Tade no tube amp!

[tade]

So I am building a set of speakers which use altec 288c compression drivers with 115db of efficiency, and of course getting ahead of myself. These are playing above 500hz so i figured a tube amp would be a great project because I wont have to build a monster!

The speakers are 24 ohms and I own a pair of hammond 1609 output transformers which I would love to use:
http://www.hammondmfg.com/1608.htm

Looks like they recommend push pull, but i have heard good things about single ended designs...

so basically all i am asking is for you to design a tube amp for me! Or point me in a good direction please...
: )
Thanks

BTW stay with this thread, you will not be dissapointed.

[valveitude]

http://www.sempermusica.com

[tade]

those chokes seem a tad expensive, is that the name of the game? : )

[SHiFTY]

Those transformers would be perfect for a 6V6 push pull ultralinear (PP UL) design. You cannot use them for single-ended, because they are a different design (SE has an air-gap.)

6V6 is the smaller brother of the 6L6- preferred due to its higher power. However, the 6V6 sounds better, and is far cheaper to find NOS as many of them were produced for radio outputs.

You could also use EL84/6BQ5 push-pull.

Have a look at http://www.bonavolta.ch/hobby/en/audio/6v6_2.htm or
http://www.bonavolta.ch/hobby/en/audio/el84_6.htm for examples of simple PP amps

This would probably sound ok. Really you can use just about any PP design for a 6V6 or EL84, they aren't too hard to drive.

Just for a laugh, check this out: 101 6V6s on ebay! (not mine)

eBay

[tade]

looks good to me, should i bid?!

Imagine a tube driven line array or some high end driver. with a separate amp per speaker, Sweet!

Thanks for the links, more reading!

[planet10]

check out Eli's El Cheapo amp...reference to it here & on the Decware forum. Dhaen also started a thread here on a souped up one.

I'd think best would be a small OPT SE amp using a trioded EL84/6V6...

dave

[tade]

I would have to pick up different trafos? That isn't too big a deal though then this turns into any number of SE n008 threads on here...

But wait! this one is mine!

thanks for the info guys!

[planet10]

Originally posted by tade
I would have to pick up different trafos? That isn't too big a deal though then this turns into any number of SE n008 threads on here...

In an SE amp a large OPT is required to get good bass... as the size goes up the HF extension decreases (this is a generalization there are lots of other factors), so looking for some tiny EL84 OPTs from an old German hifi would be where i'd be looking (actually i already have a set from a Grundig). Pic is of a set of Nordmende (a bit larger than the Grundigs). The quality of construction is typically very high and they can be found cheap ($20-40/pr in my experience)

Typically thou these are 7-10k into 4 ohms so with your 24 ohm speakers you would have a huge reflected impedance -- but this might let you look at some unusal output tubes... like 12B4, 12BH7 (i don't know what these need but you get the idea). These typically have higher mus -- you might get away with a single stage amp. Add a small coupling cap up front to set the XO frequency and away you go.

dave

[tade]

you know i might actually have a pair of trafos for this very task. unfortunately they are at home so it will be a few weeks till i can get them. Ill keep in touch.
Thanks

[planet10]

not the 12B4, even 12BH7 & 12AU7 have Ra lower than needed if you follow the 2.5-3.5x rule of thumb -- at least for the pictured OPTs (you'd want 12-20k Ra for a 24 ohm load)

dave