Hammertone Viper

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Hammertone Viper

Postby dhuebert » Tue Dec 13, 2005 12:45 pm

www.diytube.com/forumpix/viper_in.jpg
www.diytube.com/forumpix/viper_out.jpg
www.diytube.com/forumpix/viper_under.jpg

Some snaps of my lastest bass amp. This one has a bootstrapped input for piezo mike for use with acoustic basses, see below:

http://www.drangers.ca/muckbucket.html
http://www.drangers.ca/promo2_high_res.jpg

Schematics to follow

Don
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Re: Hammertone Viper

Postby Shannon Parks » Wed Dec 14, 2005 7:10 am

dhuebert wrote:Some snaps of my lastest bass amp. This one has a bootstrapped input ....


Very cool, Don. Is this schematic similar to your first one?

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Postby dhuebert » Mon Oct 23, 2006 8:36 am

Image

Image
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Postby EWBrown » Tue Oct 24, 2006 6:14 am

Very nice! I like the idea of building it into the wooden tool carrier.

One small precaution, I notice that you are using the chassis as a common ground return (most terminal strips), that can and will work, but a mechanical connection can eventually go bad or open, I'd suggest running a buss wire to all the mechanically grounded points, and back to the filter cap's common (negative or can) connection just for safety and that last little bit of noise elimination.

edit: 10-25-06

I've seen this "chassis ground" scheme used in plenty of comercially made gear, and is common practice at radio frequencies An H H Scott 310 FM mono tuner that I have, uses a copper plate "sub-chassis" as a ground plane, and there are a LOT of components and connections soldered to it, and the unit works and sounds very good. At RF frequencies, short and direct connections are a must, as lead length equates to increasing inductance with increasing frequencies, , and can cause all sorts of weird instabilities on their own.

I've seen sticky-back copper foil (or think of it as wide copper tape) at hamfests and surplus shops, and I've picked some up to experiment with, with the intent of sticking it under the top of the chassis and trying to use it as a ground plane, with direct solder connections as needed. I also thought of trying it as a chassis top cover, but it does scratch and mar very easily. Even a fingernail can leave a hard-to-remove mark in it.

/ed B in NH
Last edited by EWBrown on Wed Oct 25, 2006 5:22 am, edited 1 time in total.
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Postby dhuebert » Tue Oct 24, 2006 11:58 am

you are using the chassis as a common ground return


I'm going to have to take another look at it. These are old snaps and alot of changes have occured since then.

In this shot you see I have used the terminal strip grounds in three places: the resistors for the filaments, a couple of shields and the single point ground for the input. The shields don't matter but the other two could be a concern. I can solder the filament resistor strip to the chassis but the input ground could definitely go elsewhere.

This amp was recently used in the recording of a bluegrass album. The musicians were very satisfied with how quiet it was, but I feel there is still room for improvement.

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Postby Uncle Ned » Fri Oct 27, 2006 9:06 pm

dhuebert wrote:
This amp was recently used in the recording of a bluegrass album.


Ya know, I was looking at that case (an old milk-bottle carrier?) and thinking "that looks like an amp a character from Corner Gas might play". Yellow_Light_Colorz_PDT_12

I like those vintage marbled rubber floor tiles.
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Postby dhuebert » Mon Oct 30, 2006 8:25 am

http://www.drangers.ca/promo2_high_res.jpg

The amp is for the "bass". I started listening to these guy's in '99 and always felt there was something missing from their live sound.
I suggested a tube amp with a piezo mike. I looked and looked for a suitable box to put it in and one day found it in a junk store owned by a friend of mine.
It was actually his tool box. He didn't want to sell it at first but the right offer convinced him.
I took it home, dismantled it and cleaned it with TSP. Had a chassis custom made and the rest is history.
The D. Rangers don't leave home without it.
I went to their show on Saturday where they were playing it thru an Ampeg 8x10; sweeeet!
They typically run it with the volume at around 3 o'clock which tells me there is not enough gain in the front end.
With enough signal it makes 100W RMS into a 10 ohm resistor.
Anyways, my next project is a guitar amp for these guys:

http://www.winnipegblues.com/perpetrators.htm

I've already got the wood for the box.

Don

BTW I think those tiles are asbestos.
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