It acts both as a source of distortion and as an impedance buffer that protects the gain in the gain stage from the frequency-dependent load of the tonestack following it. Basically, the AC30 isn't wasting a tube by using a DC coupled cathode follower. The article Martin linked to elaborates on this far better than I could. Since a cathode follower has such a high input impedance, it has very little effect on a gain stage, while its low output impedance means it can drive loads of low impedance.Ī DC coupled cathode follower, on the other hand, creates a distortion of its own by compressing the positive peaks of a preceding gain stage. So if you connect a circuit with a low input impedance to a gain stage, you are placing a small resistance in parallel with its plate load - which reduces its gain. As the load resistance decreases, so does the gain. Using either small signal models or load lines on tube transfer curves for a tube arranged as a gain stage, the gain depends on the load resistance. AC coupled cathode followers (hopefully) serve as a "transparent" impedance buffer in the circuit - that is, they have a high input impedance and a low output impedance due to their 100% negative feedback (which is the same reason their gain is slightly less than 1). I'd like to add to Martin's post that that cathode followers can be AC coupled or DC coupled to the previous gain stage. In particular, I hope that this explanation based on these circuits. I want to know about the role of cathode follower in detail. I likes the clear and straight tone character of it.)
![cathode follower cathode follower](https://i.imgur.com/kpamIlu.png)
I don't want to waste a tube if there's no particular benefit.īut if it has attractive benefit, It will be better to make Vox. What is the benefit with add a cathode follower on Rockerverb clean channel? They are almost same circuit except the cathode follower.
#CATHODE FOLLOWER PORTABLE#
I like the clean channel of Orange Rockerverb very much, so I considered to make a portable one-channeled clean amp.īy the way, when I look at the circuit, I found the Rockerverb clean channel is very similar with Vox Top-boost circuit with no cathode follower. The reason that I wonder about it is I agonize circuits for make a diy amp. So then, why they waste a half of tube with add a non-amplified stage? It's only things that I know about itīut many guitar amp circuit has no cathode follower and has no problem. Can someone explain to me how and why the cathode follower circuit works I have run across it in some early 50s HI Fi books and it just looks backwards. It dosen't amplify, only lower the impedence. Mounting with Threaded Grommet.I want to know the exact function of cathode follower. Suitable for the Drip OPTO 4 and OPTO 5 (LA-2A) PCB.įEATURES Combination core using Mumetal 30% and high grade M6 Grain Oriented Silicon Iron (70%) for high level capability whilst ensuring minimal distortion particularly at mid and high frequencies. It is similar to the board shown above except the low voltage signals are routed through a ribbon cable.
#CATHODE FOLLOWER PC#
Cathode follower has a voltage gain of slightly less than 1, a low output resistance of. The cathode follower amp is the PC board on the right. Introduced to provide a mumetal can option at reduced cost transformer option relative to our type 1010. Lets design a load line of a cathode follower based on 6922 tube.
![cathode follower cathode follower](https://tubecad.com/2016/02/05/White%20Cathode%20Follower%20Power%20Buffer.png)
Similar to UTC A24 and Triad HS-50 (in overall 5:1 configuration) but with improved bandwidth. Sowter 1290 Sowter Type 1290 AC coupled cathode follower Output Transformerįor use in a high performance valve compressor/amplifier etc for driving a balanced line from an ac coupled cathode follower or SRPP circuit.