Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: TIMBO on May 22, 2013, 04:12:13 am
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Hi guys, Got a tank from an old electric organ and can't fine any specs on it.
The input reads 31.9 ohms and output is 183.2 ohms, if this helps at all. Thanks
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Some time ago I posted here in the forum a link where they say that using the resistance will approximate the impedance of the unit
http://www.el34world.com/Forum/index.php?topic=14318.0 (http://www.el34world.com/Forum/index.php?topic=14318.0)
I think that if you use the transformer approach (not the direct drive of the tank without transformer) you can use the unit
have you an amp with a reverb circuit as to give it a try ?
Ah, I forgot to say, seems that the arrangement of the 3 springs is in series instead of in parallel, so I suppose a long delay from that tank
K
p.s.: I think that also Roly at www.guitargear.net.au (http://www.guitargear.net.au) can give you some info about
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It's a 300:2K, suitable for op-amp drive and recovery.
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I like the label, "Manufactured by beautiful girls in Milton, WI under controlled atmosphere conditions".
LOL.
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This IS the Hammond reverb. For a time they were built under another name, but all the same designs and probably same production machinery.
Yes, the "beautiful girls" runs have more mojo. But you use them just like any other vintage USA tank.
The audio impedance is *roughly* 10 times the DC resistance. The key parameter is the 30 ohm DC (~~300 Audio) input. This is a poor match to the usual Fender reverb transformers (4-10 ohm). This is a poor match to the transformerless triode (~~1K-2K) as used by Ampeg and others. It's great if you have 150/600 ohm studio line driver. It is often used with opamp drivers.
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Thanks guys, Would it be possible or worth it to build a stand alone SS reverb to plug in up front or in the FX loop.
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Would it be possible or worth it to build a stand alone SS reverb to plug in up front or in the FX loop.
Have tank, will build? :-)
new tanks aren't too expensive, the MOD hammond-style tanks list for $20 or so.
If you want a reverb unit, decide on the circuit you want to build, and then get correct tank. If you decide on an SS circuit, maybe you save $20 using the tank you have....
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Thanks guys, Would it be possible or worth it to build a stand alone SS reverb to plug in up front or in the FX loop.
yes.
a friend and i were playing on a blues deluxe i had in for repair. it's a decent sounding amp. we concurred that the reverb was decent. copy the reverb ckt. below. one dual OP-AMP should do it. add another if you want to mix dry signal.
http://www.el34world.com/charts/Schematics/files/fender/blues_deluxe_2.pdf (http://www.el34world.com/charts/Schematics/files/fender/blues_deluxe_2.pdf)
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Thanks guys, Something to ponder over. Terminalgs, I always try to put reverbs in my builds but they become expensive here. A tank can cost $40 and a 12AX7, $20 and I always have an FX loop in my builds, so to have a stand alone FX would be good. Thanks
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Hi guys', Just found this http://www.generalguitargadgets.com/index.php?option=com_content&task=view&id=43&Itemid=26 (http://www.generalguitargadgets.com/index.php?option=com_content&task=view&id=43&Itemid=26) and looks like a good fit. Thanks
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A lot of people have had a lot of trouble getting the Stage Center plan to work well. The topology could be different and the gain staging seems very odd.