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The µTracer cannot measure the vacuuum, you would have to measure change of Ia with a grid resistor and real, continuous plate voltage.

I asked the seller if he could give the full number. On the pic theres only a part visible.

Wise words. But going to skip that pair, preferring to wait for originals, no hurry at all. Thank you for your input!

Ok. What do you think is the loss of value (%) compared to original cone/condition when they play nicely although they are reconed) ? Here in Germany it's not easy to get a good pair of 604G, I have been searching nearly 2 years for mine. Now looking for another pair for a friend (also for...

Any idea (according to the numbers on the cone) what kind of replacement was used?

Thank you. And yes, also noticed that not existing slack.

Also, the felt around the horn, looks to me kinda oversized (?)

Hey, checking a pair of 604 8G, to me the cones do not look original. Can someone give me a hint?

Looks good. When looking for data sheets, remember, Franks site might be one of the best ;) https://frank.pocnet.net/ And feel free to ask stupid questions ;)

Yeah. YW. I started at that point too, no worries. Kinda steep learning curve at the beginning, but worth it.

Oh, please forget the question about pin1 and pin6 separated, you only see 1 graph because you did choose "none" for Y2 graph. Maybe my fault, one of my screenshots puzzled you (it was a screenshot where I really measured system1 and system2 separated -using the "keep plot feature" - to compare...

Yeah, it looks like plate and screen are not separated. Are you sure that there is no connection between pin 1 and pin 6? And yes, for a new ECC83 Ia 75% seems a bit low in quicktest. Screenshot indicates that you are using the µTracer heating (?), I thought you had an external heating supply...

For ecc83/12ax7 fill in: Va1 250 Va2 250 Vg -2 Ra 62.5 Gm 1.6 mu 100 Ia1 1.2 Ia2 1.2 Ofc "Triode" not "Pentode" ;) ...thats all.

Yeah, you have to edit the blank boxes with the typical values for the specific tube you measure. Ofc you can save them.

.... you have to pick the "typical" pre settings from the tube datasheets. EG: From: https://frank.pocnet.net/sheets/010/e/ECC83.pdf

Exactly. It's -of course- also in the manual: "5) I(Va=Vs, Vg) with Vh Constant Measure Ia, Is as a function of anode voltage = screen voltage stepping the grid voltage with the heater voltage constant. This measurement type is used to simultaneously measure the output...

And btw, when measuring both curves of a double triode like 12AX7, you should choose the correct measurement type, which is: ...but, first start with quicktest and make that work before doing curves.

If you have "no Ia bar" at all with quicktest, there are only 2 possibilities: 1. No or wrong filament voltage from your external heating supply 2. Wrong connections to tube. How did you connect pins 1,2,3 and 6,7,8 to your µTracer anode, cathode, grid and screen connector?

Can you do a quicktest with correct settings for the 12AX7 .. in your screenshot there are no presettings at all: Heres a screenshot for ECC83/12AX7 from mine:

Telefunken indeed produced 6SN7. Few weeks ago there was a very, very interesting interview with old TFK guys at https://www.radiomuseum.org/forum/roehrenhandel_in_deutschland_erinnerungen_eines_insiders.html ...from this: "Wir haben auch einige US-Typen selbst gefertigt die keine europäische...

...if they have same voltage rating (or higher), yes.

Without any reasonable (dummy-)load it wasn't a test. Its about speaker outputs, not some line-out? A receiver -normally- is an amplifier + tuner, btw ..

Hello. 3 years ago friend of mine chose me as tester for a R2R ladder he made hisself, cuz I was used to "digital sound" and enjoyed my audiolab CD8300 very much. Had to build the housing, buffer stage, power supplies. Was extremely sceptical, but after I fit the assembled boards, turned on my...

Waiting for spring...

Thats the circuit for the overload warning LED attached at front of speaker.