Quicksilver 8417 conversion

[Original Burnedfingers]

Has anyone had their 8417 amplifier converted to use EL34's?
I read where the front end was changed to 6922's I believe.

Would it be possible (voltage wise on the plates) to stick in some EL34's without changing the front end?

[anatech]

Hi Burnedfingers,
The 8417 has a 35W plate for one, and it's a beam power tube instead of a pentode. One pair is good for 100W output. I don't think it's a good idea to try.

Here is the data page from Duncan amps for you.

-Chris

[Andrewbee]

Its not a EL34 conversion but a more appropiate one perhaps


http://www.triodeel.com/8417.htm

[anatech]

That lists the EL34 as a possible, but I'd run from that idea if I were you, KT-88 and 6550 are better choices by far. Of course, mod it for reliability and stay with 8417's. I like the 42W plate of the KT88 the most, and the high plate voltage.

-Chris

[SY]

I'm in total agreement with Chris's remarks. 6550/KT88 sort of stuff is a much more appropriate replacement. An interesting possible dark horse (it will take some clever mechanics and a rework of the power supply) is a triplet of EL84.

The 8417 was always a twitchy, unreliable, and inconsistent tube- with its unusually high sensitivity, how could it be otherwise? Like a classic Triumph, they were fine when they worked, but they didn't always work.

[Andrewbee]

Like a classic Triumph, they were fine when they worked, but they didn't always work.

You know, if I did'nt know better I would take offence.
"Classic Triumph" Is there any other Triumph?

"when they worked" they always worked when they started!

"they didn't always work" OOOohhhh please. They always worked when they wanted to!

Its a wonder you didn't type something like "they leaked oil like a sieve" .

I also notice you not mentioning BSA, Hmmm. I guess you are partial to those

Happy Friday

Andrew

[SY]

A Trump 750 scarred me for life and convinced me that "British engineering" was an oxymoron. No personal experience with BSA.

[anatech]

Hi Andrew,
Actually, I was tempted to respond that they rusted very quickly here in southren Ontario. And they really did. Positive ground + salt + water = no car. Many ex-Triumphs over here.

Beside a Harley motorcycle, nothing anyone could produce would leak oil like a sieve! Many Harleys in California. That's why no one notices!


-Chris

[Andrewbee]

okay, I am now back on topic.
I found this a couple months ago and being at the office could not remember where but now that I am at home I found the print out, googled it and found the cache of it here. Makes fun reading.

http://64.233.161.104/search?q=cache...=en&lr=lang_en

















http://www.diybanter.com/q-t_37738-Re-Bogen-amp-8417-tubes-blow-up-want-my-6550-mo-100s.html]here[/URL]

[Original Burnedfingers]

After reading this on the "Quicksilver" site it prompted my question.

For $250/pair (plus cost of new tubes), we can modify your amplifers to use EL34 output tubes by changing the front end circuitry and the bias circuitry. We also replace the 12BH7 with a 6922.

Thanks for the input and I will leave my amps as they are.