Hi all,
So, I've built this 5f2-a clone from scratch, it works now but it sounds incredibly bad compared to recordings you can find on the web of this amp.
It sound really muddy and dull and has lots of low mids and bass plus when I turn up the volume it gets even worse and it stays pretty clean too, even at high volumes..
I already tried lowering the coupling caps to 0.01, wich hasnt helped.
Does anybody know what could be wrong with my amp?
I attached a picture of my built (not in a chassis yet) and the voltages I measured on it.
Thanks and wxcuse my english again, i'm german..
Mo
So, I've built this 5f2-a clone from scratch, it works now but it sounds incredibly bad compared to recordings you can find on the web of this amp.
It sound really muddy and dull and has lots of low mids and bass plus when I turn up the volume it gets even worse and it stays pretty clean too, even at high volumes..
I already tried lowering the coupling caps to 0.01, wich hasnt helped.
Does anybody know what could be wrong with my amp?
I attached a picture of my built (not in a chassis yet) and the voltages I measured on it.
Thanks and wxcuse my english again, i'm german..
Mo
Attachments
Double-checking the wiring is always my first troubleshooting step - I've made some pretty basic mistakes on projects!
Are all your ground connections correct? (It's easy to miss something when there's no chassis.)
One possibility is that you have some oscillation happening (above hearing range) - that can affect the sound you hear. I've had that problem with 'breadboard' style amps (too much wire!) before.
You really need a scope to see oscillation problems, I think.
Are all your ground connections correct? (It's easy to miss something when there's no chassis.)
One possibility is that you have some oscillation happening (above hearing range) - that can affect the sound you hear. I've had that problem with 'breadboard' style amps (too much wire!) before.
You really need a scope to see oscillation problems, I think.
Check the cap values around the tone control. The schematic I am looking at says one at .0005uF (= 0.5nF = 500pF) and the other at .005uF (= 5nF).
Welcome to the forum!
The first thing is to say it's best to keep all problems/questions from the same amp in one thread. I see you posted earlier about a high frequency oscillation problem. Part of the solution was reversing the OT leads so you had Neg FB rather than Pos. FB. Later you said moving things around made a different noise go away. If the others who are answering your question in this post knew that, they would have said most likely you have a radio frequency or other interference problem. Victoria Guy hinted at that but would have said most likely it's the problem if he knew that information.
One thing you can do is to twist all the wires from the input jack to the amp and the wires to and from the volume and tone pots together like your heater wires and make them shorter. They are acting like antennas right now picking up high frequency interference. The amp is probably amplifying those signals above hearing range and drowning out the guitar's signal. It's this or you had a loose connection and moving things made the connection better.
Another thing you can do is to post a schematic like you had in your first post, that has all the voltages at the socket pins, not just at the power supply. Also include the bias voltages on pins 3 and 8 on the 12AX7 and pin 8 on the 6V6. Also, the plate voltages for all tubes and the screen voltage for the 6V6.
And yes, check your wiring again, making sure you didn't miss anything. Many times this usually will show up as a wrong voltage somewhere if you can't find a missed connection.
The first thing is to say it's best to keep all problems/questions from the same amp in one thread. I see you posted earlier about a high frequency oscillation problem. Part of the solution was reversing the OT leads so you had Neg FB rather than Pos. FB. Later you said moving things around made a different noise go away. If the others who are answering your question in this post knew that, they would have said most likely you have a radio frequency or other interference problem. Victoria Guy hinted at that but would have said most likely it's the problem if he knew that information.
One thing you can do is to twist all the wires from the input jack to the amp and the wires to and from the volume and tone pots together like your heater wires and make them shorter. They are acting like antennas right now picking up high frequency interference. The amp is probably amplifying those signals above hearing range and drowning out the guitar's signal. It's this or you had a loose connection and moving things made the connection better.
Another thing you can do is to post a schematic like you had in your first post, that has all the voltages at the socket pins, not just at the power supply. Also include the bias voltages on pins 3 and 8 on the 12AX7 and pin 8 on the 6V6. Also, the plate voltages for all tubes and the screen voltage for the 6V6.
And yes, check your wiring again, making sure you didn't miss anything. Many times this usually will show up as a wrong voltage somewhere if you can't find a missed connection.
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