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Dyna-Quik Model 700
Dynamic Mutual conductance TUBE TESTER
B&K Manuafacturing company
Anyone familar with this tube tester?
Thanks.
Follow Ups:
FYI: The TubeSound website has an article about the B&K 700 tester along with its brother the B&K 707. Operation and performance attributes are described.
I haven't done any of the upgrades, but have tackled pretty much everything else.
Definitely concur with using only NOS #55 bulbs. Didn't solder them in though.
I have back up #83 internal tubes which unfortunately cannot be tested on the 700 model. Not sure about 707? Option is to purchase the solid state version of the #83.
Thanks for sharing this article.
Cheers!
Honesy
"I know just enough to get into trouble. But not enough to get out of it."
I have a model 700 since 2000 .
It's a reliable tester for 12 a.. tubes ;less reliable for russian
6922 and e88cc .
Not very useful for power tubes (unless you only want to check
shorts )
Anyway for power tubes you have to check them for real plate
Ip if you want a picture of the real world (450-500 v).
In my experience ,if you want a serious matching ,you need
3 different testers (gm,mu,Ip ,microphonics).
That's why reputable dealears ask premium prices for common
selected tubes (it takes a long time and high rejects percentage )
What are you trying to find out?
Cheers!
Jonesy
"I know just enough to get into trouble. But not enough to get out of it."
Well you own one whats your take on it is it nice? And what was the price?
Much appreciated.
Take it light,
It's "nice" enough for me.
Based on the assumption you are new to tube testers, I would deem this model a moderately priced all purpose easy to use tester.
It's a mutual conductance tester that will test tube strength, life, shorts, emission.
Note that it does not test gm (ie cannot be used for tube matching).
I bought it in 2007 off eBay for $114 US plus shipping.
When received, I replaced some internal parts, cleaned all switches, sockets, and purchased some back-up tubes (which as it happens, it runs on internally).
I don't know what one in the shape mine was would sell for now. (More/less?)
Also, testers require calibration to work properly. In the case of the B&K 700 you'll need to purchase some caps, resistors, and be able to use a DVM to do the calibration. Ensure you get the operation manual along with a booklet showing what values tubes should test at on this model. (Make sure it has settings for the tubes you use.)
If you're not a do-it-your-selfer, you can probably find one that has all the aforementioned done to it already.
My decision to purchase this brand and model was based on web research.
I've attached a link for one of the most candid, though greatly respected, sites around. Highly recommended reading along with any info you can gain by searching this forum.
Hope this helps.
Cheers!
Jonesy
"I know just enough to get into trouble. But not enough to get out of it."
This may be a stupid question but doesn't matching refer to what the tube reads at? If you test a dual triode and both section test at 98 percent would they not be matched?
Section Matching
Yes, I would consider both sections "matched" at 98 percent of that one tube.
Tube Matching
Tube strength (percentage) for "pairs" or "quads" is not enough to match true technical characteristics. For that you need to know "Mu (voltage gain), Gm (transconductance) and Rp (plate resistance)". I'm in over my head trying to explain it. So I've provided a (link) fairly decent article on it (with no affiliation to the dealer).
To be honest, when it comes to tube matching, I myself rely on best guess for triodes, making sure brand, date code and sections match. In theory, they may not be truly technically matched pairs, but good enough for my personal use.
Pentodes I leave to the experts to provide proper matching specs.
Much discussion on this forum regarding section and especially the definition of tube matching.
Cheers!
Jonesy
"I know just enough to get into trouble. But not enough to get out of it."
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