exxos's Atari, Amiga & retro forum

OK, installing and will share results without DFB1X at first.
Is the FPU mod (100pF) needed for v3? I have it from before.

whomper wrote: 15 Sep 2025 15:12 Is the FPU mod (100pF) needed for v3? I have it from before.

The 100pF wasn't a part of the V3. So probably should be removed to keep things simple for now.

Installed V3 clock patch with Delay On (delay off I get audio crackles in stock Falcon).

A few test results after installing clock V3 patch:

Scenario 1 - Stock Falcon w/ V3 clock patch
Cubase Audio & DMA test app - Working good. No crackles and no digital noise

Scenario 2 - DFB1X w/ V3 clock patch
Cubase audio - Digital noise after a few minutes of playing. I'm working at 44.1KHz in Cubase and the effect is like reduced bit size of the audio. I have linked a video that shows a similar audio behavior that I've recorded with a different clock patch DFB1X and Cubase
DMA test app - All good, green
If I bridge the DISABLE pins on DFB1X, I essentially get scenario 1 working.

The above is similar behavior to the classic clock patch behavior I had earlier, meaning does not work with DFB1X but does Stock Falcon mode.

Also, when operating DFB1X and Cubase, I do not see Led D3 (Green) light up at all although I would expect it to as Cubase uses the DSP.

In summary, clock V3 works great in stock Falcon but Cubase audio and DFB1X do not work together. Is it something with how Cubase works?

Thanks for the tests.

Does cubase need hardware to work? I'm wondering if I can run it here to test? It seems to circle DSP and we need to figure out what is responsible for the odd behaviour. I'm not sure this is even a typical clock patch problem

But also odd if it only works with delay on.. That delays SDMA and DSP... So maybe that's a clue..

So v3 works better than v4? Likely because of the extra delay..

EDIT
There's 2 delay settings on the V3.. What do you have it set at?

exxos wrote: 17 Sep 2025 18:10 Does cubase need hardware to work?

I'm out at the moment but pretty sure Zippy and T0ri worked on removing the dongle checks from Cubase Audio Falcon 2.06 in the last year.

viking272 wrote: 17 Sep 2025 19:35 I'm out at the moment but pretty sure Zippy and T0ri worked on removing the dongle checks from Cubase Audio Falcon 2.06 in the last year.

That be cool. If I can replicate @whomper issues then I can look into it more.

Again I think @stephen_usher had some related issues but i forget the details now.

Maybe even @Badwolf could do tests as well if he can monitor the DFB1 with his LA.

Obviously the SDMA DSP tests are not showing up this particular fault. If delaying the SDMA clock helps, it suggests some sort of timing issue or bus conflict somewhere.

If @whomper can say if hes tried the extra delay jumper, it adds more delay to the SDMA clock. It may give more clues.

whomper wrote: 17 Sep 2025 16:56 Installed V3 clock patch with Delay On (delay off I get audio crackles in stock Falcon).

I missed this before.. Delay off on stock falcon and sdma issues again..

DELAY OFF = 7ns default delay of the IC. Recommended configuration for stock machines.
DELAY ON = 14ns (2 Gate delay). - For experimenters only.
EX-DELAY = 24ns total delay (14ns + 10ns extra)

So why the heck does the SDMA need a delayed clock even on a stock falcon...

Actually it's not that simple as I think V3 used a inverter, so 62ns delay plus maybe 24ns. Technically the SDMA clock could be taken as the clock has 85ns delay, or about 40ns clock advance.. Hmm..

Maybe it's because the DSP is on its own clock and its causing random timing delays to the SDMA, which is on a fixed clock bus.. :shrug:

@exxos - I should be able to dig out a pukka Cubase dongle; I think I have both black (v2?) & red (v3/Audio) so you might then be able to try the original s/w.

Just let me know if that would help and I can brign them with my Falcon to CL4...

JezC wrote: 17 Sep 2025 21:00 @exxos - I should be able to dig out a pukka Cubase dongle; I think I have both black (v2?) & red (v3/Audio) so you might then be able to try the original s/w. Just let me know if that would help and I can brign them with my Falcon to CL4...

Thanks it may help.. But if there's a version which doesn't need the dongle, then I can give that a try first anyway.

So the SDMA actually has the 32MHz DSP clock going to it anyway.. So maybe its not so out of sync after all..


Though it may be worth adding something like 470R termination on the clock just as something simple to rule out. The clock was pretty bad when you scoped it originally @whomper ..

See back to this post..

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