Calibration on my tester is supposed to be easy. Pop in a resistor to check, that’s it.
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Here is my set up when checking 6SN7 tubes for my Darkvoice.
I press the quality button on pins 1 and 4 and it reads 94 and 97. Simple setup for peace of mind.
My tester is in great condition be careful buying these half century old antiques.
Thanks for the reply. So as long as those tubes are the same Make and model, you would consider those matched at 94 and 97?
It is close enough for me. If my ears cannot differentiate the audible difference in distortion nor the difference in gain, then I am a happy camper. Isn’t this what matters ultimately? If one is new to tube amps, the short answer is to purchase tubes from a trusted buyer that has a reputation to uphold, and pay the minor fee for matching. You will be paying for confidence. This also establishes your baseline. There is no need to venture from the baseline. However, once your ears and wallet have adjusted, you could then venture into unknown territory and see if your ears can remain happy with inexpensive eBay tubes from the unknown. It is a fun gamble that I enjoy playing because you can always return to your original trusted tubes at any point.
Yes, my take too. When I’ve run mismatched good tubes the first thing I notice is differences in volume. I’ve either improved or made it worse by swapping, as headphones and amps can have slight channel imbalances too.
When one tube is truly bad (or just worse) than the other, they can ring or hiss or sound otherwise off.
I’ve never purchased from VivaTubes but they are large and established. You should be fine with the vendor. Regarding four tubes ranging from 8400 to 8000 – put the 8200 and 8000 opposite each other. Put the 8400 and the 8400 opposite each other.
Viva sells a lot of tubes. I have one of the testers he uses (TV7D/U). He states he checks for shorts, gas, etc.
IME, most of the guys who sell a lot of tubes and tell you what type of testers they use, and give mutual conductance results are pretty bang on. For guys like me with a tester, it’s too easy for them to get called out if they sell you a dud. Sometimes they get damaged in shipment. The ones you need to be more cautious about are vendors who sell untested tubes without a return/replacement policy.
86/84% are a good match and should perform acceptably.
94 and 97 are a good match…within about 5% is generally a (Very) good match…
I have a couple of them: TV7D/U, and TV7A/U (mid50s-early 60s)…used mostly by the military of that era…
Wow! Those are super sweet! I wanted a Hickok when I was shopping for a tester but they comand big buck$. Hickok testers are not only more accurate but they are also repairable since one can find replace parts. My B&K will have to suffice.
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There are some hardcore tube enthusiasts that have created a few modern affordable Tube Analyzers (not just testers) that interface with computer applications to provide more data on a tube than you would ever need including at variable voltages. Way beyond my interests in tube measurement. However if one was inclined to follow this rabbit, search for “uTracer” for one such example.
One last question. When an online vendor says they can match tubes (usually for $x amount) do they have some special process or machine that would be able to do that with unmatched pairs, let’s say 2 GE 6W6 that aren’t matched? or are they just going through their inventory and finding two similar tubes that have matched test results within 5% or 10%?
They don’t tune the tubes. They are simply matching the tube to another tube of similar mutual conductance. The matching of microphonics is more of a subjective measure.
You can buy the older A or B variants for around $500. The D is the far better tester and will command more money. My brother is a vintage collector and rebuilt both of the testers for me. He modified the TV7A/U to work better with small signal tubes. If you buy run across one you want to buy, get the TV-7 D/U. My A works like a D.
What amp do you have now ?
He has a DNA Stellaris per his prior posts.
Update January 6Th, 2023: I spoke with Donald North today in regard to the status of my DNA Starlett, and he said that my Starlett may be ready by July of 2023. This means that it will have taken 18 months to have the Starlett built. That is if it is indeed ready by then.
On the positive side, I have moved up in the que from number 22 to 14, and Donald said that it is possible that delivery may happen earlier.
At this point I feel that I have waited for a year, so I might as well wait another six months. Just wanted to let anyone who is considering purchasing a DNA headphone amplifier know that there is a long wait; even longer than usual, courtesy of Covid related parts delays. So if you want a DNA headphone amplifier you should consider getting on Donald’s waiting list as soon as possible.
Earlier…
Donald was kind enough to let me demo a prototype Starlett for a month back in 2021 and I liked it so much with my HD6XX and HD600’s that I decided to later order one. Mine should have been delivered last month, but due to Covid and other related delays, delivery has been pushed back by a few months.
I do agree that the Starlett is an end game headphone amplifier for higher impedance dynamic headphones.
While I wait for my Starlett, I will enjoy a NITSCH Piety headphone amplifier that I purchased from CEE TEE recently. Thus far very impressed with this little gem. IMHO, the performance for $149 is unheard of.
Your patience will be rewarded. Enjoy the Piety in the meantime.
I’m almost afraid to ask but what made it take 18 months to get it?
The backlog of orders he has…
Donald North is a boutique tube amp designer/maker and afaik a one-man-show. His amps are well worth the wait.
Donald is a one man shop who builds world class headphone amplifiers. The wait time prior to Covid was a lot shorter, but Covid related supply chain issues have caused much longer wait times.
Moreover, as word continues to get out in regard to his headphone amplifiers, Donald’s waiting lists are getting longer and longer. I know of customers who’ve waited 24 months for a DNA Stellaris. I can say that his amplifiers are certainly worth the wait. You just have to understand going in that you are ordering a bespoke product that is very rare and plan accordingly. My Starlett is the most recent one built and it’s only serial number 48.
