Re: HAUFE BV107 original Neumann KM84 transformer GROUP BUY CLOSED!
« Reply #60 on: January 11, 2019, 05:09:24 PM »
I'm really excited how they sound compared to the cinemag.

Do you think there is so much difference? Is it clearly remarkable?

Maybe there are people interested in arrange a second round of these transformers...


TillM

Re: HAUFE BV107 original Neumann KM84 transformer GROUP BUY CLOSED!
« Reply #61 on: January 11, 2019, 08:34:28 PM »
So guys, I can confirm that the Haufe fits Banzai's PCB.
The only thing is, that you have to extend the transformer cables, cause they are really short.
Put everything together 10 minutes ago and it works perfect.
Was to lazy to bias the fet right now, but will it do another day.
Tomorrow I can test it together with the cm5722 transformer.

[silent:arts]

Re: HAUFE BV107 original Neumann KM84 transformer GROUP BUY CLOSED!
« Reply #62 on: January 12, 2019, 03:29:21 AM »
Maybe there are people interested in arrange a second round of these transformers...
Good luck. I was on the phone with Haufe yesterday
(since I'm still waiting for transformers I ordered in July).
They told me leadtime for new orders is 50 weeks at the moment.

kominak

Re: HAUFE BV107 original Neumann KM84 transformer GROUP BUY CLOSED!
« Reply #63 on: January 17, 2019, 02:52:30 PM »
Just trying my luck here, but if any of you guys decided you don't need 1-2 of these transformers, send me PM...

Martin

TwentyTrees

Re: HAUFE BV107 original Neumann KM84 transformer GROUP BUY CLOSED!
« Reply #64 on: January 17, 2019, 05:03:30 PM »
Just trying my luck here, but if any of you guys decided you don't need 1-2 of these transformers, send me PM...

Martin

Heh! Ditto.  ;)

Jim50hertz

Re: HAUFE BV107 original Neumann KM84 transformer GROUP BUY CLOSED!
« Reply #65 on: January 22, 2019, 01:09:01 PM »
This is presumably now an available part from Haufe then Rainton? But a custom order?

If I manage to get in on Banzai’s bodies before it closes I would very much like the original trafos on board.

Any chance of another group buy?
"Nasty, talking to a slightly deaf journalist, had claimed only that the Rutles were bigger than Rod."

duantro

Re: HAUFE BV107 original Neumann KM84 transformer GROUP BUY CLOSED!
« Reply #66 on: January 31, 2019, 12:09:20 AM »
I’d be in on a pair of these if available.

Avgatzeblouz

Re: HAUFE BV107 original Neumann KM84 transformer GROUP BUY CLOSED!
« Reply #67 on: January 31, 2019, 12:05:26 PM »
I’d be in on a pair of these if available.
[/quote

Me too.]

iturnknobs

Re: HAUFE BV107 original Neumann KM84 transformer GROUP BUY CLOSED!
« Reply #68 on: February 09, 2019, 06:24:59 PM »
So guys, I can confirm that the Haufe fits Banzai's PCB.
The only thing is, that you have to extend the transformer cables, cause they are really short.
Put everything together 10 minutes ago and it works perfect.
Was to lazy to bias the fet right now, but will it do another day.
Tomorrow I can test it together with the cm5722 transformer.

Could you provide any info for wiring this trafo to KM84 circuit? Mine seems to test properly except I cannot seem to come up with a 200 ohm secondary impedance, regardless of my configuration.

Re: HAUFE BV107 original Neumann KM84 transformer GROUP BUY CLOSED!
« Reply #69 on: February 16, 2019, 10:41:33 AM »
Just a warning: on one of my group buy BV107's, a couple of extremely thin lamination shims fell out of the stack on one side; also one of the end U-shaped laminations moved a little bit.  I replaced the shims and pushed the U back into place and everything looked perfect.  Then I called my friend--former chief engineer for Jensen Transformer.  He suggested putting clear nail polish on them so that "capillary action" (a phrase he used several times) would wick little of the polish in between the edges of the laminations and glue the whole stack together. 

The only polish I could find on the shelf was a bit thick; using internet advice, I thinned it down a bit (a couple of drops of isopropyl alcohol in maybe 8 drops of polish) and painted it on with the brush from the nail polish.  Work quickly--mine seemed to be fully dry in just 2-4 minutes.  If I had it to do again, I might make the polish even a bit thinner and put a bit more on the laminations (for better "capillary action"). 


iturnknobs

Re: HAUFE BV107 original Neumann KM84 transformer GROUP BUY CLOSED!
« Reply #70 on: February 16, 2019, 10:49:02 AM »
I just had the same issue occur, literally 4 minutes ago. I think it may benefit us all to use clear nail polish around the plates before assembly.

TillM

Re: HAUFE BV107 original Neumann KM84 transformer GROUP BUY CLOSED!
« Reply #71 on: February 22, 2019, 11:14:49 AM »
at one of mine BV107, the black wire fall out the lamination, when I soldered it to the pad.
Really really s****y !
Write Haufe and hope, that I can fix the problem.
The black wire should be ground, any ideas how I can fix it?

volker

Re: HAUFE BV107 original Neumann KM84 transformer GROUP BUY CLOSED!
« Reply #72 on: February 22, 2019, 03:23:10 PM »
If the wire colors are identical to the old transformers, black is the beginning of the winding. So I wouldn't get my hopes up for an easy fix... Post a photo?

Winetree

Re: HAUFE BV107 original Neumann KM84 transformer GROUP BUY CLOSED!
« Reply #73 on: February 22, 2019, 04:21:39 PM »
I had the white/black wire pull out when trying to solder the 2 whites together.
The end of the white wire was tinned but didn't look like it was soldered to anything inside.
Can this be fixed.
Having the same lamination problems. Thanks for solution.

TillM

Re: HAUFE BV107 original Neumann KM84 transformer GROUP BUY CLOSED!
« Reply #74 on: February 22, 2019, 08:48:14 PM »
So here’s a photo.
I can’t not measure any resistance.
The other coil has 65ohm resistance.
Well, I think it’s hardly to fix, maybe it’s impossible.
First time this ever happens to me and in the meanwhile I build tons of things.

volker

Re: HAUFE BV107 original Neumann KM84 transformer GROUP BUY CLOSED!
« Reply #75 on: February 23, 2019, 06:22:01 AM »
So the wire is still connected? If you can see part of the actual magnet wire, you could try to resolder. Otherwise there isn't much to be done other than rewind, since the black wire is the beginning of the wind.

TillM

Re: HAUFE BV107 original Neumann KM84 transformer GROUP BUY CLOSED!
« Reply #76 on: February 23, 2019, 07:14:56 AM »
Hi Volker,
No it’s not connected, I put it in for the photo.
Also talked to Moby meanwhile, the transformer is not repairable.
Just what you say, only a rewinding will rescue them.
I build so many mics and other stuff, this is the first time this happened to me.
As we say in Germany, I paid “Lehrgeld”.


 

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