Re: 6DJ8 substitute idea - reverse engineering


Tom Lee
 

My guess is that you are in the minority in declaring such a move "neither productive nor necessary." Given the absurd cost of most 6DJ8s, using 6BQ7s is often the only economically practical route to repair (or restoring to service a found carcass that has been stripped of its tubes). Scopes don't care about the things that matter to audiophiles (e.g., "noise grading"). Spending hundreds of dollars for a set of tubes to restore a scope is likely prohibitive to most. If a 6BQ7 will work in the application, I fail to see why one shouldn't use it.

--Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 6/21/2021 11:31, Liam Perkins wrote:
Or, and if you need them, you could buy current production parts from
Eurotubes https://www.eurotubes.com/store/pc/E88CC-6922-or-6DJ8-c52.htm who
can provide them curve tracer, section-to-section matched and noise graded.
They have the RoeTest curve tracer and an ex-Tek guy, Matt Kamina working
with them. They know what they're doing. Here are a couple links to the
RoeTest site http://roehrentest.de/EnglishInfo.html
http://roehrentest.de/RoeTest2.html.
I wouldn't even consider downgrading to the 6BQ7, such a move is neither
productive nor necessary.
Liam

On Mon, Jun 21, 2021 at 12:10 PM Jeff Dutky <jeff.dutky@gmail.com> wrote:

Keith wrote:
With any non-Tek prepped NOS 6BQ7 OR current production 6N23P we could
do the very same thing. Burn in and section balance measurements are
not very
difficult to do. You just have to tell yourself the truth when
measurements show
that you have to to reject six of those seemingly "economical" 6N23P.
Allowing for
waste, these seemingly less expensive tubes might suddenly "cost" you $5
or
more a pop, plus the time wasted burning in and measuring.
Of course you just turn around and resell the "failed" tubes to the
audiophools on eBay for $10 each as "burned in and tested." It wouldn't be
a lie, or even an exaggeration.

-- Jeff Dutky






Join TekScopes@groups.io to automatically receive all group messages.