How to disable the display and related power supply

[P Floding]

As sound quality have improved from the SB3 due to all sorts of changes I can now hear more clearly an improvement in performance when the battery supply goes low and the SB3's display stops working. (This is using the SB3 with SPDIF into a TacT)

I have heard this effect before but put it down to possibly imagining things. (Basically I found that sound was always very good just before the SB3 cut out due to low voltage.) But now the effect can be heard much clearer.

The effect is there even if the display has been turned off, so I assume it is the display's power supply that needs disabling. It cold be something else running off this supply, or something controling the supply/display that cuts out.

BTW, analogue out stops working before this happens, but digital out keeps going.

Oh, and increasing voltage again to the SB3 while it is running does not bring back the display to life. Power cycling is required. Not sure why.

[P Floding]

Well, I installed a switch in the power regulator box so I can now get the low voltage at any time. I need to confirm the findings before starting to modify the SB3..

I noticed on my bench supply that when the voltage goes down to 3.6V and the display cuts out (and analogue out too, the D/A probably), the current drain reduces by half down to 0.5A or so.

[P Floding]

I can crank the volume now (daytime now), and it sounds absolutely superb!

OK, now when I know what CD can do the question becomes: Look for jitter-imune DAC or persist with the TacT and modify the SB3 (or purchase the Transporter and hope it's this good). (Why, oh why, can't the TacT be jitter immune if the Benchmark can (apparently)?)

I guess tweaking will be cheap (barring incidents..)

[Phil Leigh]

I can crank the volume now (daytime now), and it sounds absolutely superb!

OK, now when I know what CD can do the question becomes: Look for jitter-imune DAC or persist with the TacT and modify the SB3 (or purchase the Transporter and hope it's this good). (Why, oh why, can't the TacT be jitter immune if the Benchmark can (apparently)?)

I guess tweaking will be cheap (barring incidents..)

PF - are you using the DACS in the TACT? (I can't remember). I found that I go a much better result by taking the digital output from the TACT into external Dac's.
Regards
Phil

[P Floding]

PF - are you using the DACS in the TACT? (I can't remember). I found that I go a much better result by taking the digital output from the TACT into external Dac's.
Regards
Phil

Thanks for the tip!
That is exactly what I'm planning to do ASAP. I'm using the internal DAC now. Only problem is which external reasonably priced DAC to use. I'm leaning towards getting a PCM1704-based one, such as the Lite DAC-38. (Cheap is good, in case I'm not happy. Also, if it's cheap it is easy to dig in and modify.)

[Phil Leigh]

Thanks for the tip!
That is exactly what I'm planning to do ASAP. I'm using the internal DAC now. Only problem is which external reasonably priced DAC to use. I'm leaning towards getting a PCM1704-based one, such as the Lite DAC-38. (Cheap is good, in case I'm not happy. Also, if it's cheap it is easy to dig in and modify.)

I'm using the Musical Fidelity x-dacv3 but with Altmann technology on the input. You might want to try the Altmann Dacs - My guess is you will like them - anyway it is a no risk money back option!
Cheers
Phil

[P Floding]

I'm using the Musical Fidelity x-dacv3 but with Altmann technology on the input. You might want to try the Altmann Dacs - My guess is you will like them - anyway it is a no risk money back option!
Cheers
Phil

Unfortunately those no-risk money back deals don't work too well if you are on a different continent. Also, one of those "no risk" deals charged not only delivery (fair enough) but a substantial restocking fee! (I know the Altmann is German, but the buy-to-test fenomenon seems to be North American to me.)

BTW, I had a look at the Altmann web site, and it seems he produces DACs with no digital domain filtering. Sort of a flat earth approach. Wonder how much HF noise makes it through?

[Skunk]

Well, I installed a switch in the power regulator box so I can now get the low voltage at any time. I need to confirm the findings before starting to modify the SB3..

Are the results in? I'd have given you another week if you'd have used three dots...

FWIW you can probably pull a cap out somewhere or cut a trace to disable the power to the display without under powering the entire circuit.

Also, if you want to keep the internal DAC/opamps, you could send battery power to their rail (since disabling the display cuts their power).

I've thought of this before, so hoped you'd actually go through with it. Good luck.

[P Floding]

Are the results in? I'd have given you another week if you'd have used three dots...

FWIW you can probably pull a cap out somewhere or cut a trace to disable the power to the display without under powering the entire circuit.

Also, if you want to keep the internal DAC/opamps, you could send battery power to their rail (since disabling the display cuts their power).

I've thought of this before, so hoped you'd actually go through with it. Good luck.

No, I need another SB as a reference before I start cutting. (And as a backup..)

I still use the voltage drop to get the wanted result.

However, I just installed my turntable again after having rested it for a couple years, and I might not care much about the sound quality from digital sources again... (three dots)

[Phil Leigh]

No, I need another SB as a reference before I start cutting. (And as a backup..)

I still use the voltage drop to get the wanted result.

However, I just installed my turntable again after having rested it for a couple years, and I might not care much about the sound quality from digital sources again... (three dots)

LOL - Have you been reading Hi-Fi World again, PF :o)

[P Floding]

LOL - Have you been reading Hi-Fi World again, PF :o)

I read it all the time!
No, I purchased a wall shelf on ebay so I can use the turntable without my son "investigating" the pickup!

There is something about the LP sound, even going through my TacT 2.2x. It just rocks a lot better.

[P Floding]

Installing the turntable again was the best thing I've done to the hifi for ages!

Listening to my wife's old Dire Straits "Communique" right now, and even though it sounds like a log fire in the background (or, perhaps, the house burning down -her LPs haven't been treated the audiophile way) it easily beats the cr*p out of the CD version. (God, what have they used to produce the 16/44 version?)

And that CD is one of my better sounding CDs...

It's nice to have something to work towards again for 16/44 playback quality.