2009-11-01 2:25 pm
hi to all
i want to add a reverbtank in a home made guitar amp
i have a spair se 2.5k to 8 ohm and 600 ohm transformer
also a pp 10K to 2.5 _ 4 ohm
can someone advice a schematic to use one off these transformers
or even shematics without transformers to add a reverb tank
i have some el84 , ef86 , and ecc 8XX tubes laying around
thanks in advance


2008-12-18 2:29 am
Use an ECC81 with the two plates in parallel. 5-6 mA for each unit DC current (data sheet operative points are a good start). 10K is fine for this. The secondary of the transformer has to match the impedance of the tank.
Then you need another preamp that could be half of ECC83 or a op-amp.
Actually an op-amp used as a current amplifier will work fine. In fact the spring is basically a coil with its own inductance and the higher the frequency the higher current to drive it. What you don't want is reverb at low frequencies but this is easier to manage, both with the transformer and the coupling caps.