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Old 17th February 2013, 03:32 AM   #2411
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Originally Posted by iancanada View Post
Thanks regal



Hi Fridrik

regal gives very good point.

Battery has some disadvantages:
1, Voltage is not stable, decreasing along the discharge, so there are always some sweet point, another secret.
2, Internal resistor is not keeping constant also
3. Sensitive to the load
4, Over-charge and over-discharge can damage the battery easily.

However the battery is the easiest way letting your touch the low noise power supply.

Ian
Quote:
Originally Posted by WhiteBull View Post
Ian and others hello,

some questions from me please, regarding TPS7A4700 low noise regulator board V2.5:

- from what I understand, you recommend the reg over a LiFePo4 battery for the Si570 clock board based on sonic attributes, correct? You've mentioned some disadvantages before, are there any advantages?
- I've recently connected two LiFePo4s instead of the AVCC tridents on Buffalo II and it was a great improvement. Would the regs be suited at this place as well then?
- how about a possible benefit of replacing the other two tridents: DVCC and Core 1.2V (in case it goes close enough to 1.2V)?

- You suggest battery-based 4V-6V DC power for the regs. Is 6V really the upper maximum input for the regs, because then 2S LiFePos and 6V gels fall out, only some NiMh combination would work, or maybe 4V gel?

Thanks,
Abel
Please see the battery disadvantages I listed above.

TPS7A4700 is very good based on my own experiment. I suggest you try both and select the one you like the most.

I use lifepo4 direct before, now I use 6V battery over TPS7A4700. They sound different in some way. But hard to tell which one is better.

I don't think big problem if you go a little bit over 6V. the limitation is the on board LDO. But have to be careful the surge and spike voltage.

Ian
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Last edited by iancanada; 17th February 2013 at 03:37 AM.
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Old 17th February 2013, 05:02 AM   #2412
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Thank you Ian,

but since I'm trying to figure my setup to be able to proceed with the groupbuy, I could use some more precise answers please!

- I've recently connected two LiFePo4s instead of the AVCC tridents on Buffalo II and it was a great improvement. Would the regs be suited at this place as well then?

- how about a possible benefit of replacing the other two tridents: DVCC and Core 1.2V (in case it goes close enough to 1.2V)? So are your regs suited for this positions and how low can we go with them? From the pdf it looks like it's 1.4V. Is that right, and if so, can the Buffalo take it?

- the input for the regs has to be always between 4-6V, regardless of the selected output voltage, or do we have a specified minimum dropping voltage related to the selected output voltage?

- Can we use 2 LiFePos or a 6V gel to power the regs, both around 6.8V charged? Or would a 4V gel fit better? Which 6V battery are you using?

If this works, I would exchange the tridents in order to get rid of the placid and use a battery instead.

Regards,
Abel
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Old 17th February 2013, 06:14 AM   #2413
qusp is offline qusp  Australia
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you will not get a precise answer to such a question, Ian deliberately left it up to you, the choice is yours. these areas of playing with clock and power supply are the only DIY left to do with this project, why do you want someone to take that decision away from you?

there are practical concerns and subjective ones, both of which he answered. the tps will not do 1.2v and no you cannot use 1.4v for the 1.2v ESS supplies

he told you hes using regulation after the batteries, he is using lifepo4. no the tps is not suitable for AVCC, its not low noise enough, AVCC voltage and noise directly effects Dac analogue output performance as well as voltage swing and offset. every single battery chemistry states the voltage at nominal voltage, so a 6v gel battery will be higher at full charge as well and lower later.
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Old 17th February 2013, 07:39 AM   #2414
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Thanks, I'm trying to get some technical information to make a setup and buying decision! Nothing subjective! My questions are as precise as I can put them!

Honestly I dislike your beating, I can live without it!

Since I've picked between the lines that the regs are technically not suited to replace the tridents, I'm still not clear about the input voltage for them. If Ian is using LiFePos as you say (Ian didn't by the way), then the regs are able to handle around 7V. Ian mentioned using a 6V battery, and that's what I would prefer too, but then charged when get close to 7V again.

So all I wanted to know with my last two questions is how we can use a 6V battery without hurting the reg.

Regards,
Abel
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Old 17th February 2013, 07:55 AM   #2415
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Originally Posted by WhiteBull View Post
Thank you Ian,

but since I'm trying to figure my setup to be able to proceed with the groupbuy, I could use some more precise answers please!
I do not think that more precise answers are possible, as Ian said, this is the area of personal preference, you'l have to try it and see for yourself.

Quote:
Originally Posted by WhiteBull View Post
- I've recently connected two LiFePo4s instead of the AVCC tridents on Buffalo II and it was a great improvement. Would the regs be suited at this place as well then?
Hey thanks for the tip, I'll try batteries in place of the trident regs one day later this year... I see that in the time I've been writing this that qusp has already replied, and he's right, so I'll leave this here.

Quote:
Originally Posted by WhiteBull View Post
- how about a possible benefit of replacing the other two tridents: DVCC and Core 1.2V (in case it goes close enough to 1.2V)? So are your regs suited for this positions and how low can we go with them? From the pdf it looks like it's 1.4V. Is that right, and if so, can the Buffalo take it?

- the input for the regs has to be always between 4-6V, regardless of the selected output voltage, or do we have a specified minimum dropping voltage related to the selected output voltage?

- Can we use 2 LiFePos or a 6V gel to power the regs, both around 6.8V charged? Or would a 4V gel fit better? Which 6V battery are you using?

If this works, I would exchange the tridents in order to get rid of the placid and use a battery instead.

Regards,
Abel
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Old 17th February 2013, 07:56 AM   #2416
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Quote:
Originally Posted by WhiteBull View Post
Thanks, I'm trying to get some technical information to make a setup and buying decision! Nothing subjective! My questions are as precise as I can put them!

Honestly I dislike your beating, I can live without it!

Since I've picked between the lines that the regs are technically not suited to replace the tridents, I'm still not clear about the input voltage for them. If Ian is using LiFePos as you say (Ian didn't by the way), then the regs are able to handle around 7V. Ian mentioned using a 6V battery, and that's what I would prefer too, but then charged when get close to 7V again.

So all I wanted to know with my last two questions is how we can use a 6V battery without hurting the reg.

Regards,
Abel
Hi Abel,

If it is the TPS7A47 LDO voltage regulator then 36 volt input and output +1.4 to +20.5 volt are the specs..

For a 3.3 volt output you can feed it with +4 (+3.6 <-> +3.7) to +36 volt.

Battery are not going to give you anything but trouble..

A capacitor multiplier in front of the regulator will give you ca. 40dB extra noise reduction and better performance than any battery..
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Old 17th February 2013, 08:00 AM   #2417
bkdog is offline bkdog  Australia
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Quote:
Originally Posted by WhiteBull View Post
Thanks, I'm trying to get some technical information to make a setup and buying decision! Nothing subjective! My questions are as precise as I can put them!

Honestly I dislike your beating, I can live without it!

Since I've picked between the lines that the regs are technically not suited to replace the tridents, I'm still not clear about the input voltage for them. If Ian is using LiFePos as you say (Ian didn't by the way), then the regs are able to handle around 7V. Ian mentioned using a 6V battery, and that's what I would prefer too, but then charged when get close to 7V again.

So all I wanted to know with my last two questions is how we can use a 6V battery without hurting the reg.

Regards,
Abel
You probably should ask these questions over at the TP thread, or on their forum. I imagine that Ian cannot really offer that sort of advise on another manufacturer's product...
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Old 17th February 2013, 08:03 AM   #2418
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whitebull, the reason I get frustrated, is because questions like input voltage are covered quite well repeatedly in this thread and hochopeper has taken a lot of time to collate the information in the wiki, yet we still get elementary questions posted in this thread. the dropout voltage limits are also covered here and clearly in the datasheet for the regulators.

Ian and others in this thread should not have to answer questions that could easily be answered if users took a few minutes to look some of this stuff up for themselves. the differences in applications for batteries are as varied as the different types of batteries and are also effected by factors such as your charge program. those questions are for you to answer. then youve also added in some questions about the application of the ESS dac, which has nothing to do with Ian.

Last edited by qusp; 17th February 2013 at 08:07 AM.
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Old 17th February 2013, 08:10 AM   #2419
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Quote:
Originally Posted by WhiteBull View Post
Since I've picked between the lines that the regs are technically not suited to replace the tridents
Quote:
Originally Posted by bkdog View Post
You probably should ask these questions over at the TP thread, or on their forum. I imagine that Ian cannot really offer that sort of advise on another manufacturer's product...
TPS7A47 with properly decoupling and a capacitor multiplier in front should beat tridents - and why ask questions where he most certain would get biased answers
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Old 17th February 2013, 08:12 AM   #2420
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Ray, its misleading to say you can realistically input +36v for a +1.4v output and you have not even covered load current. this application of the TPS reg does not have much copper for heatsink, its designed for a low dropout voltage at 100-150ma in this application. the TPS gets best performance with ~1V dropout to work with.

a cap multiplier will negate or complicate the use of the load sense function, load regulation and transient response suffers, so not sure of the improvement

the question was directly feeding the board with batteries, or regulate beforehand, therefore the dropout of the onboard regs was the dropout under discussion, not the dropout for the TPS7A4700

Last edited by qusp; 17th February 2013 at 08:19 AM.
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