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Tube Practice Amp Adding Reverb

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  • Tube Practice Amp Adding Reverb

    I have a 10 watt tube amp and would like to add spring reverb. I have a few reverb tanks the amp has trem which I don't use so could I use this circuit to add the reverb and how would I go about this mod?

  • #2
    We really need to see a schematic to say anything of value. What are the model numbers of the tank you have to hand?
    Experience is something you get, just after you really needed it.

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    • #3
      One is a Belton bsn2eb2e/t out of a Kustom kpa80 pa head the other is a Accutronics it has 121-000159 and qc 233 out of a Hammond Concord organ the amp is a Silvertone mod 257.14211000. Tubes are 12ax7 preamp 7189 power 12ax7 trem and 6x4 rect
      Last edited by Wolfman88; 10-19-2019, 07:31 PM.

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      • #4
        Still need a schemo. Not optional.

        The bsn2eb2e/t is a 2 spring, medium decay, 600 ohm input impedance, 2.25k ohm output impedance. Commonly made to work with an opamp or two.

        The other numbers I don't recognize. Grab a meter and measure the DC resistance of the input and output coils. From that we can compare with published data to figure out what the impedaces of the coils are.
        Experience is something you get, just after you really needed it.

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        • #5
          Measure on the Belton ot the Accutronics? I'll try to find a schematic on the amp.

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          • #6
            Its also known as the 10xl amp this is the schematic http://schematicheaven.net/bargainbi...rtone_1421.pdf its a sears and roebuck amp from the early 60s. I plan on doing some maintenance like recapping and new tubes since it has the original silvertone tubes. I want to replace the trem with reverb.
            Last edited by Wolfman88; 10-19-2019, 10:06 PM.

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            • #7
              Here's a direct copy:
              Attached Files
              "Everything is better with a tube. I have a customer with an all-tube pacemaker. His heartbeat is steady, reassuring and dependable, not like a modern heartbeat. And if it goes wrong he can fix it himself. You can't do that with SMD." - Mick Bailey

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              • #8
                Anyone? Please I'm new to modding amps and need guidance from people that know what their doing on this. As said I would like to replace the trem with the reverb tank so that way the reverb will have its own tube circuit. I'm making this amp as a tube preamp for my main stack which doesn't have reverb and I think it would be easier to add the reverb to the tube amp so I'll have a tube preamp with spring reverb. So please anyone I would really like to do this mod to my amp. The schematics of the amp I posted. Also I don't know what tank to use the long spring or med spring I'm thinking the Belton med spring because I don't use a lot of reverb but maybe the long spring would have a better sound? I have the tube circuit and pots for the trem I can re purpose for the reverb. And I need to know how to convert the speaker output into a line out I remember seeing this can be done but can't remember how to do it because using this as a preamp for my main amp I'll need a line level signal instead of feeding 10 watts into the input of my main amp head.

                So please anyone help I'm begging the people that can help to help me do this.

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                • #9
                  Originally posted by Wolfman88 View Post

                  So please anyone help I'm begging the people that can help to help me do this.
                  We were waiting on you "Grab a meter and measure the DC resistance of the input and output coils." That's all the unknown ones, of course.
                  Experience is something you get, just after you really needed it.

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                  • #10
                    Like I asked before do yaw need the measurements from the Belton or the Accitronics It seems the value of the belton is already known from a previous post so I'm thinking yaw want the Accutronics?

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                    • #11
                      Originally posted by Wolfman88 View Post
                      Like I asked before do yaw need the measurements from the Belton or the Accitronics It seems the value of the belton is already known from a previous post so I'm thinking yaw want the Accutronics?
                      The Accutronics as it's the unknown one. I gave you the info for the Belton in post #4.
                      Experience is something you get, just after you really needed it.

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                      • #12
                        What should setting should I use on the ohm meter 2K?

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                        • #13
                          Strart on the lowest range, if it reads "OL" or something similar, try the next range up. This info would be in the instructions that came with the meter.
                          Experience is something you get, just after you really needed it.

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                          • #14
                            I *oogle-d the Accutronics number provided and it came up associated with an old Gibbs tank. Old enough that it would have been used in a tube circuit. Cap coupled or transformer coupled is still a question, but probably transformer coupled. Just an observation that may help.

                            Other than that... The amp in question has only two preamp tubes. Or, more properly, one preamp triode, one driver triode and two triodes used for a tremolo circuit. If the Accutronics tank is for a transformer circuit then to get decent reverb performance I think we need one more stage. Or not, depending on how much we can bump the dry signal with circuit changes to recover what will be lost by balancing it with the wet signal. Looking at the schematic there are some opportunities to do this. Adding a transistor stage may or may not be in the picture considering that it would require the addition of a low voltage supply.

                            That said, I think it may be best to scrap the proposed, available reverb tanks in favor of buying a new one. They're not prohibitively expensive, it's a known quantity at that point and most old tanks have some are related problems due to hardening of the plastic/rubber products used in their manufacture. This is a combo amp so microphonics may be an issue.

                            I'll upload the schematic and modify it for what "I" might do. Trying to keep it as simple as possible.
                            "Take two placebos, works twice as well." Enzo

                            "Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas

                            "Being born on third base and thinking that you must have hit a triple is pure delusion!" Steve A

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                            • #15
                              Ok. It's a little clunky, but I think this should work

                              Attached Files
                              Last edited by Chuck H; 10-21-2019, 05:38 PM.
                              "Take two placebos, works twice as well." Enzo

                              "Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas

                              "Being born on third base and thinking that you must have hit a triple is pure delusion!" Steve A

                              Comment

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