Unbalanced Synth –> Guitar Pedals –> Active or Passive DI?

[Hugh Robjohns]

If you'd rather have the convenience of a rack mount 4-channel DI the Palmer Pan03 passive DI is good, but I've no idea how it will sound in your setup.

But as you like what the EMO does, I'd try and find a secondhand one of a similar vintage. I believe EMO originally used bespoke Sowter transformers, but changed to Carnhill transformers around 2017. I imagine the latter have very similar specs to the former, but they may well sound different when working into a very low impedance.

[skipper01]

Thanks yet again.
I found the receipt for my E525 and it was bought new back in 2008 so that’s interesting.
Yes I’ll firstly have a look around on the net to see if there’s anything older around.
Appreciate it’s impossible to say given my set up, ears and subjectivity but given the costs I may even consider a couple of the Orchid stereo micro DIs. Appreciate they are transformerless and active but they are capable of handling the higher line levels I understand. I’d imagine they will sound a bit different from passive units so may or may not be ‘better’.
The Palmer unit also looks convenient for sure.
As you said before the transformers in the E525 may be a factor in this colour change I like.

The agony of choice!
Thanks again for all the help which is appreciated and taking me forward for sure!

[skipper01]

Interestingly having taken the lid off the E525 there are x2 labelled as Carnhill 09A01 CH2511 45/07

Probably not gonna make that much differnece unless I can establish from canford what’s in a new one now of course

Cheers again

[Hugh Robjohns]

I may even consider a couple of the Orchid stereo micro DIs. Appreciate they are transformerless and active but they are capable of handling the higher line levels I understand. I’d imagine they will sound a bit different from passive units so may or may not be ‘better’.

They are truely excellent, but won't introduce any of the transformer character you're enjoying with the passive EMO. You will still have the character of the Apollo Unison processing, of course.
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[Hugh Robjohns]

Interestingly having taken the lid off the E525 there are x2 labelled as Carnhill 09A01 CH2511 45/07

Interesting... and that's 2008?

I have eight EMO mic splitters, some with Sowter and some with Carnhill... and I've not noticed any audible difference between them!

[skipper01]

That’s great and very helpful/reassuring to hear thanks.
Yes 100% definitely a purchase in June 2008 as I had kept the receipt.
I’ve taken a punt on a pair (x2 being sold together) of e520s from eBay.
Same box type/colour and spec obviously as the e525 I have, a bit beaten up cosmetically so obviously older but date unknown.
I can only hope all working together they afford a tolerance that affords my use.
If not, I’ll think again with what I discover!
It will be interesting to see what transformers are in these too!

[skipper01]

I received the x2 E520s and tested for my application.
They are clearly old and seen some action for sure!
They sound the same to me compared against each other.
I can hear a slight difference in comparison as a pair against the E525 stereo but its slight.
The only thing that is weird is one of the E520s doesn't have the -20db level drop when connecting into its Line input. Plugging into the Line input on it produces the exact same signal level as per the instrument input.
Moreover the speaker inputs seem to have just a -20db drop.

The other E520 does the exact same levels as per the E525 and is correct.

All levels match up exactly when using all Instrument inputs though.

Basically for the application im plugging in a Novation Summit with a master level at 12 o clock and to date been using the Instrument inputs.
The Line inputs (when working) afford a higher headroom and have a differing (lower) input impedance apparently.
These require more gain if used obviously.

I'm not sure what to do as its a bit weird.
I've noticed on my E525 apart from the top of the casing its nion impossible to take the thing apart to reveal the underside of the PCB - its almost like the sockets are added when inside the box?!?

Alternatively im wonder whether to just run with the Instrument inputs throughout although technically i guess i should be plugging into the Line inputs....?

[Hugh Robjohns]

The only thing that is weird is one of the E520s doesn't have the -20db level drop when connecting into its Line input. Plugging into the Line input on it produces the exact same signal level as per the instrument input.
Moreover the speaker inputs seem to have just a -20db drop.

Sounds like the shunt resistor has fried or there's a dry joint. Should be trivial to find and fix, especially as you have a second unit for compative measurements.

The Line inputs (when working) afford a higher headroom and have a differing (lower) input impedance apparently.

Yes... the pad in front of the transformer presents a different input impedance.

I'm not sure what to do as its a bit weird.

Find and fix the pad resistor...

I've noticed on my E525 apart from the top of the casing its nion impossible to take the thing apart to reveal the underside of the PCB - its almost like the sockets are added when inside the box?!?

I believe the sockets are fitted in the box, then the PCB is dropped onto their pins... so removal requires desoldering the pins on the sockets on one side.

You might be able to spot (and fix) a dry joint or spy evidence of a fried resistor (scorching) from the trackside.

If desoldering the sockets is not something you feel comfortable tackling, give Canford Audio Support a call. I'm sure they'll fix it for you for a fair cost.

Alternatively im wonder whether to just run with the Instrument inputs throughout although technically i guess i should be plugging into the Line inputs....?

Sure, you'll just get a little more transformer saturation... and since that's what you bought them for anyway it might not be a bad thing!

[skipper01]

Thanks so much for this further info Hugh - I'll have a go at mending myself then!
All works well though aside

Cheers again!

[mwtzzz]

The downside was the increased level of noise/hiss which i guess is due in part to the extra circuitry and reduction in level from the DI box (-20db)

Get a better quality DI box. For example Radial.

Turn up the volume on your hardware synth to 80%, plug the 1/4" mono out from the synth to the DI box, plug the XLR from the DI to the mic preamp on your mixer, turn up the gain until it registers a level signal, then turn down the fader to whatever level you want.

The better the quality of your equipment (Radial, Mackie, Allen and Heath), the better the results.