trinityamps.com

Hey guys

Not sure how to title the thread . Our Lightnings are extremely similar to the AC30's from the Jennings era in the 60s', and as some of you may remember, I changed some of the components to mirror the Vox values. Last night I was looking at the Hoffman layout for an AC30 purely out of interest and had a question about the way V1 was wired.

Our Lightnings use one 1.5k and a 22ish cathode bias and bypass for all of V1, linking the tube pins. The Hoffman layout uses a separate bias and bypass for V1a and V1b. V1b doesn't have the bypass cap. A similar scheme is used on the 220k plates. Other than the bypass cap detail, is using a separate 1.5k for each side the same as using one and linking the pins? I thought it was interesting. A learning opportunity

In the 15, with all the jumpers across the tube pins, the two triodes in V1 are in parallel.
When comparing the gain of a single triode vs. the gain of two parallel triodes using the same values (no resisotrs changed) the gain of two parallel triodes will be only 3 dB higher than the single triode. The trade off is frequency response so you may need to compensate a bit hence the cathode cap can. At 25uF, the -3dB point is at about 15Hz,

This configuration can have stronger mids, bass, sustain and drive, like jumping channels.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Oh, ok. So rather than being two ways of skinning the same cat, this is basically the same thing as jumping channels. Cool.

The only other difference is the volume pot. We have 1M in the Lightnings and the Vox has 500K. Mine still has the 1M. I may throw the 500K in just to see what it's like.

I love this amp. So much fun to play with.