Edcor transformers

I thought would ask this here since a number of you have had experience with edcor transformers. I work at the Christchurch Polyech Jazz School in Christchurch New Zealand. In our building we have a recording studio built onto the back of our auditorium. This gives us the ability to use the large auditorium space to record in and also the ability to do multitrack live recording of the performances in the auditorium. Currently we have a simple passive spit wired into the front of house box to run the mic signals to the recording studio for the live recording but this has given us ground loop issues which was to be expected. We were able to fix the ground loop by running the gear in the studio from the same power point as the front of house pa but this involved running an extension cord through both doors and down the hall which wasnt very elegant. The other way we solved the problem was by borrowing some transformers and using them on the lines running to the studio. I know there will always be some loses involved in using transformers but it seemed to fairly minimal and did solve the problem completely. So my question is would the edcor WSM 150/150 be suitable for this? Edcor say it would be fine (and it fits in our budget which isnt much unfortunatly) but i thought I wold ask here for opinions before ordering 24 of them.

Cheers
Dave Cooper

It sounds to me like lifting the cable shields at either the recording room or the FOH (but not both) is likely to solve your problem. Give it a try on a couple of lines and let us know.

The shields on the connections to the studio were disconnected from the get go and didn't make any difference.

OK, then. When you say "passive split", is it transformer-based or are the three lines just spliced together?

The three line are just spliced together. I know a transformer split would be the best way to go but the cost is beyond us. I had hoped simply isolating the feed to the studio with impedence matching transformers would be a simple soloution. It worked fine when I borrowed a couple of trasformers to try it out, no more earth hums and buzzes and no huge drop in quality. I have read that the edcors aren't everyones favourite transformer as far as colouration goes but they fit our budget and heck the colouration might just what we need

Cheers
Dave

Do you have the mic pre's out on the floor?
You are not running the mic signal all the way to the preamp in the control room, right?
what kind of preamps?
Some output devices do not like a lot of wire.

What kind of mics?

You need 150:150 mic level shielded transformers for this purpose. Better to use mumetal or permalloy core. Expensive.

You could try the OEP wired as 600:600 for a cheaper transformer.

Or maybe edcor can wind small permalloy transformers for you for a nice price, and you would put them in metal shields. In a passive system, it doen´t really need to be mumetal shield. I think iron will do it well. Just keep all the transformers in a nice grounded iron case, and keep the system away from magnetic hum sources, like big power transformers in other boxes...

Bassically this is what i want to achieve and I want to know if edcor have a transformer that will do it (as their prices look to be the only ones we can afford) or if anyone knows where I can get some cheap (yes I know they wont sound as good as jensen, stower etc etc) transformers to do this.

Cheers
Dave Cooper

The WSM600/600 will do it. Just be sure to enclose it completely in a steel box.

(I say WSM600/600 instead of the 150/150 model because the primary inductance on the former is just high enough to not load down the mic excessively. This is probably not the case with the 150/150 model, assuming it's the same transformer only with half the turns).

I would sample a transformer first, since you are doing 24.

How far is the mic from the control room?
50 feet?
50 yards?

Maybe build a box with 12 5534's.
1:2 buffer. (line loss)
Could be battery operated to avoid pwr supply ground loop trip cord.

No, then you have common mode output, bad cmr all the way back to the booth.

Maybe a sub mix board set up near stage if you have one in the basement. Get levels about,right and do final mix from room.

Cheers for the help those were the answers I was looking for! As far the length of the mic cables go they arent that long as the control is built right behind the stage so the mic lines only have to go about 4 metres trough the wall to get to the rack mount micpres (2xsytek 4 channel and 1 arx 8 pre). It was built with windows between the control room and the stage so that the auditorium could serve double duty as both concert venue and recording space. When we have a concert the windows have shutters and curtains over them so you wouldnt know the were there otherwise.



Sorry for the tiny image it was the only one I could find. The shutters are closed but the curtains aren't pulled

I will order one just to try and make sure we wont have any unforseen problems. I should be able to purchase a good steel box locally to put them in.

Thanks heaps
Dave Cooper

[quote author="xldave"]I thought would ask this here since a number of you have had experience with edcor transformers.....Cheers
Dave Cooper[/quote]
Out of interest, have you tried your friendly local transformer winder ?. Transformer Winding Services (imaginative name, huh) in ChCh have done some decent big toriodal power trannies for me - maybe they do audio stuff as well (I've never asked). Marque Magnetics in Auck definitely do make 600/600 audio stuff - Oreania use them in their ampracks. Then again the Edcor prices sure do look decent, so I would be interested in hearing how they stack up against the "recognised" brands (Sowter/Jensen/Lundahl) as well. The best audio trannies ever made in NZ came from Teleco (Lower Hutt, decades extinct) and these are assiduously collected and treasured by people in the sound reinforcement industry.
M

Hadn't really thought of looking locally I will ring round and see what i can get. Heck if oceania thinks they are decent then thats good enough for me plus i have always been a fan of buying NZ made gear.

cheers
Dave