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EQ573 Equaliser / Re: EQ573II - Lowband 70Hz - faint-to-no audio when selected

« on: August 30, 2022, 06:45:12 PM »

Hi JP - that recommendation worked. 
I couldn't tell which joint was not soldered properly enough, but that's besides the point.
Followed your guidance and reapplied solder-gun/resoldered/flux/cleaned and I am getting signal on 70Hz lowcut! 

I think I saw this in another post here when originally looking for an answer re: my issue, but there is some sort of "clicky" lag when switching bands on that one, only to come in later just fine.

tested today extensively and I'm getting good and consistent sound through the EQ.

Thanks again!!

2

EQ573 Equaliser / Re: EQ573II - Lowband 70Hz - faint-to-no audio when selected

« on: August 29, 2022, 04:30:11 PM »

Yes the bottom most knob...
I am hoping it's not the rotary switch albeit it had to be desoldered once already slowly and carefully but still took a while, since I initially put it in the wrong place when not paying attention.
So it very well could have been damaged but it works fine except for 70Hz.

I'll check those other things you mentioned below later today.
Pls let me know if there is anything else I should look into.

thx
tal 

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EQ573 Equaliser / EQ573II - Lowband 70Hz - faint-to-no audio when selected

« on: August 29, 2022, 07:13:21 AM »

Hi JP,

So I finished building my 2nd EQ573II now that I got the replacement rotary knobs (thanks for the quick shipment!). 

All seems to work fine EQ-wise (haven't fully tested with preamp just yet), but I am having an annoying issue with lowband knob - when selecting thge 70 Hz filter specifically, it quiets down to extremely low-volume to no audio at all when source is not very loud. 
All other bands/off seem to work fine. 
Same for other knobs/selectors.

I doublechecked all solder joints, in looking at the schematic I was trying to figure out the signal flow when 70Hz is selected but I got a bit lost.

What would cause this? Which component(s) and traces that specifically are related to 70Hz selection, should I check?

Thank you.

Tal

4

EQ573 Equaliser / 3 pin connector cable!!

« on: June 29, 2022, 09:38:24 PM »

Hi,

I've had a heck of a time trying to put together this cable, as embarrassing as that sounds. 
I've put together 10+ DIY units but stripping & terminating cables properly isn't my forte I guess.
And now I've damaged the crimps and shortened the cable a lot trying to cut-redo-cut-redo-cut-redo and it's still not even and the balancing wire always ends up too short or long.

Would any 3-pin female-to-female connector work if I went and bought one on Amazon or elsewhere? Or does it have to be shielded/balanced? 

Would something like this (little longer though) work? 

https://www.amazon.com/dp/B00O9Y8HYO?psc=1&ref=ppx_yo2ov_dt_b_product_details

5

TS500 Tape Simulator / Re: Unit gain & calibration issues

« on: June 23, 2022, 04:04:58 PM »

Not for this scenario but not sure I understand the relevance/question?

I literally ran the first test mentioned with both units out of 500.
Then I put them in (without XT) and placed them both in bypass with output/input same, to receive the results mentioned.

Let me know if you need to measure any TP's with the specific test conditions and flows and I can do so. 

Thanks

6

TS500 Tape Simulator / Re: Unit gain & calibration issues

« on: June 22, 2022, 05:41:13 PM »

The TS500 doesn't have a true bypass.
When in OFF position, the signal goes through the input transformer, R1, the output stage and the output transformer. So there are many possibilities of gain difference.
This doesn't explain the difference between out and in the lunchbox though.
How to you do the measurements when out of the lunchbox? Could the difference be caused by input or output loading?

Hi - I ran the measurements with the usual test oscillator in Logic Pro and checking voltages on XLR outputs.
Nothing changed in Logic or chassis in terms of settings/levels/gain/etc - I only literally paused test sound, turned off chasis, inserted TS500's, and restarted sound test.
Hope this answers your question.

7

TS500 Tape Simulator / Unit gain & calibration issues

« on: June 16, 2022, 11:09:28 PM »

(Copy/paste from email sent to JP for help and hoping to get response via here)

Hi JP,
 
I have the 2 of the TS500’s bought ~1.5 months apart.
 
I have not been able to get them both to behave the same in terms of output and VAC/db measures even with continuous recalibrations of both.
 
In short and before I dive into all the results and steps – the first question I need help answered is on the following test condition I did:
 

Conditions	Switch position		Output voltage (VAC)	Output voltage (VAC)
input signal = sine 1kHz, 1VAC	Units out of 500 Lunchbox		1.001	1.003
input signal = sine 1kHz, 1 VAC	Units installed in 500. TS500 is OFF	* Levels are ~-1.0db differenece without units being switched to ON	0.861	0.959

 
 
As you see, without any unit being installed in my 500 Rack (Cranborne 500ADAT slots 13 & 14 in this case), for the same Sine wave I get nearly identical output VAC and db in my DAW with a negligible difference on the right side.
However, where I am stomped is – even when the units are in OFF position, with DRIVE on 0 just in case (I know it’s not supposed to affect when in OFF), and OUTPUT on 10 – I am getting a large difference out of the box already between L & R units.
 
Need some guidance as to what would cause this as I thought these are “true bypass” and yet I am getting this difference. 
 
Thank you in advance.