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DI Dox vs Transformer Barrel Adaptors for modular synths ?
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Author DI Dox vs Transformer Barrel Adaptors for modular synths ?
lucringeisen
Hi !

just bought a dual radial JDI to plug my (high end, Cwejman) modular synth into my Studer 269 console. It cancels the hum like it should and thats basically all I need ( the console can handle all kind of levels coming in in a very wide range so the hum and noise cancelation is pretty much all I need).

But I need more channels, to work quadraphonic, and also to connect other gears (drum machines etc). The Radial DI box being a bit expensive and given the fact that the "hum" is what really concerns me here, would some high quality transformer barrels do the job as well ? if so which ones are the best ? the synth and the console are high end so I like to mention that sound quality is important to me here.

finally any thoughts on the Orchid 8 channels passive rack ? i read that Orchid is great but that tranformer-less passive devices are not recommendable ?

thanks a lot in advance for any help !
milkshake
For trafo's, stick to the 3 well known: Lundahl, Sowter and Jensen.

17dBu is needed for modular levels, I think.

Wide bandwidth trafo's that can handle that level are about €100 each.
BugBrand
From what little I know, DIs depend almost entirely on the quality of the transformer (well, and good hardware helps). Radials have a good rep for a reason, I'd imagine!

I haven't heard of high quality barrel adapters but I only ever saw the cheapy ones which must have small low-quality transformers in.

It is hard to tell what that Orchid 8 might contain - the description is pretty minimal, so hard to tell if it'd be good or just OK (you could email them).

I'd slightly wonder why hum was occurring - it might be a cabling issue which doesn't actually require a DI - and I always wonder whether DIs (which typically take line level down to mic) are necessary vs. a 1:1 ratio line matching transformer (if that's the right terminology).

Could search around Jensen transformers - they make the transformers that Radial use. Good stuff apparently and there are many documents on the site if you can DIY your own.

Edit - ^^good trafos mentioned by milkshake above, yes^^
Navs
BugBrand wrote:
... I'd slightly wonder why hum was occurring - it might be a cabling issue which doesn't actually require a DI - and I always wonder whether DIs (which typically take line level down to mic) are necessary vs. a 1:1 ratio line matching transformer (if that's the right terminology)...


I agree. Wouldn't it be better to fix your hum?

I have a Radial Pro D2, the dual DI, but haven't had to use it for the modular per se. Simple attenuation has always been enough to go to a mixer/audio interface.
lucringeisen
Navs wrote:
BugBrand wrote:
... I'd slightly wonder why hum was occurring - it might be a cabling issue which doesn't actually require a DI - and I always wonder whether DIs (which typically take line level down to mic) are necessary vs. a 1:1 ratio line matching transformer (if that's the right terminology)...


I agree. Wouldn't it be better to fix your hum?

I have a Radial Pro D2, the dual DI, but haven't had to use it for the modular per se. Simple attenuation has always been enough to go to a mixer/audio interface.


Probably ! so what are those boxes ? should I just search for "1:1 DI box" ? are you guys recommending one ? again, based on sound quality
lucringeisen
lucringeisen wrote:
Navs wrote:
BugBrand wrote:
... I'd slightly wonder why hum was occurring - it might be a cabling issue which doesn't actually require a DI - and I always wonder whether DIs (which typically take line level down to mic) are necessary vs. a 1:1 ratio line matching transformer (if that's the right terminology)...


I agree. Wouldn't it be better to fix your hum?

I have a Radial Pro D2, the dual DI, but haven't had to use it for the modular per se. Simple attenuation has always been enough to go to a mixer/audio interface.


Probably ! so what are those boxes ? should I just search for "1:1 DI box" ? are you guys recommending one ? again, based on sound quality


well "DI box" is probably not the right word here, but more "1:1 transformer" or something, right ?
lucringeisen
milkshake wrote:
For trafo's, stick to the 3 well known: Lundahl, Sowter and Jensen.

17dBu is needed for modular levels, I think.

Wide bandwidth trafo's that can handle that level are about €100 each.


The Radial has Jensen. Thanks for the info will check the dBu's
calaveras
Shure Barrel adapters are good. I've used those before.
I've also seen folks buy the raw transformers from Jensen, Sowter, Lundahl etc and just zip tie them to a rack panel, and terminate them appropriately.
This is kind of tedious and only saves you money if you are doing 4+ channels. It's much easier if one or both ends are going to a patch panel with IDC or punch down connectors.
I did something similar a while ago with some Tamura 1:1 transformers I pulled out of a broken PM1000 mixer.
flo
I can highly recommend the Radial Stagebug SB6 for 1:1 transformer action: http://www.radialeng.com/product/stagebug-sb6

Dual channel, fully balanced/unbalanced compatible, ground lift, phase inversion and pad options - I love it thumbs up SlayerBadger!

I echo the advice to look into the reason of the hum, though - especially if you are calling it a "high end modular" hihi

Cheers Guinness ftw!
lucringeisen
flo wrote:

I echo the advice to look into the reason of the hum, though - especially if you are calling it a "high end modular" hihi

Cheers Guinness ftw!



Thanks ! Ho yes, Cwejman !! though lately some digital bitbox modules and more came in the rack. any hint about where I should start please ? I admit this hum came pretty recently, I changed the JACK/XLR adapters on the console to higher quality ones, also tried different output cables for the synth (mini to big mono jacks), also tried to plug the console and the synth to the same spliter from the same power socket on the wall, not too sure where to go on ? thanks a lot !
lucringeisen
calaveras wrote:
Shure Barrel adapters are good. I've used those before.
I've also seen folks buy the raw transformers from Jensen, Sowter, Lundahl etc and just zip tie them to a rack panel, and terminate them appropriately.
This is kind of tedious and only saves you money if you are doing 4+ channels. It's much easier if one or both ends are going to a patch panel with IDC or punch down connectors.
I did something similar a while ago with some Tamura 1:1 transformers I pulled out of a broken PM1000 mixer.


Thanks !!!
dubonaire
lucringeisen wrote:
flo wrote:

I echo the advice to look into the reason of the hum, though - especially if you are calling it a "high end modular" hihi

Cheers Guinness ftw!



Thanks ! Ho yes, Cwejman !! though lately some digital bitbox modules and more came in the rack. any hint about where I should start please ? I admit this hum came pretty recently, I changed the JACK/XLR adapters on the console to higher quality ones, also tried different output cables for the synth (mini to big mono jacks), also tried to plug the console and the synth to the same spliter from the same power socket on the wall, not too sure where to go on ? thanks a lot !


It could be the digital modules. Try disconnecting them and see what happens.
lucringeisen
dubonaire wrote:
lucringeisen wrote:
flo wrote:

I echo the advice to look into the reason of the hum, though - especially if you are calling it a "high end modular" hihi

Cheers Guinness ftw!



Thanks ! Ho yes, Cwejman !! though lately some digital bitbox modules and more came in the rack. any hint about where I should start please ? I admit this hum came pretty recently, I changed the JACK/XLR adapters on the console to higher quality ones, also tried different output cables for the synth (mini to big mono jacks), also tried to plug the console and the synth to the same spliter from the same power socket on the wall, not too sure where to go on ? thanks a lot !


It could be the digital modules. Try disconnecting them and see what happens.


I just tried that, no success
BugBrand
Not really knowing the 269 (or internal designs) - what input are you going to? Is there 1/4" Line or XLR Mic? I'd imagine there are input transformers in there.

Does the Studer have a correct 3pin earthed power cable & used in a properly earthed wall plug?

What is powering the Euro/Cwejman? (PSU type)

You mention XLR/Jack adaptors and trying other cables. I would imagine that this could be the area of issue - eg. going from unbalanced 3.5mm on the euro to balanced on the Studer.

I would imagine either unbalanced 3.5mm to unbalanced 1/4".
Or.
A correctly made unbalanced to balanced cable - eg. cable 13 or 14 on the Rane Interconnect Page
lucringeisen
BugBrand wrote:
Not really knowing the 269 (or internal designs) - what input are you going to? Is there 1/4" Line or XLR Mic? I'd imagine there are input transformers in there.


XLR only

BugBrand wrote:
Does the Studer have a correct 3pin earthed power cable & used in a properly earthed wall plug?


Yes for the cbale. Good question for wall plug :( I would say yes but will somehow doblecheck

BugBrand wrote:
What is powering the Euro/Cwejman? (PSU type)


Doepfer "Low Cost Case" (bigger model)

BugBrand wrote:
You mention XLR/Jack adaptors and trying other cables. I would imagine that this could be the area of issue - eg. going from unbalanced 3.5mm on the euro to balanced on the Studer.


Yes. though actually the rest of the unbalanced stuff works well, also the synth wasn't that noisy a few months ago

BugBrand wrote:
I would imagine either unbalanced 3.5mm to unbalanced 1/4".
Or.
A correctly made unbalanced to balanced cable - eg. cable 13 or 14 on the Rane Interconnect Page


nice one thanks !! though this document describes this technic as "The Last Best Right Way To Do It, if transformer isolation is not an option". Interesting though. Are those custom cables easy to order or do you solder them yourself if needed ?
lucringeisen
No way, I just found out about those balancing output modules !! can't beleive I didn't know they exist

WMD:
https://www.schneidersladen.de/en/wmd-pro-output.html?fbclid=IwAR3hkNj diNd3JCYA4QlRaPo6qaxoYWjiNS3Ma7J8qHbGR7Qt8W4mJ9nXmbI

Intellijel:
https://www.schneidersladen.de/en/intellijel-designs-audio-io-1u.html


thoughts PLEASE !

If sound quality is what drives you, would you go for one of those modules or stick to the Jensen transformers ? BTW are those modules transformers based ???? I guess they aren't, right ?
BugBrand
I did find a 269 service manual and had a quick look - it looked like it had separate inputs for mic and line (guess they're both on XLR?) both of which go through input transformers - so I would think that adding another transformer would be overkill.

Can you try the Euro setup into some other sort of mixer - ie. trying to isolate the problem / check that particular set up?

Yes, you can get Euro balanced out (though they probably won't adhere to the AES-48 spec due to there being no separate chassis ground in euro systems -- you might look up Graham Hinton posts for further info). There are also a number of transformer balanced ones - Vermona do one, for example.

You'd have to get a tech to make up the cables in the Rane doc if you can't solder yourself.
Navs
Radial's cheaper DIs use their own Eclipse brand transformers. I tested these against their Jensen-based DIs and, while there was a tiny difference, for my usage, it wasn't enough to convince me to spend the extra money. We're talking about synths with high output levels.

In terms of 'sound', transformers distort the signal - I'm not talking about the aspect, perceived or otherwise, of imparting a 'warmth' etc., but in the sense that they fail to deliver the sound 1:1. There are holes in the sound, at different frequencies, even between the channels. I get my 'best' sound going direct into my RME Fireface 400 audio interface.

If this is the route you want to go, there are multichannel DIs you can get using Jensen, Sowter, Lundahl etc. transformers, or the cheaper ones you'll encounter on live stages, like Palmer and BSS. You can drive yourself mad, as I did, comparing or reading Gear Sluts threads lol But, I really think you should try to fix the hum; it shouldn't be there hmmm.....
lucringeisen
BugBrand wrote:
I did find a 269 service manual and had a quick look - it looked like it had separate inputs for mic and line (guess they're both on XLR?) both of which go through input transformers - so I would think that adding another transformer would be overkill.

Can you try the Euro setup into some other sort of mixer - ie. trying to isolate the problem / check that particular set up?

Yes, you can get Euro balanced out (though they probably won't adhere to the AES-48 spec due to there being no separate chassis ground in euro systems -- you might look up Graham Hinton posts for further info). There are also a number of transformer balanced ones - Vermona do one, for example.

You'd have to get a tech to make up the cables in the Rane doc if you can't solder yourself.


Thanks for your help ! will be able top try the synth on a Midas console early next month, will check for sure.

You are right about the euro outputs, trying them at the moment, they don't affect the noise at all. Do you think it is possible/easy to modify them to make them compatible with the AES-48 spec ? This documents clearly says there is a hierarchy, 1/ the best way, 2/ the not so best 3/ the worse, the best being to use only balanced lines so in this case it would be to use euro rack balanced out....

for now, the only thing that worked for me regarding the noise of the modular synth is the Radial JDI. when you wrote "overkill" are you talking in term of volume drop or sound quality due to the signal going through various transformers ? TBH I am enjoying being finally able to record the synth (and even drum machine) through the mic preamps of the studer and I like the sound

Then, I also isolated 2 other sources of hum, but they seem to be more some kind of mechanical hums (vibrations) that even transformers can't eliminate, one caused by the eventide H8000 and the other one by the Tascam DA-3000 master recorder. Such a shame to buy a high quality recorder to end up with such a strong noise that the recordings are not usable. and what to say about gears in the price range of the harmonizers :( (been reading about users modifying them to be able to use them)
lucringeisen
Finally, it seems there is also some power supply issue going on (I am using cheap multiple power sockets, can it be one of the problems cause ?). For ex. I just unplugged from power socket the ERM multiclock, and like half of the total hum went away (hum was happening even if multiclock was trund off). Then I plugged (always in power socket) the mod. synth in (turned ON), and big hum comes back, I unplugged it again, and plugged back the multiclock, no more noise... surviving here by connecting only and stictly the gears I am using at the right same moment, but starting to be scared a bit about my next gig early march
BugBrand
OK - you're gradually finding things out by doing the approach of building it up piece by piece, checking at each step.

By overkill I meant that if there are transformers on the inputs of the Studer then you shouldn't need another set for gavlanic isolation.

It would seem that neither the doepfer PSU nor the ERM (guessing) have a connection to mains earth so are likely floating with respect to the studer / mains earth.
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