Ibox Ibox Ibox.

Hookin up those Audio Boxes without gettin yourself Perplexed.
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ZEDLR
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Ibox Ibox Ibox.

Post by ZEDLR »

I'm often surprised at what isn't known amoung the amateur community about the "Murph Box" i'd like to add my 2cts as well, It Works...
and is Very Relative in the audio chain... I've talked to Julius W2IHY at length different times down through the years and i really enjoy his savy and building his Kits, They Do Work...very well...especially when operating on limited budgets...

http://w2ihy.com/ibox.asp

Get one "Build It" save the Expense and the RF/AC Hum Headaches....
BEER...........
KA3ZedLR.

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Jensen Jensen Jensen

Post by Voodoo Guru »

Howdy ZedLR!!
Welcome to the Voodoo Forum.
Glad to have you aboard.

Yes, we have used the I-box on several applications here.
But it was usually just for testing or temporary lash ups.
If it is going to be a permanent application, We always install one of the Jensen Audio Transformers.
It has superior 60cps Hum rejection, RFI shielding, and Frequency Response.
Don't get us wrong, The I-Box is a good unit.
But the Purists will usually go for the Jensen for isolation.
Take Care,
Last edited by Voodoo Guru on Fri Sep 18, 2009 2:44 pm, edited 2 times in total.
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ZEDLR
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Post by ZEDLR »

FB, and i'm glad you have experience with the circuit, of course it's not New, But, tried and true, and it's nice that someone has taken the time to package it for market, kudoos to Julius for providing an affordable solution in kit form that an aspiring audio enthusiast can build.

The variable attenuation is a big plus and the Break in the chain is key, I have modified a few of his circuit with differing tranny's and done some testing and for the most part i find his choice "Not To Shabby" really..

I have built up several audio chains trying Beheringer and others and still whether one chooses mike Feed or Balanced Mod Tap, that little box is handy for accomplishing keying tasks, audio break, attenuation, all in a neat little package.

Plug and Play....... I do like this Future we have the technology is just wonderful...
BEER...........
KA3ZedLR.

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Post by Voodoo Guru »

Yea, we must commend Julius for that item.
You are correct about the versatility it has.
It is great for experimenting and also troubleshooting RFI/Hum problems.
The only problem We have with it is the Telephone Modem Transformer that they use in it.
Think it is a Stancor TTCP2 or something like that.
It probably has the best frequency response of any of the telephone modem transformers out there, but.....
It is limited in the Low Frequency area.
It will pass the High Frequencies just fine, but it has a pretty bad roll off below about 60cps.
This is due to the design of course, there are not to many modems or telephones that require this.
The Jensen will go down to 20cps easily.
Now there are not allot of people out there that have a low frequency fundamental that low, but we are out there!
Another thing is that we do not like anything to be obstructed in passing low frequencies, you loose some of the resonance and richness.
Sure our fundamental is around 65cps, but there are allot of sub harmonix and energy even below this center frequency.
If the roll off is below that, then this is either lost or attenuated.
The other thing is that the Stancor is kind of ripply through the frequency spectrum. This can color the audio slightly.
The Jensen is ruler flat from 20cps to 20kc.
This is of course from our experience and is our opinion.
The Jensen Transformer also has a 120db rejection for common mode frequency rejection at 60cps....AKA - 60 cycle HUM.
It also has a 30db magnetic shield around it.
So all in all it is very much worth its price of 70 bucks.
We use them allot here.
It would be interesting to see how one could retrofit it to the I-box to combine the superior Jensen transformer performance with the portability and convenience of the I-box functions.......
hmmmmmmm.......
Sounds like a future project is developing.
Take Care,
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SMC Productions
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Post by SMC Productions »

wz5q wrote: It would be interesting to see how one could retrofit it to the I-box to combine the superior Jensen transformer performance with the portability and convenience of the I-box functions.......
hmmmmmmm.......
Sounds like a future project is developing.
Take Care,
Let me know, when you do that! :D
Calcitra Clunis
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On the List!!

Post by Voodoo Guru »

OK, Scot...
I put it on 'THE LIST'!!
hahahahahahahahahahah
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Re: On the List!!

Post by SMC Productions »

wz5q wrote:OK, Scot...
I put it on 'THE LIST'!!
hahahahahahahahahahah
No problem....just move it to the #1 spot...and I'll graciously volunteer to beta test it for you...

:P
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Post by !KANT »

That should be a relatively easy to moderate level of building projects for anyone...LOL!!!

I popped one of my Jensen transformers into the Behringer MX-882 and the other into a plastic project box. The JT-DB-E is passive [basic I/O], so no connections to the '882 except for the case to case ground--only did it since I did NOT have an extra project box around. **I know, it was a cheap-cheap-scrouge-cheap moment for me.... :oops: **

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Post by Voodoo Guru »

**I know, it was a cheap-cheap-scrouge-cheap moment for me....**
We heard 'Thats what She said' about you!! :twisted:
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Post by !KANT »

wz5q wrote:
**I know, it was a cheap-cheap-scrouge-cheap moment for me....**
We heard 'Thats what She said' about you!! :twisted:
Yea, she didn't like me SHARING MYSELF with others of her "kind"...oh well... :roll: **See my sig below...it says it ALL!!!! :lol:

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