Tube for GT AM62
- Thread starter mrc
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Help Support GroupDIY Audio Forum:
Are you certain it's the tube, and not a resistor, capacitor, or anything else? Check the power supply voltages with the mic connected. If any of the voltages are incorrect, shut the power off immediately and troubleshoot.
I just looked at a NOS NIB 5840 (RCA 9/60 vintage) out of the box and it has 8 leads.
Sounds like the unused leads were clipped in your mic. The 5840 isn't as expensive as a AC701, but with tubes getting rarer and more expensive, don't blame the tube first...You'd think twice about blaming the tube if you were dealing with a AC701 since replacing one of those is serious cash.
I just looked at a NOS NIB 5840 (RCA 9/60 vintage) out of the box and it has 8 leads.
Sounds like the unused leads were clipped in your mic. The 5840 isn't as expensive as a AC701, but with tubes getting rarer and more expensive, don't blame the tube first...You'd think twice about blaming the tube if you were dealing with a AC701 since replacing one of those is serious cash.
okgb
Well-known member
I believe that's a pentode tube [ look it up to be sure ] so clipping the leads if they're using it as a simple triode
seems possible
seems possible
Thanks, guys! I guess I need to update my glasses :
I completely missed the clipped ends. That's great I have 10 nos 5840's here. The idea of checking the circuits is good, too, but I can't seem to google a schematic for it.
Does anyone know where to find the schematic for it? I can't seem to find it in the meta, as well.
I completely missed the clipped ends. That's great I have 10 nos 5840's here. The idea of checking the circuits is good, too, but I can't seem to google a schematic for it.Does anyone know where to find the schematic for it? I can't seem to find it in the meta, as well.
moamps
Well-known member
Thank you so much! Those tubes are rare birds! I've had two, "TWO" mics, in the last month that have needed these replaced. I absolutely love these mics and have been using them for years in my project studio, to record my rather gravelly voice. They capture all the frequencies quite naturally. Wish I could afford something a little more expensive, but I'm perfectly happy with what I've got!
hitchhiker
Well-known member
This schematic came from GT when I was fixing a GT 6TM , which was almost the same mic. My notes
are about that the 6TM so my wire colors are likely different than the AM-62 The pic is with my phone.
The two top left hand resistors missing values are 1 meg.
Just to be clear this schematic is labeled AM-62 rev3
are about that the 6TM so my wire colors are likely different than the AM-62 The pic is with my phone.
The two top left hand resistors missing values are 1 meg.
Just to be clear this schematic is labeled AM-62 rev3
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40 Euro for one tube? Perhaps they are selected/graded/burned in? I have bought a sleeve of five 5840 on ebay for less than that.
moamps
Well-known member
I have no idea how they formed the price in GT and how much better these tubes are (selected for the lowest noise, etc.) compared to the standard EF732/5840, which can be bought at very reasonable prices on eBay.
I looked up the EF732 tube which is the same as a 5840W. The groove tubes is a 5840M which is a 5 pin and has only 5 leads. I noticed that the EF732/5840W has more pins and more leads. Could the EF732/5840W be adapted to fit in place of the 5840M?
user 130681
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The 6N16b pencil double triode is very similar electrically and on the surplus market command around $3 each from Ukraine.
I use them in my microphone pre amps and high end guitar pedals because they work realy well at low voltages. And they look cool on display!
I use them in my microphone pre amps and high end guitar pedals because they work realy well at low voltages. And they look cool on display!
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Re GT 5840M lead count, 145boogie, I suggest reading this complete thread from post #1.
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