Dual Pultec Eqp1 - Power Trafos

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hotbaby

Well-known member
Joined
Jan 4, 2009
Messages
410
Location
Germany
Hey Guys,

what Power Trafos did you use for your Dual Pultec (Europe 220v) ???
two powersupply pcbs need to be fed with 15vac, 12vac and 220vac each pcb.
i can´t figure out which trafos would work fine for that  :-\...
anyone knows where to buy these transfos?
transformlk6.jpg
 
If you're building the Gyraf version, you can use two transformers: one 220V->220V and 220V->9V (12V)


Check this out:
www.musikding.de/index.php/language/en/cat/c84_Transformatoren.html

There are some suitable transformers, for example: "Power transformer 230V -> 230V, 20V, 6.3V" and "Toroidal transformer 230V -> 250V, 9V, 24V"

If you're gonna use DC for the heaters, you have to use the last one.

Hope this helps.

Regards,

Anders
 
Thanks Sredna, i think i would need

Toroidal-transformer-230V----185V--6-3V
for 6,3v

and

Toroidal-transformer-230V----250V--9V--24V
for 250v

do i need 4  peaces for one stereo pultec???  ::)
 
hotbaby:


No, you dont need two transformers for each voltage. Just wire the PSUs in parallel.

You need either one transformer with 230V->230V/220V and 9V/12V  or the arrangement
from the G-Pultec from Jacobs site: http://www.gyraf.dk/gy_pd/pultec/pultec.htm
Check it out.

I have a feeling that you're quite new to tube circuits (I'm maybe wrong...),
please read up a lot on safty advices for working with high voltages since it's
really big risks in it.

If you don't know how to correctly connect transformers with 230v and more (or even less)
you'll risk to destroy lot of expensive parts (in best case) and burn down your house, and yourself.

Please dont do that!  :'(

Take care,

Anders
 
Hey Anders, thanks for your care. yes thats my first tube build  Smiley i will be very carefully and wound do anything im not 100% sure of.
How can i get em parallel? in Jacobs pdf is only the mono chem.
 
i found this as answer for paralleling the two pcbs:

####################
I am no expert, but this is what I'd do:

1. Make sure you have a fuse before your first power transformer after the IEC inlet. Get the first unit working properly, without hum!

2. bridge the 12V secondary of the first power transformer to the second pcb and check the heater voltage on both channels and see if the transformer does not overheat or anything (be carefull!!!).

3. bridge the 230V primary of the reversed second power transformer to the second pcb and check the the B+ and again see that nothing blows up and recheck everything else.
####################
 
Be carefull when testing gpultec circuit, the big capacitors will keep high voltage for a long period of time,
especially if the tube is not plugged in the socket, I mean there will be 250-300 volts DC on the PCB for something like 1-2 hours after power off, don't touch it!
Sorry if you knew already that, a good solution is to solder a bleeder resistor across one cap legs under the PCB
(like 200k or 400k) so that the capacitors will discharge within a short period of time when power off the circuit
 
For my part, I left a voltmeter connected to high voltage rails when testing this circuit
(one lead connected/gripped to PCB GND and the other connected/gripped to one leg of the 3.2k power resistor on the PCB)
This way I could monitor the high voltage anytime (when power off, you see the voltage drops slowly until it arrives to safe value, like 50 Volts DC, so you can touch the PCB again)
 
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