Regulator tube

[vetmed]

Can I use an ECC99 instead of the 12bh7? Looking at the spec sheets they seem very similar with greater plate dissipation in the ecc99. Only caveat seems to be that the heater current needed is slightly higher, 800ma as opposed to 600ma for the 12 bh7. Is the power transformer up to the extra current? Thanks


Robert Lees

[Jim R.]

Good question -- I'd be interested in if this will work too.  Nice tube the ecc99.

-- Jim

[Paul Birkeland]

Looking at the two tubes, the pinouts are the same, which is very helpful.  Also, the cathode voltage of the ECC99 will be in the safe area of operation for the TL431, which is also helpful.  The ECC99 also has beefy plates that won't be bothered by the operating point. 

The one possible issue with doing this would be the additional heater current (even though it is a small increase), and I'm sure PJ can weigh in on this.

[Paul Joppa]

The increased current exceeds the capability of the heat sink in the DC heater supply. That's as I calculate it, which allows for a maximum 130v power from the wall socket. If you are close to the design value of 120v, then I don't see a problem - but if the PSU board gets brown and the regulator chip turns into a fuse, don't blame me! And be aware that the line voltage varies and can change without notice when the power company makes changes.

Remember, line power was 110v in the 20s, 115v mid-century, and a majority in the US exceed 120v today.

[Jim R.]

Well, at 124v average, I will have to let  this one slide.  Too bad -- these tubes are cheap, sound quite good and are quite beefy and can take some abuse.

Thanks both Pauls,

Jim

[2wo]

How about a bigger heatsink?

[grufti]

Hey, you're getting close to my "rusky-ros-clone". Still very much Paul's design, but using all cheapo Russian tubes: 6J9P-E [dirt cheap, plentyful, less noise than any EF86, a bit more gain], 6N23P-EV [sometimes others also dirt cheap], 6N6P in the shunt regulator [dirt cheap and works].

The 6J9P-E has a different pin-out. The others drop right in.

[grufti]

This little sample is from the original Eros with LED bias for the EF86 tubes and a 6n6p in the shunt regulator. No other changes, not even a choke in the power supply, but it does have very carefully selected EF86 tubes and tight RIAA filtering / channel balance.

This brief clip is recorded in 48kHz/24bit resolution. Play it with an application that does not resample and/or truncate and/or otherwise mutilate for best results. I'm putting this up for a day or two to show my appreciation for the best MM pre that I have ever used.

Thank you Bottleheads.

https://skydrive.live.com/embed?cid=2AB0C5509CAF303A&resid=2AB0C5509CAF303A%21459&authkey=AP79e74H_Pxy47Y

[Jim R.]

Hans,

That's a pretty bold endorsement there -- makes me want to get mine done even sooner.  I grabbed the file and will give a listen later on.

Thanks,

Jim

[Doc B.]

How about a bigger heatsink?

That's the biggest PC mount heat sink available to us.

[grufti]

I need to add a caution regarding the use of the ECC99 / 6N6P tube in the shunt regulator. My Eros never sees more than 117V AC because it gets its line voltage from a PS Audio power conditioner. That makes life easier and safer for the regulator.