sonolink
Well-known member
Hi,
I recently finished an old project consisting of a tube preamp (AB763) inside a pedal, followed by Merlin's CabSim followed by a D.I. output based on an Elliott Sound circuit. The pedal has a instrument input, a mono output to connect it before an amp OR before a power amp (like in the FX loop return), and a TRS balanced output.
I first began building the unit only with the PSU components to check the voltages were right. Everything was fine (B+=190VDC, Heaters=6VDC).
I then added the AB763 components, input and jack output and tried it on an amp with a guitar. After some adjustments made following forum member Matador advice, it sounds great both before the amp or in the FX loop return.
I then added the DI output section and noticed that the sound was ok when using a LINE input in my MOTU soundcard (guitar -> pedal -> DI out -> souncard TRS in), but noisy when using a preamp input. Also, I noticed that after a few minutes of playing there was a loss in volume. If I unpower the pedal and power it back up the volume comes back and fades away after a couple of minutes...
I finally added the rest of the circuit (Merlin's CabSim) just in case this had to do with components missing on the board but the same thing happens.
Could this be some capacitor? Any ideas/suggestions please?
This is the schematic of the whole circuit:
Thanks a lot for your time and help
Cheers
Sono
I recently finished an old project consisting of a tube preamp (AB763) inside a pedal, followed by Merlin's CabSim followed by a D.I. output based on an Elliott Sound circuit. The pedal has a instrument input, a mono output to connect it before an amp OR before a power amp (like in the FX loop return), and a TRS balanced output.
I first began building the unit only with the PSU components to check the voltages were right. Everything was fine (B+=190VDC, Heaters=6VDC).
I then added the AB763 components, input and jack output and tried it on an amp with a guitar. After some adjustments made following forum member Matador advice, it sounds great both before the amp or in the FX loop return.
I then added the DI output section and noticed that the sound was ok when using a LINE input in my MOTU soundcard (guitar -> pedal -> DI out -> souncard TRS in), but noisy when using a preamp input. Also, I noticed that after a few minutes of playing there was a loss in volume. If I unpower the pedal and power it back up the volume comes back and fades away after a couple of minutes...
I finally added the rest of the circuit (Merlin's CabSim) just in case this had to do with components missing on the board but the same thing happens.
Could this be some capacitor? Any ideas/suggestions please?
This is the schematic of the whole circuit:
Thanks a lot for your time and help
Cheers
Sono