15 10:16 pm
Eire
Thanks for all the ideas.
I especially like the pointer to the EF40, thats my kind of tube - thanks Kstagger. I also will look into the 6BR7.

As anyone who follows my input to the forum will realise I am an extreme Frugophile. I therefore can see little benefit in using "popular" valves when more obscure alternatives exist. Fashion has been the ruin of the HIFI hobby.
Many of the EF86's are not excessively expensive at the moment, but they are popular and no longer in production, thats a recipe for prices to continue rising to the sky. Since these valves should last for at least 5yrs, next time I need to go looking for a replacement they could be painfully expensive. Why bother with the stress when choosing something like the EF40 can keep me in cheapsville for ever !!!

Remember there is rarely any sound penalty to be had from keeping to obscure cheap components, if you apply a bit of intelligent judgement that is.

Shoog
 

rdf

Member
2004-06-21 8:04 am
big smoke
Wow 7N7, you' weren't kidding. Those look like spectacular tubes. Popularity doesn't always means performance I guess. BTW, having measured the distortion spectra of enough EL84s (for example) from different manufacturers I don't find anything odd about kstagger's description of top end performance differences between EF86s. It's hard to tell an EH EL84 and JJ EL84 were meant to be the same tube from the results.
 
Shoog said:
Since these valves should last for at least 5yrs, next time I need to go looking for a replacement they could be painfully expensive.

Call me paranoid, but any time I build something that I like and that uses a cheap tube (and everything I build uses a cheap tube), I tend to buy up enough for a lifetime supply. I just finished up a DAC that uses a quad of 6688's, so I bought these -- the whole box cost less than the output transformers. That should get me ~80,000 hours of enjoyment.

Anyway, isn't the 5879 the same as a EF86, but for $8?
 

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7N7

Member
2003-01-18 10:43 pm
England
rdf said:
Wow 7N7, you' weren't kidding. Those look like spectacular tubes. Popularity doesn't always means performance I guess. BTW, having measured the distortion spectra of enough EL84s (for example) from different manufacturers I don't find anything odd about kstagger's description of top end performance differences between EF86s. It's hard to tell an EH EL84 and JJ EL84 were meant to be the same tube from the results.


Brimar said that 6BR7 and 6BS7 (version with top cap g1 connection) are especially designed to be low noise, always a problem with pentodes. I once had a Marconi ultra-high impedance valve voltmeter (input Z > 90M) this used 6BS7s which suggests that Marconi were being extra careful!

Anyway the 6BR7 is recommended as a replacement for the EF86 in Quad IIs which is why I did it, and I think that it does sound better - and I still have to optimise the operating conditions after which I expect it to be better still.

I have never claimed to have "golden ears" but I cannot tell the difference between EL34s, 5881s and 6L6s in my Quads! There is no apparent difference electrically when run in the amplifiers, and yes I know what the curves say. Suffice it to say that I have used the same cathode resistors throughout.

7N7