Hello

Wondering. Have anyone tried using the Substi-tube EF86 in other amplifiers
than guitar-amps?

More specifically I want to know if it's possible to use in a Mullard 5-10
amp where the EF86 is directly coupled to the fase-inverter (common cathode
w. ECC83). How about a Quad II, which also is another totally different
design than guitar-amp, then?

Of course I could just order a pair to try/messure. But if it's not working
it'll be an expensive experiment.

Unfortunately I can't find much data on the Substi-tube EF86 anywhere.

- Morten

best to not ever use tubes by Groove-Tube, Fender, Mesa, Philips ECG,
Sovtek, or anything Chinese - if you care about tone! or if you want long
tube life!

stick with vintage Mullard, Telefunken, RCA, etc.

Hi François,

Anyway, good EF86's or their Russian equivalent 6X32
are quite easy to find, why bother with an expensive gizmo?

I would like to add PF86, which is a 300mA series heater
version. Usually _much_ cheaper than EF86. Put a 5,6 ohms
resistor in series with the heaters, or, even better,
use a DC CCS supply (LM317 comes in handy).

Maybe 2 years ago I payed only about 20 Euros (plus
4,70 Euro shipping) for two dozen NOS/NIB 1st class
Lorenz brand PF86 on German Ebay. They have mesh plates
and look nice since you can see the cathodes glowing.
What a bargain.

I also have a few Russian 6Chi32Phi you mentioned and
I can confirm that they are a good bargain.

Tom

--
A consultant is a man who knows 40 ways to make love,
but doesn't know any women.

Morten wrote:

Hello

Wondering. Have anyone tried using the Substi-tube EF86 in other amplifiers
than guitar-amps?

More specifically I want to know if it's possible to use in a Mullard 5-10
amp where the EF86 is directly coupled to the fase-inverter (common cathode
w. ECC83). How about a Quad II, which also is another totally different
design than guitar-amp, then?

Of course I could just order a pair to try/messure. But if it's not working
it'll be an expensive experiment.

Unfortunately I can't find much data on the Substi-tube EF86 anywhere.

- Morten

If that 12AX7 is hooked up as a cascode as I suspect it should be a very good
substitute for the EF86 it replaces. JLS

"John Stewart" wrote

More specifically I want to know if it's possible to use in a
Mullard 5-10
amp where the EF86 is directly coupled to the fase-inverter
(common cathode
w. ECC83). How about a Quad II, which also is another totally
different
design than guitar-amp, then?

If that 12AX7 is hooked up as a cascode as I suspect it should be
a very good
substitute for the EF86 it replaces.

Hi John,

Hmm...the Quad II links the screens. Wonder how that would pan out
with a cascode?

cheers, Ian

Morten wrote:

Hello

Wondering. Have anyone tried using the Substi-tube EF86 in other amplifiers
than guitar-amps?

Why? Isn't a real EF86 good enough?

Patrick Turner.



More specifically I want to know if it's possible to use in a Mullard 5-10
amp where the EF86 is directly coupled to the fase-inverter (common cathode
w. ECC83). How about a Quad II, which also is another totally different
design than guitar-amp, then?

Of course I could just order a pair to try/messure. But if it's not working
it'll be an expensive experiment.

Unfortunately I can't find much data on the Substi-tube EF86 anywhere.

- Morten

The Quad uses the EF86 at a low anode voltage to allow DC coupling.
Tweaking these circuits is usually not a good idea. Any good EF86 will last
about 10,000 hours, therefore, should You spend even 25$/ea (see
http://store.triodestore.com/efnostesczec.html) for some of the best ones,
this would translate into 50/10,000 = 0.5 cents per hour.
It's not that much.

Ciao

Fabio


"Morten" ha scritto nel messaggio
. ..
Hello

Wondering. Have anyone tried using the Substi-tube EF86 in other
amplifiers than guitar-amps?

More specifically I want to know if it's possible to use in a Mullard 5-10
amp where the EF86 is directly coupled to the fase-inverter (common
cathode w. ECC83). How about a Quad II, which also is another totally
different design than guitar-amp, then?

Of course I could just order a pair to try/messure. But if it's not
working it'll be an expensive experiment.

Unfortunately I can't find much data on the Substi-tube EF86 anywhere.

- Morten

Anyway, good EF86's or their Russian equivalent 6X32
are quite easy to find, why bother with an expensive gizmo?

Could be an interesting experiment. I have a set of old professional amps
which builds on the Mullard 5-10 construction but are not 100% identical.
The gain is guite high considered they're power amps and it has the EF86 as
the first stage. Så appart from the very high gain and a tiny bit of pentode
noise (listen very carefully with no signal at all - ear in speaker) the
sound is truly amazing compared to modern tube amps.
Well, I'm really not hoping for lower gain since it's easy to obtain in the
(homemade) passive preamp but if the tiny bit of pentode noise could be gone
it would be great. Perhaps having another sound to play with.
Modifying the amps is not an option though it might be easy. I want to keep
them in as near original condition as possible except for newer component
where the old ones left off - capacitors, cathode- and two compressed carbon
resistors. The other resistors are old carbon films and are still within
spec. I did however replace the coupling capacitors with polypropylene
instead choosing a paper-in-oil type like the original to get a brigther
more modern sound. And of course polypropylene compared to oil types
literally lasts forever if kept within spec.

I would like to add PF86, which is a 300mA series heater
version. Usually _much_ cheaper than EF86. Put a 5,6 ohms
resistor in series with the heaters, or, even better,
use a DC CCS supply (LM317 comes in handy).

Thanks for suggestion.
I did know that P and E valves are the same except for heaters. A friend of
mine has a kit-amp which uses EL84 and ECF80. Since the ECF80 is a bit hard
to come by (even though it shouldn't be rare) we fitted an extra trafo,
bridge and voltage regulator to power the two PCF80's (300 mA @ 9 v) which
compared are endeed very cheap and easy to come by.

-Morten

If that 12AX7 is hooked up as a cascode as I suspect it should be a very
good
substitute for the EF86 it replaces.

Thanks.
Might be worth a try then. I can order two to try them in the Mullard
likes - one for each channel.

Hmm...the Quad II links the screens. Wonder how that would pan out with a
cascode?

Yes, I'm also very currios about that. Well, if buying two for the other
more mainstream like amps with cirquits build on Mullard 5-10 (though not
100% identical) I can always try them in one Quad II to hear and messure how
it works out.

-Morten

The Quad uses the EF86 at a low anode voltage to allow DC coupling.
Tweaking these circuits is usually not a good idea. Any good EF86 will
last about 10,000 hours, therefore, should You spend even 25$/ea (see
http://store.triodestore.com/efnostesczec.html) for some of the best ones,
this would translate into 50/10,000 = 0.5 cents per hour.
It's not that much.

Don't forget that most of us use two Quad's at the same time - 1 cent/h ;o)

-Morten