Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: derryckw on June 29, 2020, 12:42:19 pm
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New to the board but not new to building amps, just want to get some opinions insight on how the 5F11 Speed control "should" work. This is my first 5F11 but have built 5G9s and the first thing I notice is the speed control on the 5F11 does nothing until it's half way up, depth seems to work fine but only if I set the bias of the amp below 60% which I'm not to worried about since it jumps up to 70+ while the trem is working. The 5G9 Speed control works from the beginning so did I do something wrong or is this normal for this amp, I've never played one before so no idea. I did find a couple of Videos and they were showing some trem at 4 so I'm guessing something is wrong, it's almost like the 2M is to big and I'm not getting any control until 1M.
Anyway any thoughts, guesses etc would be welcome, all my voltages are spot on to the original fender schematic, took a little doing but they are there!
Thank you
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Have you tried with a logarithmic tapered potentiometer and a linear tapered potentiometer ?
Franco
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I had considered that but don't have any 2M Logs, I may just go ahead and try 1M in both
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3M reverse audio works well with a .022uF cap coming off of the plate.
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Thanks, I'll get some of those and the 2MLs on order, I'm throwing in a 1Meg but my concern is not being able to shut it off completely without a foot switch attached.
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Yep thats exactly what happened with a 1M at 0 I'm already in the Trem
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Help me understand exactly what the symptoms are...
Are you saying you have no tremolo effect until the speed pot is turned half way up?
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Are you saying you always have tremolo effect for all settings of the speed pot, but you just cannot change the speed until the pot is turned half way up?
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with the 2M Linear pot I have no Tremolo until it's half way up, from there it works normally, Depth control works fine once the Trem starts.
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Ok, I'm an idiot!!....was walking through the schematic and realized that V1 is a 12AX7 not a Y7 which I installed out of habit I guess, put the X7 in there and it works perfectly, of course that is the tube that the Trem is using in the 5F11 so it makes a bit of difference! Thanks for the help! details, details, details!