what's the most mass produced small transformers in addition to wall warts?

[jibberish]

just slinging more mud at the walls, getting things thought out.

i see 16v doorbell xformers for $5  8:1 is too high of a ratio to use 1 backwards though.  2 could be used a la wall wart powersupply

what is a common use 30v transformer?  backwards it would be a nice 300vac. then use a regular 12vdc wallwart straight up for Vg

also i need to look into the actual rectified DC value from an AC source.  the radical2 sinusoidal RMS bullshit...
Any shit HP(hi pressure like metal halide or sodium etc) lighting ballast for 110 is a 2:1 step up since all those lights run on like 220v.
so i need to determine: is rectified 220ac enough to get the big dc to acceptably power tubes to the sweet place on the load line curves. mercury vapor ballast xformers are dime a dozen and actually can handle some power

edit: 1.4 x 220 = 300-ish

[dunwichamps]

maybe this help, idk

https://taweber.powweb.com/store/pdlptsch.jpg

[rayinreverse]

I have lots of 24 v transformers,but never seen 30v.

[jibberish]

heh, i cant think of any 30v ones either,
but after considering the rectification voltage boost some more, i'm thinking a 48v would actually be more suitable

some 2.2/1 or some such thing so that would give like 240vac and then about 340vdc rectified. that seems like a nice HV range.

i definitely want to look into what runs a w/e 50-70 watt mercury vapor lamp. small POS transformer, but it passes enough for some watts and losses. you get the whole light and fixture for $29 "complete with dawn dusk sensor" O8.

wtf are in shoplamps?  $7 shoplamp has an itsy PCB with some components on it including a transformer. flourescents use higher voltage less current..this is fucking $7 including stamped metal, 4 bi-pin T12 sockets, the PCB, power cord AND and accessory bag of useless hanging chains....and a box....those might be perfect as is...

i'm kind of making up my own homework here aren't i?   

[Hemisaurus]

What are you looking for? Power transformers? If you can find alternate output transformers, that's where the money is lost, a typical output xfmr is going to be anywhere between 2K and 5K to 8 so that's 2000:8 or 250:1 winding. So if you find any 120V in 1/2V out transformers, you're in business.

[jibberish]

well, you are corroborating what i've been finding. ya, i have a million 1:2 std xformer options for the HV part.

heh, even that ant amp has a bogus op transformer..like 50k  to 4,8,16ohm taps on the other side

[jibberish]

yep yep yep...it's ALL about the OP transformer isn't it?   =damn!

edit:  ok i think im using a 12au7 in place of the 2nd 12ax7. from reading
this guy's article, and seeing what he went through with the 12ax7, au7 and at7, just as a starting point
http://music-electronics-forum.com/t20518/
it looks like the circuit IS set up for the au7 which is a "current driver" moreso than the 12ax7 voltage/pre amp stuff


im seeing why so many people use those 5watt tubes: the OT is easier to get.
BUT, i'm really intruiged with this sub-watt stuff to start with. the killer ant sounds pretty good even tho it is mass produced full of cost-cutting corner-cutting.  so does this look like something i can sub in for a 50k/16ohm OT (25k/8ohm=hammond 125c)
http://angela.com/hammondoutputtransformer125c.aspx
fwiw, angela flat out blows digikey away on the pricing.

[Hemisaurus]

$2.69 from RadioShack, can be used as a very low wattage OP xfmr. 1K:8ohm or 2K:16ohm if you prefer.



May be useful, I remember reading an article from an Australian who was using something like this, I'll hunt for the URL.

[Hemisaurus]

http://www.ozvalveamps.org/optrans.htm

Untested by me, use at your own risk

[jibberish]

thx chief, i favorited it.
   the problem with the ant circuit is they  use tubes with high impedance.  that hammond 125c transformer is about the highest impedance primary i could find(25kOhm/8Ohm), and heck with the 16ohm speaker out.  i hope i can make that work with the 12au7 tube which seems like a nice fit for the ant circuit bias setup instead of that 12ax7.

i hope i'm understanding that the " maximum power transfer" rule still does best when impedances are matched.
i have to re-read the impedance calculation info a couple more times yet too.

If so, this would put me at $60 for that op transformer and the 2 groove tubes i think i want to use.  that would keep the whole deal under $100 in parts. but more importantly, it is a currently mfrd "in-stock" item

[Hemisaurus]

My worry would be that single ended xfmrs need an air gap to prevent core saturation, so repurposing these might not work, the little one because it will work at lower voltages OK, but at higher ones not so much, and the larger one, because they were being repurposed in a push-pull circuit which because of the opposing voltages in the primary, doesn't need an air gap.

[jibberish]

there is no question, life gets easier on the op when the tubes intended for current drive are used.
like a fender replacement guide i saw..goes down the whole line of tubes and specs out an op xformer for each type

it does seem that with this 100mW stuff some crazy stunts can be pulled, like running speakers from a high impedance voltage driver wtf lol. maybe that's why this whole ant deal intruiges me so much. it's so fucked up.
i'm sure blackheart ordered a custom xformer run from some OEM mfr.   50k:16ohms is a lot of turns to get that high value on the primary

i'm actually going to put some time into studying the classic amp topologies now, and get real comfy with the commonly used tube types.   so if i see "marshall tone stack" vs "tweed tonestack" i'll know what's up, or whoever's 2 stage pre, etc..all these amp builders borrow chunks of classic amps. i'm guessing this will help immensely with the big picture.

then my next round of questions will be one notch less noobie

[Hemisaurus]

Well the milliamp uses a 12DW7, which is half a 12AX7 and half a 12AU7, so you can have a voltage gain and current drive in the same tube. He's using a 5K to 8ohm transformer on a 12A triode.

The transformer he used is about $13 from tubes and more and is an 8W SE xfmr.

Weber do a flea output xfmr that has a 4K and a 1.5K primaries and 8 and 4 ohm secondaries, for $8.

If you get really desperate, or cheap, you could try feeding a xfmr with a xfmr a 100:1 turns ratio feeding another 100:1 turns ratio and you have 10,000:1 if my maths skills are still sharp.

[neighbor664]