Recently build a tube reverb based on a Guyatone Fr3000 schematic I found in the www. Driving the reverb tank is pretty similar to the Fender Reverb. The second half of the ECC83 is used as a buffer (cathode follower) at the of the chain. Additionally there are 3 JFET for dry signal, mix and volume. The bass knob is basically the 250p cap after the tone control known from the Fender Reverb schematic bypassed by a 1Meg pot.
It works fine with a 2 spring tank. I also tried a 3 spring tank but that was too much.
I observed some distortion after the 6K6 with the scope but was not able to find the cause. Not clipping but the sine wave is deformed. Tried also a different 6K6 as well as a 6V6 with same result. Not sure if this is normal for this kind of schematic. Maybe somebody else had similar observation.
Reverb Build
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Reverb Build
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Stevem
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Re: Reverb Build
What does the output wave form look like?
Is it reaching saturation before cut off, or the other way around?
How far into class A is the output tube biased?
Is it reaching saturation before cut off, or the other way around?
How far into class A is the output tube biased?
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Reverb Build
The tube is biased with a 1k resistor and a 22uF bypass cap. Additionally I added the 56V Zener protection as shown in the Fender Reverb Service Manual.
Unfortunately I took no image of the wave form from the scope. The sine wave was not flattened on the top or bottom.
However, I plan to build a standard Fender Reverb anyway and will see if there is a similar effect.
Unfortunately I took no image of the wave form from the scope. The sine wave was not flattened on the top or bottom.
However, I plan to build a standard Fender Reverb anyway and will see if there is a similar effect.
Re: Reverb Build
Too much guessing on this thread, missing all info
-schematic
-voltages
-oscillograms
Then reverb type, reverb transformer compatibility, drive signals-
zillion things.
In text mode is not possible to repair anything.
From the practice: there is no difference in functionality between reverb 2 strings and 3 strings.
Then concentrated obeserver will ask himself.. how reverb tank in 2 or 3 strings is the same? One working other distorting.Impossible. Interesting. Means what? We are arriving to the solution in very guessing thread.
-schematic
-voltages
-oscillograms
Then reverb type, reverb transformer compatibility, drive signals-
zillion things.
In text mode is not possible to repair anything.
From the practice: there is no difference in functionality between reverb 2 strings and 3 strings.
Then concentrated obeserver will ask himself.. how reverb tank in 2 or 3 strings is the same? One working other distorting.Impossible. Interesting. Means what? We are arriving to the solution in very guessing thread.