Hi all,
I recently found some Lithium Titanate (LTO) batteries on ebay and thinking that they can be used for 5 VDC DAC or ADC supplies I'd just like to mention it here.
The batteries nominally are 2.9 AH/2.4 VDC (3 AH) versions, however, their discharge curve voltages start around 2.5 to 2.7 volts. See e.g. here (larger capacity battery):
lithium & solar power LiFePO4 : Photo
According to a measurement the seller has emailed me these batteries may have an internal impedance as low as 1 milliohm (see first attached image). When discharged through a clamp at a 10A rate the combined impedance of the clamp/wires + battery is about 9 milliohms (second image & third image).
Additionally, to my knowledge the lifespan for LTO cells can be very long - many thousand charge/discharge cycles.
A link to the ebay ad is here:
Toshiba 2 4V 3Ah Lithium Titanate Li ion LTO Battery Cell 180 Amps Current | eBay
For a bit more information on these cells Toshiba lists some information on their webpages:
“ŒŽÅ‚Ì“ñŽŸ“d’r SCiB�b2.9AhƒZƒ‹
The European EV/GWL company also has posted some measurements on LTO cells (another brand though) which can be found here:
lithium & solar power LiFePO4
As far as I can see LTO cells can be charged as a normal Li-ion battery when observing their lower voltages.
FYI in case it may be of interest to others here ...
Cheers
Jesper
I recently found some Lithium Titanate (LTO) batteries on ebay and thinking that they can be used for 5 VDC DAC or ADC supplies I'd just like to mention it here.
The batteries nominally are 2.9 AH/2.4 VDC (3 AH) versions, however, their discharge curve voltages start around 2.5 to 2.7 volts. See e.g. here (larger capacity battery):
lithium & solar power LiFePO4 : Photo
According to a measurement the seller has emailed me these batteries may have an internal impedance as low as 1 milliohm (see first attached image). When discharged through a clamp at a 10A rate the combined impedance of the clamp/wires + battery is about 9 milliohms (second image & third image).
Additionally, to my knowledge the lifespan for LTO cells can be very long - many thousand charge/discharge cycles.
A link to the ebay ad is here:
Toshiba 2 4V 3Ah Lithium Titanate Li ion LTO Battery Cell 180 Amps Current | eBay
For a bit more information on these cells Toshiba lists some information on their webpages:
“ŒŽÅ‚Ì“ñŽŸ“d’r SCiB�b2.9AhƒZƒ‹
The European EV/GWL company also has posted some measurements on LTO cells (another brand though) which can be found here:
lithium & solar power LiFePO4
As far as I can see LTO cells can be charged as a normal Li-ion battery when observing their lower voltages.
FYI in case it may be of interest to others here ...
Cheers
Jesper
Attachments
nope each cell is rated for charging based on the expected life time.
there are so many Li chemistries and markets right now. The final charge voltage and DoD is key to reduce failures and each chemical additive affects this.
BTW a normal Li-ion is considered an 18650 cell /500 cycles 3.7V. ( 3.0-4.2 V ) from everything I can see these look very much different.
I reckon these are from aircraft batts leaving the marketplace for some reason or another?
i'd be concerned more with their history rather than some AC measurement
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Hi ... Hmmmm... I'm not really inclined to debate on the batteries as such - I'm thinking that those who find the batteries interesting may just see this thread.
@ infinia:
This is interesting .. I haven't noticed this when searching the internet .. Can I ask you to elaborate on what it may mean in practice? As far as I can see the LTOs are pretty rugged and may accept many different charging voltages ...
Best regards,
Jesper
@ infinia:
This is interesting .. I haven't noticed this when searching the internet .. Can I ask you to elaborate on what it may mean in practice? As far as I can see the LTOs are pretty rugged and may accept many different charging voltages ...
Best regards,
Jesper
cells are made for a purpose, those ones look to be made for high cycle count / long life as per the OEM designed them and based on charge / DoD profiles only they can provide. Much info on 18650 available > study Panasonic / Sanyo data sheets also Battery University website is good place to start too.. they have curves on cycle count vs charge capacity etc, 18650 is based on 500 cycles but can be much more if lower Vmax and DoD, E.g. Tesla Motors etc. oh temperature is a biggy too.
probably the best way to kill a cell is high voltage at high temp.
best cells are new ones from a reputable distributor, ebay is next to last from a junk yard in china
but there are reputable dealers in China
probably the best way to kill a cell is high voltage at high temp.
best cells are new ones from a reputable distributor, ebay is next to last from a junk yard in china
but there are reputable dealers in China
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thanks I looked at the Toshiba sales blurb I didn't see a data sheet
they look nice > super fast charge plus long life perhaps against the no-compact / weight eff. also 2 cells hold charged voltage to 5V fairly nicely without regulation.
BUT don't use a normal Li-ion charger it will destroy them if left on. Even a programmable hobby charger would be confused by this cell voltage.
note> best to calculate Whours AH will fool you due low voltages
latest Panasonic 18650 is 3.7V @ 3.20 Ah ~12Wh per single small cell
they look nice > super fast charge plus long life perhaps against the no-compact / weight eff. also 2 cells hold charged voltage to 5V fairly nicely without regulation.
BUT don't use a normal Li-ion charger it will destroy them if left on. Even a programmable hobby charger would be confused by this cell voltage.
note> best to calculate Whours AH will fool you due low voltages
latest Panasonic 18650 is 3.7V @ 3.20 Ah ~12Wh per single small cell
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Hi Eldam ... Pleased to "read your voice" again ;-) ...
I don't know which has the best ESR but the impedance of these cells is around 1 milliohm - also when measured dynamically. In either case my personal main interest in them is the voltage ... compared with LiFePOs they have a lower voltage and may directly be used with ADCs or DACs that require 5 VDC supply.
Cheers,
Jesper
I don't know which has the best ESR but the impedance of these cells is around 1 milliohm - also when measured dynamically. In either case my personal main interest in them is the voltage ... compared with LiFePOs they have a lower voltage and may directly be used with ADCs or DACs that require 5 VDC supply.
Cheers,
Jesper
I am reawakening this old thread because it seems to me that the LTO batteries have not gotten the attention from the audiophile community that they merit.
I have been exploring ways to enhance sound quality through better power and 2 LTO batteries in series provides the 5V that devices like my AD1865 DAC need.
My understanding is that LTO batteries also have a much lower ESR than even LifePo4 batteries. It makes me wonder if they could match or beat the SQ of Ultracapacitors (that I run in parallel with “Studer 900” power supplies for 5V, for instance, with a managed low-current charge-up setup).
…or if using LTO batteries in parallel with Ultracapacitors sounds best?
Some builds and ABX tests are in order. I have some LTO batteries on the way and plan to build a charge-balance management system with Arduino initially.
I would be happy to share what I learn if there is interest from others.
I have been exploring ways to enhance sound quality through better power and 2 LTO batteries in series provides the 5V that devices like my AD1865 DAC need.
My understanding is that LTO batteries also have a much lower ESR than even LifePo4 batteries. It makes me wonder if they could match or beat the SQ of Ultracapacitors (that I run in parallel with “Studer 900” power supplies for 5V, for instance, with a managed low-current charge-up setup).
…or if using LTO batteries in parallel with Ultracapacitors sounds best?
Some builds and ABX tests are in order. I have some LTO batteries on the way and plan to build a charge-balance management system with Arduino initially.
I would be happy to share what I learn if there is interest from others.
Hi JCMcNeil,
Sounds interesting what you are considering ... I am still using them in some circuitries (the Toshibas mentioned above), however, I do not have a clear impression of their sound imprint as of today. But given that their impedance is very low (to my memory around 1 mohm) I reckon they would interact "actively" with the other circuitry parts in the frequency range where this impedance is low.
I have listened to a couple of Ultra/supercapacitors (Maxwell 50F & 3F) and just from memory the Toshiba LTOs sound very dynamic whereas the Maxwells are a bit muted, darkish and shut-in sounding (sins of omission and not addition). But I'd like to emphasize that this was not a direct comparison - from memory.
On the very few occasions where I unwittingly have happened to short-circuit the LiTO's terminals the sparks have been of a considerable size - so my guess would be that they are quite capable in terms of dynamic power delivery (and a real low impedance).
Cheers,
Jesper
Sounds interesting what you are considering ... I am still using them in some circuitries (the Toshibas mentioned above), however, I do not have a clear impression of their sound imprint as of today. But given that their impedance is very low (to my memory around 1 mohm) I reckon they would interact "actively" with the other circuitry parts in the frequency range where this impedance is low.
I have listened to a couple of Ultra/supercapacitors (Maxwell 50F & 3F) and just from memory the Toshiba LTOs sound very dynamic whereas the Maxwells are a bit muted, darkish and shut-in sounding (sins of omission and not addition). But I'd like to emphasize that this was not a direct comparison - from memory.
On the very few occasions where I unwittingly have happened to short-circuit the LiTO's terminals the sparks have been of a considerable size - so my guess would be that they are quite capable in terms of dynamic power delivery (and a real low impedance).
Cheers,
Jesper
Hi Jesper,
Thanks for sharing …. Interesting.
How do you recharge your LTO’s?
I have some small 1.5ah LTO’s on hand I just tried on an AD1865 dac with favorable results but I have not yet done an ABX versus the Ultracap + Studer 900 power … waiting on some larger 3ah LTO’s on order from China.
I plan to build a relays board with a remote to switch power source … and that randomizes a different color LED assigned to each power source so I won’t know which is which until the test is complete.
cheers,
Chris
Thanks for sharing …. Interesting.
How do you recharge your LTO’s?
I have some small 1.5ah LTO’s on hand I just tried on an AD1865 dac with favorable results but I have not yet done an ABX versus the Ultracap + Studer 900 power … waiting on some larger 3ah LTO’s on order from China.
I plan to build a relays board with a remote to switch power source … and that randomizes a different color LED assigned to each power source so I won’t know which is which until the test is complete.
cheers,
Chris
Hi Chris,
Regarding using the batteries e.g. in a DAC I think that the low LiTO impedances may interact with other DAC decoupling capacitors and make notches or peaks in the DAC capacitor frequency-impedance curve - something which might influence an ABX test depending on the comparative impedance levels of the Ultracapacitors you are planning to compare with (you may already know about this of course ...).
BTW can I ask you which LTO cells you have bought? 3 AH sounds very useable ...
Cheers,
Jesper
Well, they are not permanently connected to a circuitry (as it sometimes happens my DAC today is a DDDAC variant which needs 8V & 3.3V/4V) so I just recharge them with a linear regulator. However, when I will be using them more permanently in a circuitry (ADC) I will be float charging them with a voltage that is sufficiently low (appr. corresponding to 80% SOC) so that they are not "stressed" - and when highest sound quality is needed I will switch off the regulator/charger so that the circuitry is only fed from the battery. IME it is quite challenging to design a charger that will give maybe <150 dB noise at low frequencies (and I think this is audible in a very good system when it comes to fine nuances of various kinds).
Regarding using the batteries e.g. in a DAC I think that the low LiTO impedances may interact with other DAC decoupling capacitors and make notches or peaks in the DAC capacitor frequency-impedance curve - something which might influence an ABX test depending on the comparative impedance levels of the Ultracapacitors you are planning to compare with (you may already know about this of course ...).
BTW can I ask you which LTO cells you have bought? 3 AH sounds very useable ...
Cheers,
Jesper
@tubo I will, in time.
@gentlevoice I just found the batteries I ordered are not listed on Amazon anymore, it seems, but they appear to be identical to these on eBay: I ordered them at a lower price, though.
I have read it is not optimum to float charge lithium-based batteries, although I suspect the LTOs may be more tolerant than other chemistries, if this is indeed the case.
I also share your concerns about isolating the charging circuitry from the audio circuits.
So, I plan to treat them similarly to how I've applied LifePo4 batteries: Use a small Arduino (Pro Mini in most cases) or ATTiny84/85 to manage relays to alternate a battery (or bank of batteries) between charging and load. These circuits may also involve voltage measurement (though I've learned the batteries last long enough that it works well enough to just alternate on time intervals) and, possibly, an additional circuit with a power resistor to limit current if they are in parallel with a supercapacitor (bank) so they can charge up the supercapacitors with reduced current until near target voltage. In those cases, I definitely measure voltage, usually with a "flying capacitor" method to isolate the circuitry from the audio.
Recharging the LifePo4 batteries has been relatively simple because there are cheap, readily available TP5000 units made specifically for that purpose that are optimized for the chemistry and switch from constant current to constant voltage at the right time.. as well as disconnecting when the battery is optimally charged.
I have yet to find anything similar for LTO batteries so have been researching more extensive, discrete BMS circuits in which I can alter the parameters from regular lithium or LifePo4 batteries to suit the LTO batteries. I have just begun that process and expect to start with a fairly complex solution I will be able to simplify as I learn what is important versus not.
Some of my circuits (R2R DAC chips, for instance) seem to favor being constantly on, so I will want to alternate banks of batteries or, possibly substitute another 5V power source while the battery is being charged and music is not playing. Since I use Volumio as a media player app, I've been able to use ESP8266 modules in place of Arduino when I want the system to respond to music being played or not as it can recognize Volumio play status over the network.
I'd be happy to share details as this comes together if there is community interest. I also realize Ian Canada offers very good LifePo4 solutions. At the time I started developing mine, I don't believe his offered a way to keep constant power and that has been important to me since clocks also seem to perform better when constantly powered. I also wanted to develop the code and circuits myself to learn my way around this stuff in case I saw any opportunities for innovation in battery and ultracapacitor/supercapacitor power solutions for high end audio.
Cheers
Chris
@gentlevoice I just found the batteries I ordered are not listed on Amazon anymore, it seems, but they appear to be identical to these on eBay: I ordered them at a lower price, though.
I have read it is not optimum to float charge lithium-based batteries, although I suspect the LTOs may be more tolerant than other chemistries, if this is indeed the case.
I also share your concerns about isolating the charging circuitry from the audio circuits.
So, I plan to treat them similarly to how I've applied LifePo4 batteries: Use a small Arduino (Pro Mini in most cases) or ATTiny84/85 to manage relays to alternate a battery (or bank of batteries) between charging and load. These circuits may also involve voltage measurement (though I've learned the batteries last long enough that it works well enough to just alternate on time intervals) and, possibly, an additional circuit with a power resistor to limit current if they are in parallel with a supercapacitor (bank) so they can charge up the supercapacitors with reduced current until near target voltage. In those cases, I definitely measure voltage, usually with a "flying capacitor" method to isolate the circuitry from the audio.
Recharging the LifePo4 batteries has been relatively simple because there are cheap, readily available TP5000 units made specifically for that purpose that are optimized for the chemistry and switch from constant current to constant voltage at the right time.. as well as disconnecting when the battery is optimally charged.
I have yet to find anything similar for LTO batteries so have been researching more extensive, discrete BMS circuits in which I can alter the parameters from regular lithium or LifePo4 batteries to suit the LTO batteries. I have just begun that process and expect to start with a fairly complex solution I will be able to simplify as I learn what is important versus not.
Some of my circuits (R2R DAC chips, for instance) seem to favor being constantly on, so I will want to alternate banks of batteries or, possibly substitute another 5V power source while the battery is being charged and music is not playing. Since I use Volumio as a media player app, I've been able to use ESP8266 modules in place of Arduino when I want the system to respond to music being played or not as it can recognize Volumio play status over the network.
I'd be happy to share details as this comes together if there is community interest. I also realize Ian Canada offers very good LifePo4 solutions. At the time I started developing mine, I don't believe his offered a way to keep constant power and that has been important to me since clocks also seem to perform better when constantly powered. I also wanted to develop the code and circuits myself to learn my way around this stuff in case I saw any opportunities for innovation in battery and ultracapacitor/supercapacitor power solutions for high end audio.
Cheers
Chris
Jesper,
On the issue you mentioned of a low-impedance battery interacting with decoupling capacitors ... do you think that is the dynamic referenced in this thread where LifePo4 battery-powered circuits are alleged by some to sound better without the normal decoupling capacitors by the chip?
I have so far gone the conservative route and kept the decoupling capacitors in place but maybe it's worth a blind A-B test to assess the difference... if it would be possible to even set it up properly, as "close to the chips" probably doesn't allow for running in and out a relay circuit.
Chris
On the issue you mentioned of a low-impedance battery interacting with decoupling capacitors ... do you think that is the dynamic referenced in this thread where LifePo4 battery-powered circuits are alleged by some to sound better without the normal decoupling capacitors by the chip?
I have so far gone the conservative route and kept the decoupling capacitors in place but maybe it's worth a blind A-B test to assess the difference... if it would be possible to even set it up properly, as "close to the chips" probably doesn't allow for running in and out a relay circuit.
Chris
Hi Chris,
Thanks for the link to the batteries, although I agree that they appear to be quite costly. To see if there were alternatives I did a quick search for similar batteries on aliexpress and it looks as if a similar (identical?) battery can be bought for around USD 6.5 ...
https://www.aliexpress.com/item/100...-1;DKK+131.17@salePrice;DKK;search-mainSearch
Regarding float charging Li-ion based batteries it is my understanding that it depends very much on how it is done. If one float charges a Li-ion battery at, say, 4.12 volts the battery is close to 100% SOC and is somehow permanently stressed. However, if one chooses a float voltage that does not stress the battery float charging will only limit battery life very little - if at all - since charging & discharging cycles also reduce the battery's life span. The potentially negative "side-effect" of float charging at a lower voltage is that the battery will not have full capacity and thus may be discharged for a shorter length of time.
Batteries basically are large capacitors with an "instant capacitor" portion comparable to a traditional capacitor (I have seen mentioned that this instant capacitor portion could have a magnitude corresponding to ~ 150.000 uF) and then a capacitance that is "slightly slower" because it is based on liquid chemistry. Additionally, most batteries are of a size where the inductances - due to size - are huge in a digital decoupling context: E.g. an A123 26650 battery would have an inductance of appr. 260 nH (wire from terminals down the sides meeting at the middle of the battery) - which means it will have virtually no decoupling effect at higher frequencies. Therefore, if one removes the normal decoupling capacitors from the circuitry it is almost imperative that it will be swamped with HF noise that will cross over to other circuitry sections and influence the sound of the overall circuitry. Now, I can imagine that in some cases this might sound "better", although I would not assume this to be the case in a system that is just reasonably revealing. One unique case where I reckon it might be positive though is if the removed decoupling capacitors were low quality capacitors - like e.g. low quality X7R ceramics or the like. Such capacitors may distort/be noisy - hugely.
To my knowledge something similar can be said about Ultracapacitors: typically very high capacitance at DC-near frequencies but it drops off rapidly at even slightly higher frequencies.
What I was referring to in my comment, however, was that if the impedance of the Ultracapacitor is much different from the impedance of the battery then it may shift the overall response of the decoupling capacitor network and this, I reckon, might in itself influence the sound. So if it were me I would keep impedances of the various cells to be compared at similar levels (e.g. max 20-30 mohms difference). Just my thoughts about this ...
I agree with having the circuitry powered up "always" from a sound quality perspective. Unfortunately not the most environmentally friendly approach in these greenhouse gas times but being a Dane we have good access to sustainable energy which is fine ...
I would be interested in seeing how you progress but will be following the thread "on the side" as time allows.
Have a good day ;-)
Jesper
Thanks for the link to the batteries, although I agree that they appear to be quite costly. To see if there were alternatives I did a quick search for similar batteries on aliexpress and it looks as if a similar (identical?) battery can be bought for around USD 6.5 ...
https://www.aliexpress.com/item/100...-1;DKK+131.17@salePrice;DKK;search-mainSearch
Regarding float charging Li-ion based batteries it is my understanding that it depends very much on how it is done. If one float charges a Li-ion battery at, say, 4.12 volts the battery is close to 100% SOC and is somehow permanently stressed. However, if one chooses a float voltage that does not stress the battery float charging will only limit battery life very little - if at all - since charging & discharging cycles also reduce the battery's life span. The potentially negative "side-effect" of float charging at a lower voltage is that the battery will not have full capacity and thus may be discharged for a shorter length of time.
Hmmm ... now we have never "met" here on diyaudio before so I do not know where you come from audio-wise, i.e. what your knowledge base is ... From what you write above I reckon you have some programming skills and also audio frequency analog electronics understanding, however, I cannot see if you are familiar with digital circuitry decoupling challenges .. ? So I'll reply as if you are not too familiar with this: As it is digital signals carry very high frequencies which typically cannot be decoupled (~shorted) to ground e.g. with typical larger size electrolytic capacitors. This is due to these capacitors' intrinsic inductance which becomes a resistor in series with the "capacitor portion" of the capacitor at higher frequencies. At higher frequencies typical e.g. 1000 uF capacitors have very little decoupling efficiency. Thus, in order to decouple higher frequencies (typically above a couple of MHz) smaller ceramic capacitors of 0.1 uF size are typically used. If these capacitors are removed the noise level on e.g. a DAC's PSU supply lines likely will go up quite a lot - noise which likely will somehow affect the DAC's performance also at audio frequencies.
Batteries basically are large capacitors with an "instant capacitor" portion comparable to a traditional capacitor (I have seen mentioned that this instant capacitor portion could have a magnitude corresponding to ~ 150.000 uF) and then a capacitance that is "slightly slower" because it is based on liquid chemistry. Additionally, most batteries are of a size where the inductances - due to size - are huge in a digital decoupling context: E.g. an A123 26650 battery would have an inductance of appr. 260 nH (wire from terminals down the sides meeting at the middle of the battery) - which means it will have virtually no decoupling effect at higher frequencies. Therefore, if one removes the normal decoupling capacitors from the circuitry it is almost imperative that it will be swamped with HF noise that will cross over to other circuitry sections and influence the sound of the overall circuitry. Now, I can imagine that in some cases this might sound "better", although I would not assume this to be the case in a system that is just reasonably revealing. One unique case where I reckon it might be positive though is if the removed decoupling capacitors were low quality capacitors - like e.g. low quality X7R ceramics or the like. Such capacitors may distort/be noisy - hugely.
To my knowledge something similar can be said about Ultracapacitors: typically very high capacitance at DC-near frequencies but it drops off rapidly at even slightly higher frequencies.
What I was referring to in my comment, however, was that if the impedance of the Ultracapacitor is much different from the impedance of the battery then it may shift the overall response of the decoupling capacitor network and this, I reckon, might in itself influence the sound. So if it were me I would keep impedances of the various cells to be compared at similar levels (e.g. max 20-30 mohms difference). Just my thoughts about this ...
I agree with having the circuitry powered up "always" from a sound quality perspective. Unfortunately not the most environmentally friendly approach in these greenhouse gas times but being a Dane we have good access to sustainable energy which is fine ...
I would be interested in seeing how you progress but will be following the thread "on the side" as time allows.
Have a good day ;-)
Jesper
Jesper-
Thanks for the thorough explanation. I have some understanding of digital circuits but certainly much deeper knowledge in software. I am learning quickly, though. Also, I really enjoy working with music oriented electronics in general, so would like to see how far I can take it. I admire people like the recently passed (RIP) Alexander Dumble, who, if you haven't heard of him, made some of the most exquisite sounding tube guitar amplifiers ... all by hand by himself. Hearing how his amps sound in the hands of Larry Carlton (Last Nite being a good example) and Robben Ford (Jing Chi Live is nice) is inspiring. I'm not them but I am at least a competent player when I practice/perform regularly and wonder if I can build a better sounding amp than, for example, a Fender Hot Rod such as I normally play through when I play electric.
But that's a whole other project, just sharing since you asked about my background (and yours?), back to the topic at hand:
It seems the ESR of LTO's is similar enough to that of the 310F-350F Maxwell Ultracaps I am currently using that the test should work in that respect.
It is likely the extra wiring needed to set up the test relays for quick ABX testing will introduce more resistance than that difference, which is an unfortunate extra variable I need to allow for in the testing.
That is especially relevant as I am becoming a big fan of getting this kind of passive power as close as possible to the load... to the point of designing new DAC boards that integrate Ultracapacitors in the board... along with the power resistors, and relays needed to ensure safe charge-up. That is, unless I discover that LTO batteries alone sound better than they do with Ultracapacitors in parallel. In that case, I hope to integrate the batteries and BMS in the board design to, again, shorten the power paths.
The ABX testing will have to lengthen those paths but I still think it can provide helpful insights. I wonder if the analog side of a DAC chip likes batteries better, for instance, as opposed to the analog side liking Ultracapacitors/Supercapacitors in parallel with a LRPS like the "Studer 900" boards I've built that usually seem to enhance the sound quality of a circuit.
Given self-fulfilling prophesy and all that, having something like the relay system I envision, with a remote and randomized "a" and "b" LED colors to identify which side - keeping which is which hidden until the end of the test - seems imperative.
And, then there is measurements. I have some decent ADC/DAC boxes I use for music production that I've used with REW to do things like adjust the trim pots of the AD1865 for lower distortion so I can at least do some basic objective tests ... though more sophisticated equipment would be helpful, of course.
Cheers
Chris
Thanks for the thorough explanation. I have some understanding of digital circuits but certainly much deeper knowledge in software. I am learning quickly, though. Also, I really enjoy working with music oriented electronics in general, so would like to see how far I can take it. I admire people like the recently passed (RIP) Alexander Dumble, who, if you haven't heard of him, made some of the most exquisite sounding tube guitar amplifiers ... all by hand by himself. Hearing how his amps sound in the hands of Larry Carlton (Last Nite being a good example) and Robben Ford (Jing Chi Live is nice) is inspiring. I'm not them but I am at least a competent player when I practice/perform regularly and wonder if I can build a better sounding amp than, for example, a Fender Hot Rod such as I normally play through when I play electric.
But that's a whole other project, just sharing since you asked about my background (and yours?), back to the topic at hand:
It seems the ESR of LTO's is similar enough to that of the 310F-350F Maxwell Ultracaps I am currently using that the test should work in that respect.
It is likely the extra wiring needed to set up the test relays for quick ABX testing will introduce more resistance than that difference, which is an unfortunate extra variable I need to allow for in the testing.
That is especially relevant as I am becoming a big fan of getting this kind of passive power as close as possible to the load... to the point of designing new DAC boards that integrate Ultracapacitors in the board... along with the power resistors, and relays needed to ensure safe charge-up. That is, unless I discover that LTO batteries alone sound better than they do with Ultracapacitors in parallel. In that case, I hope to integrate the batteries and BMS in the board design to, again, shorten the power paths.
The ABX testing will have to lengthen those paths but I still think it can provide helpful insights. I wonder if the analog side of a DAC chip likes batteries better, for instance, as opposed to the analog side liking Ultracapacitors/Supercapacitors in parallel with a LRPS like the "Studer 900" boards I've built that usually seem to enhance the sound quality of a circuit.
Given self-fulfilling prophesy and all that, having something like the relay system I envision, with a remote and randomized "a" and "b" LED colors to identify which side - keeping which is which hidden until the end of the test - seems imperative.
And, then there is measurements. I have some decent ADC/DAC boxes I use for music production that I've used with REW to do things like adjust the trim pots of the AD1865 for lower distortion so I can at least do some basic objective tests ... though more sophisticated equipment would be helpful, of course.
Cheers
Chris