Jim50hertz
Well-known member
cool 
MK-U47
- Thread starter ioaudio
- Start date
Help Support GroupDIY Audio Forum:
Could be nice, i'm sure there will be some demand, as when Moby / Kingston did them for the MK7.
Kingston
Well-known member
Jim50hertz said:
2-watts is not enough. Remember we're also supplying some heaters with this PSU. 1k resistance with 100mA calculates to 10watts. Even if the tube's don't actually draw that much current big resistors are needed here nevertheless (safety). Realistically we're talking 3-5 watts minimum, based on the values ioaudio used here.
LED doesn't need to be particularly high power, standard stuff will do. If you leave it out just remember to connect the 100k to ground because it's also a bleeder for the big caps.
Kaspar
Active member
So I just get a call from Paypal, (why would they be calling this late?, I think to myself). A very nice woman named Beth asks me if I had indeed authorized a payment on 9/21 to someone in Austria. I explain that I had and asked if I could be of any help. It appears some sort of red flag went up when they saw multiple payments for something called an MK47......
I explained, that we were a bunch of nutcases who like to build our own audio gear (which she found very interesting) and I did my best to quickly explain what a tube mic was. I then told her to rest assured that the 40 or 50 payments going to Austria were for mic kits, not small arms We both laughed a lot
Max, I'm guessing that next time, a small amount of thought should be put into a kits name. I wouldn't offer the RPG47 DIY KIT for example, it seems to worry the good folks at Paypal! ;D
Nice to know Paypal is keeping their eyes open
Kaspar
I explained, that we were a bunch of nutcases who like to build our own audio gear (which she found very interesting) and I did my best to quickly explain what a tube mic was. I then told her to rest assured that the 40 or 50 payments going to Austria were for mic kits, not small arms We both laughed a lot
Max, I'm guessing that next time, a small amount of thought should be put into a kits name. I wouldn't offer the RPG47 DIY KIT for example, it seems to worry the good folks at Paypal! ;D
Nice to know Paypal is keeping their eyes open
Kaspar
craptical
Well-known member
Kaspar said:
Nor the AK47 kit...
ioaudio
Well-known member
Kaspar,
sorry for the unconvenience - and thanks for taking your time explaining beth what she needed to know.
Strangly they didnt contact me in the first place - but simply frooze my account.
The name MK47 is derived from my name + 47
@ all:
thanks for your quick payments! if for some reason you appear in the list of the first post but did not receive a paypal request pls let me know.
-max
sorry for the unconvenience - and thanks for taking your time explaining beth what she needed to know.
Strangly they didnt contact me in the first place - but simply frooze my account.
The name MK47 is derived from my name + 47
@ all:
thanks for your quick payments! if for some reason you appear in the list of the first post but did not receive a paypal request pls let me know.
-max
Some suitable PT at Mouser for this project... All are 115/230V primary for international use. All are 230V secondary, so one have to scale down some resistors.
Hammond low profile 12VA (PCB mount) : http://fr.mouser.com/ProductDetail/Hammond-Manufacturing/229B230/?qs=sGAEpiMZZMv4oUrzpPKU3DNexajFS1TgVfTHsC9oByc%3d
Edit : Forget this one, too weak for the job!
Hammond standard 25VA : http://fr.mouser.com/ProductDetail/Hammond-Manufacturing/185C230/?qs=sGAEpiMZZMv4oUrzpPKU3DNexajFS1Tgk677ZWfOnzo%3d
I have not tried this transformer myself but I had at least one report that it produces some mechanical hum. So, maybe this Hammond is not the best choice.
Triad Magnetics toroid 25VA : http://fr.mouser.com/ProductDetail/Triad-Magnetics/VPT230-110/?qs=sGAEpiMZZMv4oUrzpPKU3A2NOXuypJmAdyV%2fyMYGF1Y%3d
Prices are and €11.34, €14.12, and €16.24.
Axel
Edit : Forget this one, too weak for the job!
Hammond standard 25VA : http://fr.mouser.com/ProductDetail/Hammond-Manufacturing/185C230/?qs=sGAEpiMZZMv4oUrzpPKU3DNexajFS1Tgk677ZWfOnzo%3d
I have not tried this transformer myself but I had at least one report that it produces some mechanical hum. So, maybe this Hammond is not the best choice.
Triad Magnetics toroid 25VA : http://fr.mouser.com/ProductDetail/Triad-Magnetics/VPT230-110/?qs=sGAEpiMZZMv4oUrzpPKU3A2NOXuypJmAdyV%2fyMYGF1Y%3d
Prices are and €11.34, €14.12, and €16.24.
Axel
And while we are at ordering some iron, you might want to consider one or two of these 10H chokes : http://fr.mouser.com/ProductDetail/Triad-Magnetics/C-7X/?qs=sGAEpiMZZMsg%252by3WlYCkU3Estp%252bO%2f4X7zM9tbX1lwKY%3d
in order to get closer to the original NG PSU...
Axel
in order to get closer to the original NG PSU...
Axel
Attachments
Sorry I'm new here, maybe I lost something...
I'm interested in a kit, I emailed you but received no answer.
I replied to the post but still no answer..
I don't have your paypal account for the deposit.
How much is it including shipment and paypal fees?
Please help
M
I'm interested in a kit, I emailed you but received no answer.
I replied to the post but still no answer..
I don't have your paypal account for the deposit.
How much is it including shipment and paypal fees?
Please help
M
mbdonna said:Sorry I'm new here, maybe I lost something...
I'm interested in a kit, I emailed you but received no answer.
I replied to the post but still no answer..
I don't have your paypal account for the deposit.
How much is it including shipment and paypal fees?
Please help
M
Welcome to the forum. Well first batch is sold, so for receiving an answer to your mails, the second batch must be up and running, and then you'll have an answer with a paypal invoice to pay.
Prices and all infos are on this thread, read it.
zayance said:mbdonna said:Sorry I'm new here, maybe I lost something...
I'm interested in a kit, I emailed you but received no answer.
I replied to the post but still no answer..
I don't have your paypal account for the deposit.
How much is it including shipment and paypal fees?
Please help
M
Welcome to the forum. Well first batch is sold, so for receiving an answer to your mails, the second batch must be up and running, and then you'll have an answer with a paypal invoice to pay.
Prices and all infos are on this thread, read it.
Thank you for your reply, of course I read the thread before posting
..just shipment and pp fees seems are not being mentioned anywhere..
Good to know is just a question of time for the next production batch.
Greeting to all and thank you for your patience
M
for me it was 253 Euros at the end, put your location on your profile, it's better
Yes that's why i gave you my final amount, i'd say roughly, 10 euros of PPfees, and 15Euros for Shipping.
Kingston
Well-known member
mad.ax said:
Good find sir! I didn't know there are cheap 230VAC secondary transformers like this. I have needed similar ones for my own projects for a long time and always needed various hacks for this in the past.. That 12VA model won't quite have enough current for this mic, but the 25VA models are both just perfect.
Large collection of high voltage Hammond chokes here by the way, http://uraltone.com/kauppa/index.php?cat=c3_-b-Transformers-and-chokes--b-.html&XTCsid=godaqrmle89ku5r9m83ngeoge5
Oddly enough that Triad choke you posted above has no max voltage rating defined anywhere. It's very cheap, but is it safe enough since we don't know if it will handle 280-320VDC present after the first filter cap...
Kingston said:
My bad! I roughly estimated that 12VA could fit the bill based on the 40mA consumption of the U47, but calcul and sim shows that we need a bit more...
So let's forget the 12VA, I never liked PCB mounted traffos anyways!
Good find too, Sir! Pretty big choice there, and almost the same price than Triad. Keep in mind that Mouser's prices are excluding VAT or importing fees. So the Hammond are less than €3 more expensive...
The datasheet says 1.5KV hipot tested, and the size is about the same than the Hammond 157M (8H/100mA) so I guess it should do the job... But better be sure than sorry, Hammond seems a good choice!
Axel
Kingston
Well-known member
mad.ax said:
Well a good answer is that it might have barely enough juice for the mic. But this is DIY and we don't have to care about the €2 saved (compared to a bigger trafo), and safety is more important anyway.
mad.ax said:
oh, didn't know this terminology "hipot tested". Does 1500VRMS then translate to 1500VDC also? Would seems it's much better spec than any of those Hammond.
