But be careful while changing tubes and switch off the amp each time you chance them and only catch the tube and no other components inside the amp. Set each tube to a different position, one after another and you will hear while playing if it is better or worse. Try to get selected low noise tubes, it´s always worth the money.Īfter you got some tubes, take your time to experiment.
Good ones we can suggest are TAD Premium, Tung Sol, Valvo (NOS), Telefunken (NOS), Genalex Lion, Mullard, Silvania. Than you need at least 5 different tubes as basic for experimenting. Let´s say we got 3 tubes for the channels including the phase inverter tube.
If you´re not shure have a look in the manual or at our Info Page. Top Boost and Normal Channel mostly use ECC83/12AX7 tubes. The number of preamp tubes in the AC30 varies between the models. If you want to use other types of tubes be sure they match the specifications and the socket-layout. To really improve your sound, it is necessary to buy different factory tubes, more than you will need in the end. Good news, preamp tubes (exept NOS (New Old Stock) tubes) are in general cheaper and have more impact to the sound. Those tubes mentioned above, especially matched quartetts of EL84, tend to be expensive so you maybe don´t want to buy more sets than needed. In our experience, the difference can be more than 50V between different factories.
The main way they affect the sound is by the different output voltage they deliver to the amp. The rectifier, the GZ34 in AC30s delivers the DC the power tubes use. That´s the main difference when we tried different factories (those were TAD, Mullard (new), JJ and EH). Different power tubes, the EL84 in the AC30s, can make the sound thinner or more full. But also the power tubes and rectifier tube (if you have one) have an influence. Usually, the most significant improvements in tone can be achieved by changing the preamp tubes. You may follow other peoples experiences and best practices, but if you want to find the right tubes for your taste, you should consider a decent amount of time to try and experience for yourself.ĭifferent tubes may not only change the tone, but also the amount of gain/distortion respecitvely the amount of headroom. Moreover, there are a lot of tubes available and the possible combinations are barely limited. Even different AC30 models may react differently to different tubes. However, it might not be an easy task to find the right tubes for your amp and your personal needs. In many cases, factory tubes are not the best sounding ones available and the tone can be significantly improved by upgrading to better tubes. Most amps can be improved by changing tubes. Depending on the actual model, accessing the tubes may or may not require removing the amp chassis.You should always get a matched set of power tubes.This means, you do not have to rebias your amp after you’ve exchanged tubes – just exchange them and you’re done. The AC30 is a cathode based amp with auto-bias.Are you saying that the black and the red wires should come off of pin 2 and pin 8, respectively? This one has the red wire-which I take to be the B+.coming off of pin 2 and the black is one pin 8.This article provides some information about tubes in conjunction with the AC30 amplifier. Have you checked that externally accessible 1/2 amp fuse? That would be safer than pullng them to check them. IF you have a multimeter/ohmmeter, you can check for continuity across those fuses without removing them. I don't know if these have a cap drain circuit in them or not. DAnger exists even with the amp unplugged fi there is voltage. Pull that rectifier while being careful to take note of the pin location relative to the socket so that you can ascertain whether or not you misoriented that tube in that socket.Īs for which fuse? One might be curious to know your experience before suggesting that you start pulling fuses out of those two positions on the board.right next to some filter caps.
IF that happened, cross your fingers that a fuse saved your PT. I learned soem years ago that JJ's will go into a lot of sockets in any alignment. +1 with Phil_tre on the possibility of installling that JJ rectiifer incorrectly, izakly.