nashkato

ps for G7 : supplyvoltages quite low : why , any loss?
« on: February 14, 2008, 08:44:35 AM »
well , i got 2 capsules from dale (they sound great, like them better than the sparepart ck12 from akg).

in my ps i got 125 V loaded on the anode of the ef86. i know 20% tolerance in tubegear is usual and mine isn´t far away from that border and the mic works as far as i can say well ,too.

-are there any problems in running the mic permanently with this voltages.?

-how could i rise the current.? (already did the 5K suggestion)

-why is it that low.? (it´s a double ps and the second one has better voltages (about 150 V loaded) it´s the same 9V toroid running into 2 different 15V toroids(one has got 7,5VA the other 3,2VA) are there that great tolerances in manufacturing?)(supply from the power station?)


steppenwolf

ps for G7 : supplyvoltages quite low : why , any loss?
« Reply #1 on: February 14, 2008, 10:21:46 AM »
Hi!

I experienced similar things when using back to back transformer configuration.
I once  bought two 10VA 230-12V trannies of the same brand and wired them back to back.230-12 into the 12V secondary of the second one and I got out 220V aprox. I had another transformer laying around that was 230-12V, too but a different manufacturer. I hooked it up the same way and I got out 180V. I think that back to back just isn't so well calculable when you use transformers not made for that purpose...
My suggestion is to use a 12V-230 tranny instead of the 15V-230V configuration. This should rise your voltages!

Have a nice day!
Stefan

Gus

ps for G7 : supplyvoltages quite low : why , any loss?
« Reply #2 on: February 14, 2008, 10:37:35 AM »
Do a search for G7 power supply this seems to be a common problem.  I am not a fan of back to back transformers.

steppenwolf

ps for G7 : supplyvoltages quite low : why , any loss?
« Reply #3 on: February 14, 2008, 10:39:53 AM »
Me, too!
There are several manufacturers of custom transformers that don't take too much money from you and you can specify the secondary voltages!
Greets

MrZpliff

ps for G7 : supplyvoltages quite low : why , any loss?
« Reply #4 on: February 22, 2008, 03:08:46 PM »
It seems toroidal transformers works better backwards....  :?

I had the same problem with my G7-psu. Not enough voltage, though the transformer had the right specs. Changed it to a 15V toroidal and no problem !
Peace
Magnus
www.bitterend.se

Gus

ps for G7 : supplyvoltages quite low : why , any loss?
« Reply #5 on: February 22, 2008, 03:34:56 PM »
I don't think it has anything to do with the core shape.

If I cared I would measure the transformers that work and find
The real VA rating
heat rise differences
wire size and/or resistance


 

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