Hoffman Amplifiers Tube Amplifier Forum
Other Stuff => Effects => Topic started by: Dive on December 12, 2010, 11:25:18 am
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I have built a plexi 50 so far, and like it, but it has no reverb. I'm wanting to build another amp and add reverb with it. I need to know more about reverb, and the reverb tanks. How they function. Are they always placed in the speaker cabinet to pickup vibration there, and I suppose the springs vibrate and is there some kind of pickups in it that is then fed back up into an amp stage? If so what controls are generally needed, phasing, delay, amplitude, etc..?? Is this fed into a preamp stage or a later stage ??
Thanks for any explainations provided.
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The tank has a series of springs that the signal passes through that causes the reverb. Some units have more springs for longer dalay/deeper reverb. The reverb is created by a sepeate reverb circuit where the a sample of the guitar signal is borrowed from the amps preamp output stage just after the tone stack to the reverb loop where it passed through a driver preamp tube stage/then the reverb transformer/then Reverb tank/then Recovery tube preamp stage/Reverb Pot---then the wet reverberated signal is redirected back the the amp circuit just before the power amp stage. The reverb switch is usually set up to ground the reverb circuit out when turned off. This is very general and I may have something wrong---but is the basics but a lot more finite details are involved when you get into it. Plate
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Go here... http://www.accutronicsreverb.com/
Read: How Reverb Works.
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I have installed many reverbs and in a blackface spring reverbs are great. I had a spring in a plexi. Then I tried a Verbzilla pedal, the rest is history.
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my 2cents...you might want2 entertain the thought of efx in-out + whatever verb (digital or tube driven an alog) for your plexi. reasons being; reverb in amp= noise. lead dress,rev. cables, proximity to other components, etc.. i have a plexi re-issue w/efx loop that is quite nice. i've had modded marshalls(by some of the ''name guys'', and it seems that every added tube=added noise. I just completed my 1st ground up build (non 'kit' parts),and attention should be given at all levels-high quality cable connections, as short as possible, wire+component layout+dress,all of the important stuff seems to be more important in the rev. section. if your amp is stock copy of plexi,(chassis,tube layout,etc.) maybe research into best areas for the addition. if you're building a 'mutt' like i did, then definitely research tranny, tube, total parts placement & shoot for high quality parts. i'm very pleased w/my 18 watt stout reverb, and the tube reverb sounds sweet, but i went w/a small chassis, and found out the hard way(some of the best learned lessons).either way, best regards!.
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It is difficult to beat the tradition fender spring reverb. Having said that, if room is an issue and you want to try reverb with one tube .......... here is a thread from ARCHIVES on doing that.
http://www.el34world.com/Forum/index.php?topic=7957.0 (http://www.el34world.com/Forum/index.php?topic=7957.0)
With respect, Tubenit