freestompboxes.org

Hi,

I have a TC Nova Delay, I love it a lot, but one thing is bugging me, the amount of hiss that it inserts into my amp.
I use the pedal directly in front of the amp input and not in the loop.
I emailed TC Electronics and they told me that these pedals were designed for best performance in line levels. They also accept instrument levels, but their output are scaled for line levels. This means that going back to an instrument input, the signal will be hot, and the floor noise (from the guitar) is more audible.

Since the output impedance is as low as near 40 ohms, I recon that there's a lot of current going into the amp input thus injecting the noise.

Will a simple solution like a series resistor soldered into the cable-jack coming from the pedal limit the noise?

What are your thought about that?
Anyways, thanks a lot.
Kind regards,

Frank

BTW: I'm not sure if this is the right place to post this probem so it's ok if the moderators move it to another section of the forum.

Seljetnoma wrote: Since the output impedance is as low as near 40 ohms, I recon that there's a lot of current going into the amp input thus injecting the noise.

Will a simple solution like a series resistor soldered into the cable-jack coming from the pedal limit the noise?

No, there will be a very limited current because that output feedt into a high input impedance amplifier input. A resistor in between will only make your signal chain more vulnerable for noise.

It's a matter of determining where the noise comes from. From the guitar itself (stray pickup etc) or from the Nova. In case it's the nova perhaps something can be done in the form of mods with lower noise components (like low noise opamps). That is, if you're up to it.

Another option is putting it in the fx loop of your aplifier if it has one.

Today I opened my Nova Delay, just because I wanted to know what makes it tick.
Conclusion: Pretty sturdy build quality inside. Based on the Freescale DSP56362 DSP.

Pictures:


Without the pretty heavy sidepanels.


Pins for debugging?


A lot of shift registers.


See the atmel chip on the right?


Bottom print with the DSP chip and ram chip(s).


Chip in the bottom right says ND-1 V01.03 on the label, maybe firmware version.

This may interest you:

viewtopic.php?f=11&t=13652

And there boys and girls is a fine example of why we don't bother trying to clone a digital pedal such as these. but thanks for pics regardless

Just had one in that was not working.

With the PSU the unit powers up and just responds like it should, still, no output

The input was OK; on all lines perfect sound
On the output no sound; probed and checked with an scope and the signal dissapears just before the output jack

The outputs are wired up with an opamp that is buffering, put through a 1k resistor (SMD) and through a ferrite coil then fed into the output. The signal disappeared just after the 1k resistor. Flipped the board and discovered per output 2 transistors that, when activated, pulled the signal down to ground (guess for the panning delays). Q2 and Q4 turned out to be bad and grounded the output signal.

Only markings on the transistors: XL21; no idea what kind of transistors these are. All I could get from the units on the board is that they are NPN transistors, SOT23, with an Hfe of around 600.

Replaced Q2 and Q4 with new 2SC1815 (had no SMD laying around and the 1815 fit the SOT23 layout perfectly) and now the unit functions perfect again!

I got 1 unit send in for FREEZED switch for ON/OFF and PRESET.
ON-OFF switch is like always on. Cannot disengaged.
PRESET switch is like being always PRESSED AND HOLD but nothing change. No response to any further pressing.
Was told it started to behave that way after TAP/PRESET external switch mod.

Any clue where should i start checking?