Hi, I'm checking some 6h30n-dr valves of my bat vk51se preamplifier with an EICO MODEL628 tube tester with the specifications of the 6922 valve and they all give me good in the area of more than 80 life, but when I put them in it makes me noise when lowering and raise the volume or mute or change fonts.
I've bought macheted sovtek valves and they don't make any noise, but the sound isn't as good as the DRs.
Would there be some way to find out which valves are wrong with the EICO tube tester or in some other way.
I've bought macheted sovtek valves and they don't make any noise, but the sound isn't as good as the DRs.
Would there be some way to find out which valves are wrong with the EICO tube tester or in some other way.
In what way do the Sovteks not sound as good? How many hours have you put on the Sovtek tubes? In my experience they need at least 100 hours for their sound to "settle in".
S.
S.
Analog_SA asked you the correct question -- does your tester test --H/K insulation --when the heater voltage is applied to the tube ??
By a co-incidence I was just testing a 6SN7 it tested 2.3 Gain so was only slightly down from 2.6 Gain ( ma/V ) BUT it tested only 10 Meg H/K insulation which I guarantee would be noisy.
Your tester only has a neon light to signify a short circuit-----not good enough it might not light at a high resistance .
By a co-incidence I was just testing a 6SN7 it tested 2.3 Gain so was only slightly down from 2.6 Gain ( ma/V ) BUT it tested only 10 Meg H/K insulation which I guarantee would be noisy.
Your tester only has a neon light to signify a short circuit-----not good enough it might not light at a high resistance .
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You can't test the noise of a tube with a such tester ... which is not necesary heater-cathode insulation . The noise is tested in circuit with modern equipment or just listen .
It sounds like the DR is drawing a little grid current, unless it is really bad I would probably ignore it.
I generally prefer EV grade for most types and found much greater parametric spread in 6S3P-DR than I did in 6S3P-EV for example. The DR has longer service life and is more rugged than the EV, but may have relaxed performance of some other parameters.
I generally prefer EV grade for most types and found much greater parametric spread in 6S3P-DR than I did in 6S3P-EV for example. The DR has longer service life and is more rugged than the EV, but may have relaxed performance of some other parameters.
Miguelnoda-- my Avo MK4 VCM tests ALL the electrodes individually --BOTH in no heater current applied and heater current applied .
In answer to "it might not be the H/K -in that particular test ALL the other electrodes are strapped to the Cathode --tests are done at DC on an extremely sensitive meter giving very good scaled information I can watch the insulation change in relation to the temperature of the cathode applied by the heater.
Sometimes it can restore back to a high resistance - IE- Infinity if the tube has not been used for decades but generally an insulation value of 10 Megohms is recognised as a "low " value .
While Avo,s are dear there are American tube testers that will be better than the tester you have at a cheaper value.
This type of test is vital in a good tester not just a "shorts " indicator light.
In answer to "it might not be the H/K -in that particular test ALL the other electrodes are strapped to the Cathode --tests are done at DC on an extremely sensitive meter giving very good scaled information I can watch the insulation change in relation to the temperature of the cathode applied by the heater.
Sometimes it can restore back to a high resistance - IE- Infinity if the tube has not been used for decades but generally an insulation value of 10 Megohms is recognised as a "low " value .
While Avo,s are dear there are American tube testers that will be better than the tester you have at a cheaper value.
This type of test is vital in a good tester not just a "shorts " indicator light.
To emphasize this there is currently an old Taylor 45C valve tester for sale online at £375, I used to have one but kept the meter display even a cheap tester like that has a graduated insulation scale on its meter ,and guess what ?--- its top reading is 10 meg ohms so even they recognize that 10 meg ohms or under is a fault condition.
The emission capability of the 6H30N-DR is way higher than that of the 6922 (a good indicator is the filament requirement which is 825 mA for the 6H30N-DR against only 300 mA for the 6922).
Since the Eico 628 is a emission type of tube tester, the results of testing your 6H30N-DR's like a 6922 will mean very little (and if so, I would think that the score of 80 % means that they are pretty bad; I would expect the meter to go off the scale when testing a good 6H30N-DR like a 6922).
What you could try is to find a tube type on the tube list of your Eico 628 that resembles the data of the 6H30N-DR as closely as possible and than test it like that type. That will ofcourse not cure the noise problems you are experiencing but maybe it will prove that your 6H30N-DR's are at their end anyway.
Since the Eico 628 is a emission type of tube tester, the results of testing your 6H30N-DR's like a 6922 will mean very little (and if so, I would think that the score of 80 % means that they are pretty bad; I would expect the meter to go off the scale when testing a good 6H30N-DR like a 6922).
What you could try is to find a tube type on the tube list of your Eico 628 that resembles the data of the 6H30N-DR as closely as possible and than test it like that type. That will ofcourse not cure the noise problems you are experiencing but maybe it will prove that your 6H30N-DR's are at their end anyway.
I have also bought 8 6n6p tubes but I am a little afraid to put them in and the preamplifier will break down as they speak so highly of them and say they are substitutes for the 6h30p DR.
I am intrigued , could somebody tell me apart from the high gain etc why anybody in their right mind would pay =$350 bucks 250 euros + shipping for a tube --solid gold grid elements ?
As far as I know Ukraine dealers are doing a roaring trade in old Sovtek military stock either selling direct or selling to Western dealers.
The UK has military equivalents a lot cheaper.
Looking on a Polish website the gain of a 6N6P is just over 11ma/V which is lower than that devastatingly expensive =6H30N- even so in your tube tester it will be well in the "good " area .
As far as I know Ukraine dealers are doing a roaring trade in old Sovtek military stock either selling direct or selling to Western dealers.
The UK has military equivalents a lot cheaper.
Looking on a Polish website the gain of a 6N6P is just over 11ma/V which is lower than that devastatingly expensive =6H30N- even so in your tube tester it will be well in the "good " area .
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BAT was quite fond of them back when they were $20. The mystique has driven the price to unreasonable levels. PartsConnexion sometimes has them for less.
Miguel,
The 6n6p is rated at a bit less dissipation than the 6H30. It also draws a bit less filament current. Probably safe to try in your amp. I don't think it could do the amp any harm to try them.
S.
The 6n6p is rated at a bit less dissipation than the 6H30. It also draws a bit less filament current. Probably safe to try in your amp. I don't think it could do the amp any harm to try them.
S.
The 6n6p does not sound like a 6n30p. It seems there are those who even prefer it but that is strictly personal. I seem to be happy with cheap Sovteks and in my systems prefer them to the DR because of the clearer top.
I have already received the 6H6n tubes and they sound very similar to the 6h30p-Dr much cheaper than the sovtek I bought and much better sounding and they have not given me any problem.
Very happy
Very happy