EQN build thread

[peter purpose]

You've either done something wrong, or you've done something wrong then... cough.

 

[bobschwenkler]

Hey All, I just skimmed through the first couple pages and didn't see an answer, forgive me if it's been asked already: What's the cost for one of these units run in USD?

 

[jensenmann]

Regarding hum: is your 1084 placed near the PSU? If so move it to the slot farest from the PSU. Try to shield the inductors with some brass (iron! not aluminium, not copper).

 

[jandoste]

Regarding hum: is your 1084 placed near the PSU? If so move it to the slot farest from the PSU. Try to shield the inductors with some brass (iron! not aluminium, not copper).

Hi Jensen,
Yep, it is near the PSU... Will try it.
Thanks,

 

[bobschwenkler]

Is there a schematic for this unit?

 

[peter purpose]

There is.

 

[bobschwenkler]

Where can I find this schematic?

 

[peter purpose]

Page 6

 

[bobschwenkler]

Thanks! As a suggestion to help out other newcomers like me it would probably be helpful to have it in a more visible spot, like the first page of this thread or the EQN website.

 

[dmp]

So I've noticed both of my EQNs have a low frequency sputtering noise. With no signal, they both put out about -55 dB (into a +4db soundcard input). It sounds like wind on a microphone. Turning up the HPF stops it. Any ideas? Any else noticed this? I'm using them in a 51x rack.

 

[canidoit]

 

[dmp]

This is my understanding:
RV4 sets the level of the EQ. It's purpose is to match the signal level to unity.
So run a signal through the EQ in bypass and observe the level, then engage the EQ and match the level using the trimpot.

RV5 is adjusted to get symmetric clipping. If you cannot see the signal clipping on your scope, then your signal is not high enough. Since you are using a signal from a macbook pro it is not surprising that you cannot clip the EQN. You need a signal of several volts to get a Neve circuit to clip.

 

[onlymeeee]

Boost at around 1k or whatever with the eq .. that'll give you 18dB or whatever extra gain before the output stage

 

[canidoit]

This is my understanding:
RV4 sets the level of the EQ. It's purpose is to match the signal level to unity.
So run a signal through the EQ in bypass and observe the level, then engage the EQ and match the level using the trimpot.

RV5 is adjusted to get symmetric clipping. If you cannot see the signal clipping on your scope, then your signal is not high enough. Since you are using a signal from a macbook pro it is not surprising that you cannot clip the EQN. You need a signal of several volts to get a Neve circuit to clip.

Thanks DMP, I will try that on the RV4

 

[BrodieSound]

Hi,

Could anyone share the part numbers they used for R27 & R32? I have mouser part no.s 66-GS3T012J (R27) & GS3-100-47R0JLF (R32) but thy seem far too big to fit neatly on the board?

Thanks,

Steve

 

[peter purpose]

They are 0.5" pitch... so anything with a smaller body than that will do you.

 

[BrodieSound]

They are 0.5" pitch... so anything with a smaller body than that will do you.

Sorry, I'm pretty new to DIYing and lack knowledge (and confidence) when it comes to sourcing parts but I've found these, are they ok?

Thanks again,


71-CPF212R000FKE14
(http://uk.mouser.com/ProductDetail/Vishay/CPF212R000FKE14/?qs=nHuOPoDtCcQ0W7e%252bm%252bMk7g%3d%3d)

594-5083NW47R00J
(http://uk.mouser.com/ProductDetail/Vishay-BC-Components/PR02000204709JR500/?qs=sGAEpiMZZMu61qfTUdNhG%2f4r7Iw6CIkyujIHaiAeRPI%3d)

 

[peter purpose]

Both of those should do you, but if you're in the UK go to one of the UK distributors.
Farnell, RS and Rapid spring to mind.

 

[BrodieSound]

Calibrating RV5?
I've been trying to follow the calibration guide on the 'journey' thread but I don't seem to be able to make RV5 have any impact on the shape of the sine wave how ever far I turn it cw or ccw. Currently the sine wave is slightly blunt at the bottom when sending 1khz at 0dbu and if I try to boost the gain as suggested on the other thread it ceases to look anything like a symmetrical sine wave.

Any suggestions/guidance anyone?

Thanks,

Steve

 

[BrodieSound]

OK ignore that last post (oh you were anyway!) I'm continuing to troubleshoot and hope I'm making progress. No doubt I'll be back with some really rudimentary questions.