*Please let me know if I have posted this in the wrong place*
Hello,
I have created a little problem for myself and I'm wondering what I can do to make use of my mistake.
I'm very new to tube amplifiers, and had a Bravo Audio v2 that I wished to upgrade.
When I looked online, I believed the consensus was that the "12AU7" is also known in Europe under its Mullard–Philips tube designation ECC82, and that these tubes were interchangeable. I also saw that Bravo Audio themselves sold a variant of the V2 with a Golden Lion ECC82, so I assumed I was good to go on buying this type of tube.
I know now, after purchasing a TAD RT005 Tube 12AU7 ECC82 that this is not the case. I found this out by plugging it in and only getting signal from one channel.
I know, I'm probably the biggest idiot for doing this, but I would like to know if there's anything I can do. I have a lot of experience working with circuit boards; is there any modification I can make to the Bravo Audio v2 to make it accept the 12AU7/ECC82 tube?
If not, what's my best course of action? I'm finding it very difficult to find an answer, which is no doubt because of my lack of savvy on this topic, but I would appreciate help. Even just a basic explanation to why and how I messed up would be much appreciated.
I'm finding it hard to find an upgrade amplifier that takes this tube too.
Apologies for the dumb post but I couldn't find anywhere else to ask for help.
Glenn
Hello,
I have created a little problem for myself and I'm wondering what I can do to make use of my mistake.
I'm very new to tube amplifiers, and had a Bravo Audio v2 that I wished to upgrade.
When I looked online, I believed the consensus was that the "12AU7" is also known in Europe under its Mullard–Philips tube designation ECC82, and that these tubes were interchangeable. I also saw that Bravo Audio themselves sold a variant of the V2 with a Golden Lion ECC82, so I assumed I was good to go on buying this type of tube.
I know now, after purchasing a TAD RT005 Tube 12AU7 ECC82 that this is not the case. I found this out by plugging it in and only getting signal from one channel.
I know, I'm probably the biggest idiot for doing this, but I would like to know if there's anything I can do. I have a lot of experience working with circuit boards; is there any modification I can make to the Bravo Audio v2 to make it accept the 12AU7/ECC82 tube?
If not, what's my best course of action? I'm finding it very difficult to find an answer, which is no doubt because of my lack of savvy on this topic, but I would appreciate help. Even just a basic explanation to why and how I messed up would be much appreciated.
I'm finding it hard to find an upgrade amplifier that takes this tube too.
Apologies for the dumb post but I couldn't find anywhere else to ask for help.
Glenn
These amp operates the 12AU7/ECC82 at 24V instead of the normally 10X higher voltage for which the tube was originally designed for. Chances are the specific tube you got doesn't like to operate at 24V. I would return it for a new one.
Also plug the old tube you have back in to see if both channels are working again. This is to rule out to see if you broke some PCB traces while plug/remove new tube.
Also plug the old tube you have back in to see if both channels are working again. This is to rule out to see if you broke some PCB traces while plug/remove new tube.
You want to replace a 6922 to a 12au7 variant? 😕
Those low voltage circuits won't make it easy to any tube, actually they are working already in a non linear touchy portion of the curves, but you can make them pass maybe 500uA of anode current driving them with positive grid bias, but that will skyrocket the THD and will need a low impedance input (gross no linear grid current) also it is needed to be said a ecc88/6922 variant will run better than the one you want to "upgrade", don't even mind to use matched tubes they wont make any difference in those circuits.
If the unit has been sold for both 6922/12au7 then it must have a switch to change or something because the 6922 has a nominal 6.3V heater and the 12au7 has a centre tap heater (12.6 in series, 6.3V in parallel) if you plug a 12au7 in a 6922 designed circuit it will only light one triode assuming they solid grounded pin 9, please look for those triode/amplifiers datasheets before doing more
Those low voltage circuits won't make it easy to any tube, actually they are working already in a non linear touchy portion of the curves, but you can make them pass maybe 500uA of anode current driving them with positive grid bias, but that will skyrocket the THD and will need a low impedance input (gross no linear grid current) also it is needed to be said a ecc88/6922 variant will run better than the one you want to "upgrade", don't even mind to use matched tubes they wont make any difference in those circuits.
If the unit has been sold for both 6922/12au7 then it must have a switch to change or something because the 6922 has a nominal 6.3V heater and the 12au7 has a centre tap heater (12.6 in series, 6.3V in parallel) if you plug a 12au7 in a 6922 designed circuit it will only light one triode assuming they solid grounded pin 9, please look for those triode/amplifiers datasheets before doing more
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I found your post unintelligible so I had to Google. The V1 model uses 6922/ECC88. The V2 uses 12AU7/ECC82. 12AU7 and ECC82 are equivalent. If you have a V2 and you put a good 12AU7 or ECC82 and only hear 1 channel, you most likely did something wrong like enlarge the pins or just incorrectly inserted it. Look for a basic mistake of this sort first.
EDIT: If you have a V1 then maton00's theory makes lots of sense.
EDIT: If you have a V1 then maton00's theory makes lots of sense.
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Hello,
Thank you all for your replies, they're very much appreciated.
Something seemed off. I had bought the amp on a local sales site, which was advertised as the V2. After looking into it, I was probably scammed and sold the V1 in it's place, and I had believed I had the V2 all this time.
Thanks for your patience and detailed replies.
Thank you all for your replies, they're very much appreciated.
Something seemed off. I had bought the amp on a local sales site, which was advertised as the V2. After looking into it, I was probably scammed and sold the V1 in it's place, and I had believed I had the V2 all this time.
Thanks for your patience and detailed replies.