trond
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Post by trond on Apr 9, 2020 7:49:41 GMT -7
Hi I got a secondhand Maz that had JJ EL84 tubes in it. Now i have blown two pairs of JJs. I see that the recommended tubes are 6N14N tubes. Do you think that will solve my problem? I got my hands on a set of Mazda 6N14N tubes.
Or should the JJs be good enough so as my amps problem is elsewhere?
T
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trond
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Post by trond on Apr 9, 2020 7:53:52 GMT -7
An additional comment; my tech says the voltage to the tubes are above 6,3V and is the reason they blow. Could this be better with the 6N14N tubes?
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Post by Russell B on Apr 9, 2020 8:23:09 GMT -7
The JJs may have been a bad batch. Most Z amps have higher voltage. The 6N14Ns will handle it as well as a good set of JJs.
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Post by perryr on Apr 9, 2020 22:52:38 GMT -7
An additional comment; my tech says the voltage to the tubes are above 6,3V and is the reason they blow. Could this be better with the 6N14N tubes? That is the heater voltage, it needs to be in the correct range which is the same for all EL84 tubes. Im guessing its outside USA? verify source voltage and any transformer output is correct.
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trond
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Post by trond on Apr 9, 2020 23:41:06 GMT -7
An additional comment; my tech says the voltage to the tubes are above 6,3V and is the reason they blow. Could this be better with the 6N14N tubes? That is the heater voltage, it needs to be in the correct range which is the same for all EL84 tubes. Im guessing its outside USA? verify source voltage and any transformer output is correct. Yes it is outside USA. It is in Norway and the electrical network is from 220-240V. I am not sure if its a tube problem or a faulty power transformer.
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Post by steiner on Apr 10, 2020 6:53:21 GMT -7
Try a variac?
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trond
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Post by trond on Apr 10, 2020 7:50:40 GMT -7
Yes, got a Metrel. Hope it will work out, but more to carry around at gigs though. It might be a faulty power transformer in the amp that sends to much voltage to the output tubes. I use the variac now to make sure the amp only gets 210V as it at that voltage sends 6,3V to the tubes.
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Post by purpletele on Apr 10, 2020 8:26:00 GMT -7
I have two amps that have a higher heater voltage than 6.3V. I believe the voltages start at 6.6V and eventually go down by the end of the string. I was alarmed by the voltages but was informed that there is only a .3 V difference in the heater voltages. That is a nominal voltage, 1/3 of a volt.
I don't know what your heater voltage is reading, but if it is less than 1/2 volt you might be going down the wrong path, maybe not.
Just additional info
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trond
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Post by trond on Apr 10, 2020 9:33:53 GMT -7
I have two amps that have a higher heater voltage than 6.3V. I believe the voltages start at 6.6V and eventually go down by the end of the string. I was alarmed by the voltages but was informed that there is only a .3 V difference in the heater voltages. That is a nominal voltage, 1/3 of a volt. I don't know what your heater voltage is reading, but if it is less than 1/2 volt you might be going down the wrong path, maybe not. Just additional info Thanks! What tubes do you use in those amps?
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Post by purpletele on Apr 10, 2020 9:53:03 GMT -7
I have two amps that have a higher heater voltage than 6.3V. I believe the voltages start at 6.6V and eventually go down by the end of the string. I was alarmed by the voltages but was informed that there is only a .3 V difference in the heater voltages. That is a nominal voltage, 1/3 of a volt. I don't know what your heater voltage is reading, but if it is less than 1/2 volt you might be going down the wrong path, maybe not. Just additional info Thanks! What tubes do you use in those amps? Those amps are AB763 based, I am using 6L6's
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Post by easyed on Apr 24, 2020 18:34:49 GMT -7
Thanks! What tubes do you use in those amps? Those amps are AB763 based, I am using 6L6's Now I'm really confused. 6L6 and EL84 tubes won't fit in the same sockets. Both tubes are spec's with the same 6.3 Volt filament voltage, but that's about where the similarities end. If you are using 6π14π Russian military tubes, then we would have a firm basis for discussion.
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Post by zpilot on Apr 25, 2020 18:45:59 GMT -7
I have a couple of vintage amps that were built when the standard line voltage was 117vac. They just sound better when operated at that voltage than the current standard which around here averages 127vac. Go figure. One of them specs 6BQ5's for power tubes, essentially EL84's. When running at 127vac the plate voltage is 400 volts or more. That can't be good. So I feel much better running it at the correct lower line voltage. I never bothered to check the filament voltage though. I also now have 6n14n tubes in it which, I have been told, are more tolerant of higher than normal voltages. All has been well so far. I did not want to lug around a variac so I built a voltage reduction box that lowers the voltage either 6% or 12%. They are pricey to buy but relatively cheap to build.
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Post by DRZ on Apr 26, 2020 2:17:52 GMT -7
Hi I got a secondhand Maz that had JJ EL84 tubes in it. Now i have blown two pairs of JJs. I see that the recommended tubes are 6N14N tubes. Do you think that will solve my problem? I got my hands on a set of Mazda 6N14N tubes. Or should the JJs be good enough so as my amps problem is elsewhere? T Get a matched set of medium grade Russian 6n14n's for your MAZ 18 and all should be fine. What exactly is the Filament voltage on the EL 84's, they will tolerate by spec +10% or very near 7 volt AC on pins 4 & 5. When you ask a tech for a reason for a fault they will find an answer to tell you , even if it's not 100% correct. Do you have an older export MAZ18 NR , one with a DRZ-5001-230V unit ? If so what is the input wall voltage you're feeding it ? I feel this maybe your issue. If so Russian Military 6n14n's will fix that . DR.Z
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trond
New Member
Posts: 7
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Post by trond on Jul 29, 2020 3:04:49 GMT -7
Hi I got a secondhand Maz that had JJ EL84 tubes in it. Now i have blown two pairs of JJs. I see that the recommended tubes are 6N14N tubes. Do you think that will solve my problem? I got my hands on a set of Mazda 6N14N tubes. Or should the JJs be good enough so as my amps problem is elsewhere? T Get a matched set of medium grade Russian 6n14n's for your MAZ 18 and all should be fine. What exactly is the Filament voltage on the EL 84's, they will tolerate by spec +10% or very near 7 volt AC on pins 4 & 5. When you ask a tech for a reason for a fault they will find an answer to tell you , even if it's not 100% correct. Do you have an older export MAZ18 NR , one with a DRZ-5001-230V unit ? If so what is the input wall voltage you're feeding it ? I feel this maybe your issue. If so Russian Military 6n14n's will fix that . DR.Z Hi. I've got a Maz produced in 2016. The input voltage in Norway is up to 240V.
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trond
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Posts: 7
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Post by trond on Jul 29, 2020 3:09:10 GMT -7
Hi. I've got a Maz produced in 2016. The input voltage in Norway is up to 240V.
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