Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Dyerseve726 on March 09, 2022, 01:43:01 pm
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Hey everyone. Long time lurker, first time poster.
I'm getting ready to order parts for an AA764 Vibro Champ build. The person it is for has asked me to add reverb. I'm thinking the easiest way to do this is with a solid state driven unit as shown on the Rob Robinette site. Trying to stay within a budget, so a bigger chassis and more tubes are out of the question.
My only question is where do I insert the footswitch? If this works the same as in an AA1164, my guess is I'd wire it in just before the wet signal hits the recovery phase. I've marked where I think it should go in the picture in green, next to the 10k resistor. I guess this circuit is from a Hot Rod Deluxe, but I don't see the footswitch in the schematic or the diagram. I assume it has one?
Also, is there any reason this shouldn't work in a Vibro Champ? This is my 6th amp build, but the first time adding reverb to a circuit that wasn't already designed for it. Still fumbling through the process of how it all works.
Thanks!
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A schematic would be much easier to analyze.
Not sure if this is an option for you, but, since you mentioned "easiest"
I think the easiest way would be to drop in a Belton reverb brick
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A schematic would be much easier to analyze.
Not sure if this is an option for you, but, since you mentioned "easiest"
I think the easiest way would be to drop in a Belton reverb brick
Sure, no problem. I've again marked where I assume a good footswitch location would be. Makes the most sense to my mostly untrained eye, lol.
As for using a Belton unit, I just wasn't sure what the sound was like on those. Never heard one. I'm open to ideas though. I'll look into it. Thank you.
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Your results will vary based on your insertion point, but here's an example of one in action.
Belton BTDR-1H-L added to VHT Special 6 Ultra - YouTube (https://www.youtube.com/watch?v=XAYCA3W_KCI&ab_channel=Bobsbluesmusic)
I'm not trying to steer you one way or the other, just food for thought
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I built the BYOC "Spring Reverb" pedal. It uses the Belton brick. It sounds just like reverb to me. :icon_biggrin: The difference would be that I use it in front of my amps, so I really don't know how it sounds inserted within the preamp.
Here's someone's video:
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I built the BYOC "Spring Reverb" pedal. It uses the Belton brick. It sounds just like reverb to me. :icon_biggrin: The difference would be that I use it in front of my amps, so I really don't know how it sounds inserted within the preamp.
Here's someone's video:
Dang, that does sound pretty good. I love BYOC. I have a Green Pony. I'll have to ask the guy how he feels about it. Not sure how much of a vintage snob he is, haha. Thanks for the clip, that really helped.
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As far as your footswitch insertion point goes, we need to know what type of switch you intend to use.
If you used a 1/4" jack to open that connection (green mark) then the wire to the footswitch will be an antenna.
If you're going to use a relay, then there are plenty of options on where to open or bypass the circuit.
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As far as your footswitch insertion point goes, we need to know what type of switch you intend to use.
If you used a 1/4" jack to open that connection (green mark) then the wire to the footswitch will be an antenna.
If you're going to use a relay, then there are plenty of options on where to open or bypass the circuit.
Quarter inch or RCA. Maybe I misunderstand how the footswitch normally works. I thought that when the switch was closed it sent the reverb tank output to ground. Why is it an antenna when placed before an op-amp and not an antenna when placed before a tube? Sorry for my ignorance.
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Quarter inch or RCA. Maybe I misunderstand how the footswitch normally works. I thought that when the switch was closed it sent the reverb tank output to ground. Why is it an antenna when placed before an op-amp and not an antenna when placed before a tube? Sorry for my ignorance.
It's an antenna for both cases. You are running a very weak audio signal out to the footswitch. Maybe even 15 feet or so. Shielded cable is a must.
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Quarter inch or RCA. Maybe I misunderstand how the footswitch normally works. I thought that when the switch was closed it sent the reverb tank output to ground. Why is it an antenna when placed before an op-amp and not an antenna when placed before a tube? Sorry for my ignorance.
It's an antenna for both cases. You are running a very weak audio signal out to the footswitch. Maybe even 15 feet or so. Shielded cable is a must.
Gotcha. I usually wire up RCA jacks on the footswitch itself so any cables can be used. I haven't had any issues with noisy reverb. However, if there is a more logical place to put one in this circuit, obviously that would be best.
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I guess this circuit is from a Hot Rod Deluxe, but I don't see the footswitch in the schematic or the diagram. I assume it has one?
Just for the record - I checked the schematic and asked Google and it appears the HRD does not have switchable reverb.
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I would connect the switch to the wiper of the reverb pot.
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I guess this circuit is from a Hot Rod Deluxe, but I don't see the footswitch in the schematic or the diagram. I assume it has one?
Just for the record - I checked the schematic and asked Google and it appears the HRD does not have switchable reverb.
Good to know! My bad. I should have Googled that. Seems odd to see a Fender amp without a switch for the reverb.
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Seems odd to see a Fender amp without a switch for the reverb.
Yeah, surprised me too.
Although, when I play through my DR I never turn the reverb off, so that may be a question you want to ask your friend.
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Yeah, surprised me too.
Although, when I play through my DR I never turn the reverb off, so that may be a question you want to ask your friend.
Same. I don't even connect the switches on my PR clone. Reverb and Trem on all the time.