Questions about Revibe circuit

[Keppy]

Hey everyone! I'm thinking about building a Revibe, but the schematic has me scratching my head a bit regarding some of the choices made. I was hoping someone with more experience could tell me if I'm missing something.


https://el34world.com/Hoffman/files/Hoffman_ReVibe.pdf

• Why is the output impedance so high? Every signal path goes through several hundred kΩ of resistance between the last tube and the output. It seems like this would cause treble loss when combined with cable capacitance on the output, which, sure enough, is a complaint that I've seen. I realize this is largely due to copying the 6G15 reverb circuit, but...
• Why are there two input stages? It seems to me like a single input stage could drive both the reverb and trem, leaving a triode available to use as a cathode follower to buffer the output.

What do you think? Is this worth trying?

[sluckey]

1. The two 220Ks are mixing resistors. They also prevent the mix pot from affecting the vib signal. The 330K/10K voltage divider on the vib output is necessary to knock the signal level down to an instrument signal level.

A single stage could drive the reverb and vibrato circuits as you say. Perhaps using V1B as a CF would be a good idea. However, IMO the Revibe works very well as is.

I made several changes to my Revibe but nothing that would address your concerns.

[Keppy]

Thanks for the response! I've definitely consulted your Revibe documentation while thinking about this. I'll report back if I ever get around to trying this out.