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Old 11th May 2009, 09:33 AM   #781
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Hey Gingertube and Adamus,

I really enjoy the JJ ECC803S soundwise but like all JJs products they are very inconsistent. You couldnīt do without your AVO if wanting to go JJ.

Speaking of Australian plants I bought a stash of Australian made NOS Tungsram ECL86 at eBay about a year ago. I use them as reverbdrivers in our guitar-amps. Also planning a miniature PP Schade-feedbacked poweramp that differs somewhat from the "BH".

Gingertube: Do you know anything about the Tungsram factory?

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Old 12th May 2009, 12:15 AM   #782
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Location: Adelaide South Oz
Lars,
I think they were probably re-badged. A lot of Tungsram stuff was.
My knowledge is incomplete but I know of only two valve manufacturing plants in Australia (there may have been more).

The Philips Hendon Factory, Alberton (a suburb of Adelaide) South Australia. - Tubes had a factory code of "PDA" on them.

The AWV Factory in Sydney, tubes had a factory code of "SDA" on them.

So if your ECL86 have either of these codes you know where they came from - otherwise I have no idea. I've maybe a dozen of Australian made ones on the shelf but labeled 6GW8. I'll have a look when I get home to see what the factory code on them is.

Keep us informed of your progress with the ECL86 Power Amp - They are a fantastic tube. Why the modern production "powers that be" (PTB's) decided to re-make the ECL82 (6BM8) instead of the ECL86 I'll never know.

As far as guitar amp reverb drivers go I prefer push pull 12AT7 an idea "borrowed" from Kevin O'Connor.

Cheers,
Ian
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Old 12th May 2009, 07:51 AM   #783
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Hey Gingertube,

Thanks, will check the markings on the ECL86.

Triode-driver stinks compared to pentode !
Try for yourself, you can use a std Fender reverb tranny. Easy to test with an EL84 at ca 20mA/250-300V and 1k SG resistor w/o decoupling cap.
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Old 16th May 2009, 07:01 AM   #784
adamus is offline adamus  United Kingdom
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hope i am not being thick here, but is this tthe right interpretation for gingertubes mods?

Click the image to open in full size.
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Old 16th May 2009, 02:22 PM   #785
jkeny is offline jkeny  Ireland
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I have the original "original" ECL86 BH but without UL taps on the O/P trafo so I guess I can't try this mod? However, my trafo has 8 ohm & 16 ohm taps on the secondary & I have some vague recollection of these taps being used in a pseudo UL mode - anybody know this usage & would it be applicable here?
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Old 16th May 2009, 06:13 PM   #786
adamus is offline adamus  United Kingdom
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anyone confirm my diagram is correct? If so i'll try this tomorrow, kiwames came in the post today.
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Old 17th May 2009, 11:42 PM   #787
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Yes - almost right. Take the feedback connections (the ends of teh 10K resistors) to the other side of the EL84 screen resistors - that is, to the ultralinear taps themselves.
- I've got the original Baby Huey wired like this running the HiFi System at the moment.

That is because the the later fixed biased monoblock versions are on the bench having the 12AX7 twin triode diff amp front end replaced with a 2 off 6BR7 pentode diff amp - just too see how it sounds.

Cheers,
Ian
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Old 18th May 2009, 06:04 AM   #788
adamus is offline adamus  United Kingdom
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Thank Ian!
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Old 18th May 2009, 07:08 AM   #789
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Quote:
pentode diff amp
Hi Ian,
Now you are on the right track if going for plate to plate feedback. The 6BR7/EF86 might be a little wimpy though.

Better to go for a E180F or E280F. You could also go for a cascoded ECC88 as it has about the same chracteristics as a pentode.

I used EF86 as input tube in my guitaramps earlier. They are now ECC88........
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Old 19th May 2009, 04:35 PM   #790
adamus is offline adamus  United Kingdom
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as i am running my B+ slightly high (330v) and its ultralinear, i think i am right in saying my g2 voltage is out of spec (basically 330v).

How bad is this for the el84's, should i look to reduce the B+, or shall i just live with it?
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