Correct lamp for old Dyna-Bass

[arcsound]

My Dyna-Bass head, circa 1968, is missing the power indicator lamp. It is a bayonet style, similar to the standard 6.3 V, Fenderesque lamp (#47), in form factor and size, but is much lower in power rating, as there is a 22K resistor in series with the lamp, across the mains voltage. If I assume a 10VAC bulb that would imply about a 5K resistance, so the total draw would be 22K + 5K = approx. 4.4mA! What old bulbs work at this current level?

[Enzo]

Don't assume that. My working assumption would be it took a neon lamp, not incandescent.

http://www.mouser.com/ProductDetail/JKL ... r4GOAvU%3d

[arcsound]

That must be it. Thank you! I could not make the numbers work using an incandescent model, and did not know that neon was available in this form factor. Brilliant!

[Kagebunshino]

Hey man. If haven't still found the solution for your problem you should check this guy's article:
https://www.talkbass.com/threads/revivi ... s.1012787/
It's rly indepths, hope you'll find the information you need

[Enzo]

Hello Kage
That is an interesting article, however it is about the DYna-Bass bass guitar. The item we have been discussing is the Dyna-Bass amplifier head. A very early Peavey design. Like 1969.

[arcsound]

Got a neon bulb in the bayonet form factor, and it works perfectly. Mystery solved. Thanks!
So, in the end, after going through this amp from stem to stern, removing the half-dozen finish nails and brads floating around in the chassis, as well as candy wrappers from some long gone factory, and a hand-written map of the Monticello / Michie Tavern / Carter Mountain area in Albemarle Co. VA, this amp put out a solid 75-85 W. into a 6 ohm resistive load without starting to clip, all with original components. It looks like nothing has been changed on this amp throughout the years, no signs of soldering repair, no components with a different age pedigree. The power supply rails are rock solid, at +/- 40VDC. Even the EC filter caps are original (I brought them up slowly, over many hours, using a variac). I was not expecting this, given the '67 and '68 date codes on the output transistors. This is one ole gal. Could've been at Woodstock....

[Enzo]

Hi new guy...

Peavey does make a nice Dynabass guitar, but they also made an amplifier called Dynabass in like 1969. That amp is what we are discussing.