I have a VHF tuner with a broken ECC86. One side is a grounded grid amp and the other side the local oscillator. Both seem to run at 25V. Can I replace with a ECC88 which I have?
The ECC88 might not work well at such a low voltage. Plug it in and try it. 25 volts won't hurt it.
S.
S.
As ECC86 and ECC88 don't have anything else in common than the heater data and the pinout, I'd also recommend buying a genuine one. Remember that ECC86 is part of a set of European tubes dedicated to run directly off the car battery, not with the help of a vibrator or something like that.
Best regards!
Best regards!
Cheers, ECC88 worked perfectly both oscillator and front end - did not need to retune anything either. Don't seem to have lost any sensitivity maybes the gain is a little lower but the NF better.
This is not true. The strong similarity between PCC88 and ECC86 has been described already at the ECC86 product launch, at page 3 of Funkschau 1/1958 magazine. This issue is currently available on the worldradiohistory web site. According to Funkschau, the design goal of ECC86 was to use the exact same circuit of the ECC85 tube, but at car battery voltage. They apparently reached the goal by making slight changes to the PCC88 design: increasing the gain and qualifying the operation on the -0.4V grid curve instead of -1.2v. ECC86, ECC88 and PCC88 look indeed the exact same tube by visual inspection, differences are minor and internal (such as different filament voltage for PCC88). Some of the late '50 European car battery tube lineout seems to have been rushed out to react at the impending transistor revolution. The manufacturers spent as little efforts as possible, As example, the ECH83 tube is the exact same as ECH81 but with a different stamping on the glass. I was guessing that the oscillator section would maybe not work when putting a ECC88 in place of the ECC86 due to lack of gain, but baudouin0 prowed that this is not the case.
That are some considerable differences but when you put them next to eachother they all look the same 🙂 As you probably also hear read ECC86 also asked for extreme tight production tolerances.
FWIW I have 1964 ECC86 Siemens for sale (NOS/NIB) in the Swap Meet. Not cheap, for cheap and used one better goes to Ebay, Aliexpress etc.
FWIW I have 1964 ECC86 Siemens for sale (NOS/NIB) in the Swap Meet. Not cheap, for cheap and used one better goes to Ebay, Aliexpress etc.
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Indeed they have differences; I now clarified this in my post. My point is: they are sligthly different implementations of the same design, as the visual similarities suggests; they aren't different designs. I guess that it may also be possible to run ECC86 at higher voltages. This is something I will try when I will find a worn-out ECC86 that may be sacrificed.