Tube matching and biasing

[R.G.]

Yes, there is. But I was making somewhat of a rhetorical comment for the sake of giving you feedback, because I'll probably work out my own solution to the problem by the time you get around to bringing a kit to the market. I do think that a kit like the one you proposed would have some value.

Oh, yeah, I know. The realities being what they are, a product would take some time to get to market anyway.

If you want some suggestions on how to package an independent bias setup for this, PM me.

If one were available today, at the right price, that would fit into this project, then I'd be all over it. I think that other people might be interested in an off-the-shelf solution. For them to sell well, it would have to be compact enough to fit unobtrusively into the "average" amp.

Actually, I think I have that.

One potential problem in marketing such a kit is that your target market is comprised of people who understand the biasing problem well enough to be willing to seek-out and pay for a canned solution. There's the risk that people who understand the problem well enough to seek out a solution might also be inclined to roll their own solution. There's a risk that you'll be aiming at sort of a self-cannibalizing market, so to sell the solution it would have to be cheap. Unfortunately, cheap tends to put a limit on your ROI.

Yep. Fortunately, the "investment" has already been spent. There's not a lot here that can't just be ordered up and done.

In this application real-estate is a real problem. No space on the back panel, no space inside of the chassis, no space on the underside of the chassis at the back:

Wow - you're right, that's pretty tight. I have a couple of ideas that might work OK, though. What I have in mind might well fit on top of the doghouse. It's pretty compact.

I don't really like the fixed bias circuit as it exists in this amp. It has an adjustment for push-pull balance, but no adjustment for magnitude. That will have to change. Since there's no real space on the back panel or the rear underside, I'm thinking that the best solution in this case is to just build a replacement board for the bias adjustment and mount the mini-pots there. I think this is just going to be a case where I'll have to pull out the chassis when I want to do maintenance.

Let's jaw it over a bit.

As far as market research goes, ...they'd have better luck if they were trying to herd cats. ... appeal in this application if you're willing to jump over the hurdles to get there.... demographic for your target market or not.

It's always a speculation. I've done things like this a bit, so I do understand the business issues.

But - let's talk. Maybe I can make a suggestion or two for you to get to at least a better setup. It would be good to hear your feedback on it anyway.

On the biasing kit, there's already been some discussion on the sales appeal of making it easy, and while customers would love it, I suspect that techs, who would have to be the ones to put it in, would hate it because it removes a nice source of income from them if every amp is easy to bias.