G7 parts source

Hi all,
I just finished building a pair of G7 mics and now I'm about to start building the PSUs. I've done searches on this forum and I can't find anything....does anyone know a source for the PSU transformers for North America? Something that will fit on Gyraf's pc board layout?
The description of the trannys is as follows:

110:9V, ~5VA
&
220:15V, ~3VA

I when I enter these parameters in mouser's search engine for instance I come up short.
Anyone?
Thanks,
Freddy G

The transformers for the PSU don`t fit on the circuit board so any torroidal transformers that meets the spec will do. You may want to search for something like torroidal transformer on Mousers search engine, & then just find some that fit the spec.

sorry spelling should be toroidal with 1 R

look at stock EI tube transformers maybe something like a 170 0 170 (for the two diode full wave style bridge) at a few ma and 12.6 at 1amp or so. Or something at 140Vac or so four diode non CT tapped full wave bridge and 12.6 at 1 amps.

Look at the hammond site tubes and more .com etc.

You don't have to use the stock transformer setup. you might want to up the B+ or maybe even lower it you can adjust the PS a bit with the Rs in the RC sections of the PS. If you move the PS B+ V around you will want to adjust the capsule voltage. If you are using a CK12 type maybe try 45V at the center setting 90V total a k87 type maybe 60 and 120.

http://www.hammondmfg.com/pdf/5c0030.pdf

look at the 262E12 or 26f12 You can use a voltage doubler to get about 280 VDC and then bring it down with a 4 stage RC tube style PS or you could full wave the 120 for around 160 or so volts and then use a few stage RC type filter for a lower voltage.

What I do for setting up a supply for a tube microphone calculate guess the microphone B+ load, lets say 1ma. 1ma at 160V will be a 160K load resistor power needed in resistor > I ^ 2 X R (150k) use that load on the supply and adjust your series R in the power supply filter you will need to fine tune the values when the microphone is used instead of the load R.


If you look at schematics of microphone you will see 105VDC to 210VDC as the B+ Note the microphones that inspiered the G7 in the pages about it

edit

http://www.mouser.com/index.cfm?&handler=data.listcategory&Ne=3&terms=262e12&Ntt=*262e12*&Ns=SField&N=54600000&crc=true

thanks for the info gus,
I'm interested in your thoughts but I'm afraid this is technically over my head .....I'm mostly a "paint by numbers" kinda newbie and I really don't understand enough to do design tweaks to Jacob's (or much anybody else's) layout.
I'm using a soundking capsule, I can't remember the model #, it's either a 102 or 106....it's the one with the terminal right in the center of the diaphragm.
Freddy

ok....so this one tranformer does the job of the two transformers that gyraf has in his layout?
Thanks,
Freddy

Hey Freddy,
do you have a parts list for all the other components??
It will save me a lot of time...
thanks
Gil

I've sourced everything and am nearly finished my G7 build, but I've been unable to find a source for the 9-pin tube socket that fits Jakob's PCB. Can anyone help me out with a source?

Thanks.

tubes and more?

www.tubesandmore.com

under Tubes and accesories.

That was the first place I went and it looked like all the ceramic sockets had the big flat pins that won't fit the PCB. I actually have some of these in spare parts. I'm looking for the ones will the round pins.

Maybe I can just call the them tomorrow and see what they say. That's always easier than trying to tell from a tiny picture.

Hey Greg,

how many do you need?

I may have one here that I can send you. Let me check and get back to you tomorrow.

take care
Gil

I just need one for my G7... I can send you a few bucks if you want. Thanks.

Greg,
This is where I got mine.
http://www.partsconnexion.com/catalog/tubesockets.html
:sam:

wow! :shock: i'm sure they are of great quality, but $21.95 is a lot!

greg, i had the same problem with the "flat" pc legs when i was mounting them onto my G9 pcb, but i just took a pair of cutters to them and shaved off some of the width. works fine for me. :green:
-grant

dissonantstring,
Look again at "ceramic sockets" ....they are a buck and a half :razz:

hey freddy,
didn't see those. good deal on those! but those are the type with the "flat" pc legs, i thought greg was looking for round pin ones so i assumed you were refering to the teflon gold pin sockets($21.95). did those $1.50 plastic cup style have pins that fit the G7 pcb?
cheers,
grant

I got my G7 up and running so I thought I'd post my parts list. I decided to go with Nichicon PW lytics and WIMA polypropelene. I still might make a few changes, but this should be a good starting point. Do not use this as the "end all be all" parts list for the G7. There are many options for capsule, tube, caps, etc. For example, I used WIMA polypro instead of the specified polystyrene for the polarization caps. I might change these after some more listening tests. I'm sure I'll also try a Mullard for my tube.

G7 Parts List

Does anyone just jumper out the 220ohm and install a 1.8K in the 1.6K spot?

I didn't do that... I usually build projects "as-is," use it for a little while to get familiar with it, then make adjustments and listen. I actually wish I had built two so A/Bing could be done easier and probably for accurately. I did use a 200u instead of the 100u and I omitted the 1u/63V as per the PCB.

I still need to get the PSU enclosure finished. But in time I will do what you've suggested; however, my limited tube experience doesn't know what will be improved. But that's why I have eyes and a brain...