Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: guitardude57 on November 13, 2017, 12:52:50 pm
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Anyone have a source for a Stancor PS-8416 or toroid, for a tube preamp power supply?
I am building a hybrid bass amp, and need PS Tranny, in a very low profile, to fit in a single
rack space and/or a small lunchbox sized head.
115V into 125-0-125 with 6.3 1 amp secondaries.
Thanks!
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Antek sells toroidal power transformers in various sizes/voltages: http://www.antekinc.com/transformers/
Some of them are meant for tube amps with 6.3v windings, but the secondary windings on those are often higher than 125v.
Were you planning to use the center tap of the 125-0-125 winding or do you need 250v? You can probably use a single 120v winding to achieve similar results with a bridge rectifier, or a voltage doubler, etc, depending on how much space/flexibility there is for the rest of the power supply aside from the transformer.
If you don't need much current, you can find a transformer with dual primaries. They're "supposed" to be used in series for 240v power or parallel for 120v power, but you can hook one to 120v power and the other can be freely used as a source of 120v AC (non-center-tapped).
This sounds really close to what you need, and might be a good solution for you. But only one of the windings originally meant as a "primary" is actually getting power into the transformer now, so you should only demand about 1/2 the power it was originally rated for. In a preamp application, that's probably fine.
EDIT: For example this one has only 6v "secondaries" (outputs) but it has 2x 120v "primaries" (inputs). If you have 120v power, you can use one of them to actually power the transformer and the other is effectively a 0-120 winding. http://www.antekinc.com/as-0506-50va-6v-transformer/
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Thanks 92volt...
One can spend hours spec'ing out trannies...
I have looked at many of my usual suppliers...alas not many choices.
China seems to have better choices. :dontknow:
I would prefer good ol' USA stuff.
40VA is plenty...
I considered a dual primary. I t would work in a pinch.
Only powering a single 12AX7, and am doing 6V DC heater.
The Class D I am using has somewhat of a share function on power,
but not what I need for 200 or so rectified volts.
Trying to keep the wiring and PS down to minimal.
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Edcor parts are made in the USA, and this one looks almost perfect for you: http://www.edcorusa.com/xpwr080
They have smaller transformers, down to PCB-mount types... but while small, I'm not sure would be very easy to work with. They're also made-to-order and take a long time to arrive.
Hammond transformers sometimes have dual primaries.
It will probably be easier to use the 12AX7 heaters in 12v configuration than 6v, unless you have a good reason to use 6v. I've been looking for filament transformers recently and it just seems easier to find 12v or 12.6v models than 6v/6.3v.
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Using a 6 volt regulator on the board for the heaters, so can use a wide range of voltages to the Reg. But will keep the incoming no higher than 8 volts, to keep the heat down...
I will check out the Edcor link. Thanx!
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hammond 261C6 should work: it is 1/8" narrower than the stancor part, however, it is dimensionally different in width, height and mounting centers.
Hammond part:
http://www.hammondmfg.com/261.htm
stancor part specs attached.
--pete
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dang! 45 bux. damn thing made of gold? looks like the hammond or wait 8 weeks for the made in new mexico part...
https://www.tubesandmore.com/search/node/261C6
--pete
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Wow, gold wire in there...lol
Even the Edcor is an 8 week wait. At 22 bucks.
Looks like I should just make my own... :BangHead:
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use two PT. one for heaters, the other can be a small isolation.
heaters:
166N6 25.2VA: 115V 60 Hz Pri: 6.3VCT 4A Sec: Size C9H.
166L6 12.6VA: 115V 60 Hz Pri: 6.3VCT 2A Sec: Size C7H.
low profile - fabricate a 1/16" or 1/8" G10 PWB carrier to attach PTs and mount carrier to chassis.
power:
229B230 12VA: 230VC.T. 50ma in series, 115V @ 100mA in parallel.
heaters:
229B12 12VA: 12.6V C.T. @ 900ma in series, 6.3V @ 1.8A in parallel.
229C12 24VA: 12.6V C.T. @ 1.9A in series, 6.3V @ 3.8A in parallel.
--pete
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> single 12AX7, and am doing 6V DC heater.
Triode Electronics has a Dynaco preamp replacement PT. Stock it powered four 12AX7 and a +/-11V DC heater string. More than you need, which means it won't run hot even in your too small box. It has been a very long time and I do not recall if this part would fit in 1U; I think the inches are on the product page. EDIT-- ahh, kinda big (http://store.triodestore.com/pa2powtrandy.html).
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Yeah, not alot out there available, sooner than months... to wait.
The amp module I am going to use, does have a 45V tap... and a 12V too.
Maybe a 3:1 tranny, and rectify for HT, and the 12V for supplying my 6V regulated DC supply for heaters.
May not need a PT, as long as there is a few mA to swipe.
The PS for the amp module is a high switcher, so from 100V to 240V it sets up to function the amp at
full capacity.