The Amp Garage

My Oliver G-300 uses a 6AN8A in the configuration discussed. A really nice amp. As I could find no schematic for it, I made my own and put it in a CAD drawing.

Jack

Please post your schematic, as I would like to see your heater voltage doubler. I've just buttoned up my Guild Thunderstar, and was intrigued by the doubler in the power supply. 190vAC rectified/doubled to 490vDC. I would like to compare the two, plus I'm always interested in amps built around nice ...

You'll find any and all of your tubes on eBay, if you need replacements. Wouldn't be a bad idea to get extras for the ones that you use. Typically, old radios did not use a power transformer. Just rectified the incoming line voltage. To be safe, you will want to get an isolation transformer. What ar...

Here's the thermistor that I've been using on my Ampeg restorations, as well as my recent breadboard build: http://www.mouser.com/Search/ProductDetail.aspx?R=SL22_12103-Bvirtualkey58240000virtualkey995-SL22-12103-B It's 120 ohms, cold. At max current, it drops to .9 ohms. And at 50% current, 2.25 oh...

Though I haven't snapped a picture of the rectifier board, here is a drawing of the wiring, and the placement of the diodes and jumpers for the full-wave rectifier. Please check my full-wave layout and comment on any errors or improvements. Thanks.

Jack

On the pre-'65 models that I have, the hot wire goes to an eyelet on the board. A thermistor jumps across to the opposite eyelet, and out to the PT. I have a '60 model amp that was upgraded in '68 to a '65 circuit board type, and does not have the thermistor. I added one, as I like the soft start th...

Well, I managed to complete the transformer wiring, out to the topside. Filaments were the last, 5v-CT, 6.3v-CT, and 12.6v-CT, to complete this task. I foolishly thought that I would have time to maybe wire up the rectifier board, and actually try something out. Maybe tomorrow morning. Little by lit...

I'm on 2nd shift (for some unknown length of time) working startup on our Unit 2, at the power plant. Not getting a lot done, but it works better than long hours on day shift, like most of the Spring has been. I managed to get the PT output wires brought out to the barrier terminal strip on the side...

yours is way cool, inspirational, im saving photos :wink: Here's a PDF with the individual boards. I've included a concept of their layout, before I built. It's obvious from the build that I changed my mind a few times. On the next one (I've got another panel just like this one), I've got a few imp...

Wow! That's very nice! I've wanted to build such a device as this for quite some time...and wondered how I would approach such a project. It's great to see such an inspiring example! Inspiration at times comes from from the examples of others. Mine did. And, the fellow that inspired this one is app...

Very sharp! and really cool that you are "repurposing" some cast off equipment, have done some of that myself and it is very satisfying to make something useful from stuff that was headed for the landfill. Yeah, the guys at work have known for a few decades that I'm a scrounger and a packrat. Here'...

armillary wrote: I hope you'll find room for a plug-in board with a Loctal socket or two.

I've some of those tubes. Actually, quite a lot, and I've never sorted through them. I should look for some of those sockets. The boards are way easy to make.

Jack

Now that it's built (for the most part), it wasn't that bad. I work at a rather large power plant (coal fired), and we are in a very major outage, where we rebuild/repair/replace everything that needs attention. Along with this, there are some serious scrap materials to be had, if one is willing to ...

I am hopefully in the finishing stages of my breadboard. I've read a number of accounts, of other builds. And, those really got me to thinking. Never enough, though, to motivate me to build one. But, a fellow over on the Hoffman Amp site (Silvergun) posted two of his builds. I missed his first threa...

One being the inrush at power up means you may have to up the rating of the time delay fuse in the supply. Fuse the HV correctly & it won't be a problem. I stocked up on thermistors to handle this chore: http://www.mouser.com/Search/ProductDetail.aspx?R=SL22_12103-Bvirtualkey58240000virtualkey995-S...