grid leak bias on preamp stage

[panhead]

I'm building a "bigger" version of the Gretsch 6150 amp for a customer. I'm trying to keep it pretty much the same, but with an EL34 or 6CA7 and the iron to handle it. The amp is extremely simple. It has grid leak biasing on the first preamp stage: a .005 cap in series with the grid, a 6.8 meg resistor from grid to ground, and a grounded cathode for half a 12AX7. Never built a grid leak bias stage before, so I'm wondering what to expect.

[phsyconoodler]

Why not just make a cathode biased stage?Simpler and it will likely sound better.The grid leak bias method is kind of a throw back to the days of octal preamp tubes. just my .02

[PRR]

> I'm wondering what to expect.

Earlier overload. Such stages fell out of favor with mid-late 1950s hotter pickups.

It may be what customer WANTS.

Build it stock, but leave places to re-build it "normal". Know where you can put a cathode R-C network, how to jumper the input cap, and put 1Meg-1.5Meg in-parallel-with/ instead-of the 6.8Meg.

[panhead]

Thanks,

It's such a simple circuit that I'll be able to leave room on the tagboard for the additional components if it doesn't work out well with the grid leak bias.

[Fresh_Start]

Here's an off the wall alternative if you don't like the sound of the grid leak bias - battery bias.  I've been thinking about trying it for a while just to find out what it sounds like.  A 1.5 volt battery is easy to find and the current draw is so small it ought to last for quite a while.

Probably a goofy thought, but I already typed it out...

Chip