What tubes go in a Twin Reverb?
The circuit used is commonly known as the AB763 circuit. Fender Twin Reverb amplifiers use four output tubes, of the 6L6GC type. They use six preamp tubes, consisting of four 7025/12AX7 types and two 12AT7 types.
Do you need to bias matched power tubes?
Conclusion: You’ll need to bias most tube amps if you change the tubes. This is because you cannot buy tubes with a similarly matched resistance. You should always buy a matched pair or a matched quad of tubes, but the chances of them matching your current pair are very small.
Which tube is for reverb?
Fender Amp Preamp Tube Layout and recommendations
| Fender 2 channel reverb amp preamp tube layout (as seen from the back of the amp) | ||
|---|---|---|
| Tube Designation | V6 | V1 |
| 12AT7 | 7025/12AX7A | |
| Specified Function | Phase Inverter | First gain stage for channel 1 |
Can I use 12AX7 instead of ECC83?
The 12AX7 Valve (or 12AX7 vacuum Tube) is a small preamplifier valve which is identical to the ECC83 – same valve, just a different name. It has two identical triodes both of which have a high voltage gain. It is used in 99% of all guitar amplifiers.
How does the output tube matching control work?
Hence the output-tube-matching control, which alters the bias voltage on one side of the output stage relative to the other. This matches the total current flow of one half of the output transformer primary relative to the other half, eliminating hum.
Are there any alternatives to the 4-lug output tube-balance pot?
Because the original four-lug output-tube-balance pot is no longer available, we need to find an alternative way to balance the output tubes. Balanced tubes in the output stage are a great idea, and I believe Fender engineers added this feature because tubes were still being made on old machinery.
What year did Fender make the 135 watt Twin Reverb?
The 135-watt version of the Twin Reverb that Fender manufactured from 1977 through ’82 differed from previous 100-watt silverfaces. A modded monster regains its former “glory.” I’m hoping you can help me. I recently bought a ’79 Fender Twin 135.
Do I need a bias control on my tube amp?
We really don’t need this function nowadays because matched output tube sets are readily available. I feel it’s better to install matched output tubes and turn this control into a true bias control, but since you seek the original function, I have a fix for you.