E80F OK substitute for EF86?

kip.duff · 1303

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Offline kip.duff

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on: December 25, 2019, 04:24:14 PM
I bought some nice German E80F Valvo NOS tubes for Eros 2 first stage.  Based on some info in these treads, I believed they were compatible with E86F.  But I did my voltage tests- got 1.7V at OkC and OkD with kit supplied tubes- within your recommended spec of 2.0V.  With the Valvo tubes, I got 2.3V amd 2.5V.  Is this a risk running these?  Not an acceptable substitute?

Thanks, Kip..... 

Dr. Feickert Blackbird II w Reed 2A tonearm and Lyra Skala cartridge.  Eros 2.  Audio Note DAC 2.1 Signature.  BeePre with BeeQuiet and Paramount 1.1 monoblocs into A7 VOTTs or Nagoaka folded horns.


Offline Paul Birkeland

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Reply #1 on: December 25, 2019, 06:48:48 PM
I personally wouldn't use them.  They use a bit more heater current, which isn't ideal for the 6.3V regulator.  They will also have less gain and likely a little more noise than an EF86.  The linearity of the EF86 with ~100V on the screen looks quite a bit better with 1.5V of bias than the EF80 with ~100V on the screen and 2.5V of bias.

Still, the Eros 2 will function as a phono preamp using them.


Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline kip.duff

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Reply #2 on: December 25, 2019, 07:38:35 PM
Ya- didn't seem right.  Glad I asked

Thanks for response- Kip.....

Dr. Feickert Blackbird II w Reed 2A tonearm and Lyra Skala cartridge.  Eros 2.  Audio Note DAC 2.1 Signature.  BeePre with BeeQuiet and Paramount 1.1 monoblocs into A7 VOTTs or Nagoaka folded horns.


Offline kip.duff

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Reply #3 on: December 26, 2019, 04:03:13 PM
I don't know why I wound up with these Valvo E80Fs.  EF86s are affordable.  All kinds of EFT, Telefunken, Valvo NOS or "test-NOS" offers on eBay.  NOS matched pair of Bugle Boys or Mullard (Holland) under $100 pair on the high end.

Dr. Feickert Blackbird II w Reed 2A tonearm and Lyra Skala cartridge.  Eros 2.  Audio Note DAC 2.1 Signature.  BeePre with BeeQuiet and Paramount 1.1 monoblocs into A7 VOTTs or Nagoaka folded horns.