Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: WonderAliceLand on December 17, 2018, 01:57:55 pm
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I found a Gibbs 1122 reverb tank on ebay for $20 so I picked it up (this GAS is killing me, please :help:). Thing is, it doesn't have any distinguishing markings besides a copyright plaque and "1122" stamped into the metal.
I know Ohm readings are important, so the ohm input is 179.3Ohms and the output is 176.9Ohms.
I would love to know the type or at least HOW she is supposed to mount it. Here are a few pics, if you need any more, go ahead and ask, but there isn't much info on this thing.
Thanks for your help in advance! This is my first post on the forum, I look forward to talking with you all, have a pleasant day!
-Alice
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You must truly love
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what amp is it for
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It's the equivalent of a 4FBxxxx for direct drive reverbs. Won't work for transformer driven reverbs.
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what amp is it for
I don't know what it came out of or what it was made for. She has an G-Storm Electro "Spring Tank Reverb" module. And yes, I do truly love her ^.^ Both of us are weirdos and don't fit in with many people besides eachother, super geeky and music nerds; we met playing videogames and she moved across the state to live with me two years ago, so this is a holiday/anniversary present.
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It's the equivalent of a 4FBxxxx for direct drive reverbs. Won't work for transformer driven reverbs.
Thank you! Do you know on the off-chance if it will work with the G-Storm Electro "Spring Tank Reverb" module?
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You already bought it, you are stuck with it.
There's nearly no info on this "module", unless you know more than we do. The supply specs do suggest op-amps.
The 170r coils suggest 600-1K audio impedance which is often a good fit for opamps.
So "definite maybe". Santa's Elf could sneak into her synth-chamber and try it ahead of time, in case it is a dud and Santa needs a Plan B.
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You already bought it, you are stuck with it.
There's nearly no info on this "module", unless you know more than we do. The supply specs do suggest op-amps.
The 170r coils suggest 600-1K audio impedance which is often a good fit for opamps.
So "definite maybe". Santa's Elf could sneak into her synth-chamber and try it ahead of time, in case it is a dud and Santa needs a Plan B.
Glad to hear, I'll try to test it out, just don't want to break anything.
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I once bought an ice-cream scooper for my wife as a present. That was 40 years ago! I suspect you will remember this gift for the rest of your life too! Sorry.
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Oh, mounting. Screw through the side flange holes into a cabinet. If footsteps make the springs sound, use washers or grommets so it floats on rubber. Inside a speaker cabinet we sometimes use a padded vinyl "sleeping bag" around the tank. On BIG stages, Neil Young drills a hole, puts the tank under the stage on concrete and runs wires up. But mostly you just screw it to a board.
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Resistance readings mean almost nothing at all with reverb tanks, and transformers. The ohms refers to AC impedance and what gets reflected back from the output to the input, and it is frequency dependent. The only thing a DC resistance tells us is that the coils in the transducers are not shorted or open. Most of what remains on eBay now are all designed for organs, usually solid state organs. Most of those will be medium or short decay too. Test frequencies are 400Hz or 1KHz.
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Resistance readings mean almost nothing at all with reverb tanks, and transformers. The ohms refers to AC impedance ... The only thing a DC resistance tells us is ...
You're not entirely wrong.
But we know DCR is some percentage of actual Impedance, which PRR uses to generate an estimate:
The 170r coils suggest 600-1K audio impedance ...
And then 2deaf uses to figure out the corresponding Accutronics part number:
It's the equivalent of a 4FBxxxx for direct drive reverbs. Won't work for transformer driven reverbs.
When we go to Belton's website, they provide a PDF with the DC Resistance of input and output coils (http://www.belton.co.kr/inc/downfile.php?seq=4&file=pdf), along with the corresponding AC Impedance. This in turns confirms PRR's and 2deaf's estimates.
There's nearly no info on this "module", unless you know more than we do. The supply specs do suggest op-amps.
5 years later, it was a home-run or a strike-out. But those specific brackets were used to vertical-mount tanks in Hammond organs. I don't know which model got this specific tank, but I suspect it was used to siphon a small % of a many-watts speaker-output to directly drive the tank, then applied the tank's output to another amplifier to drive a dedicated reverb-speaker.
Guitarists frequently find this particular model available for little money, and get hopeful it will work in their amp. Then they find it has "weak reverb" because the higher impedance input isn't being driven a such a large signal as found in the original application.
Not that I've fallen victim to this exact scenario... you know... just sayin'.
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Not that I've fallen victim to this exact scenario... you know... just sayin'.
:laugh: