Jay so in your opinion what should be the output of a pre-amp for a Tripath 2020 then ?
Milliwatts ?
I get that but I did say above I am bi amping to two tripaths and lots of pre amps output similar around 4W at 16 Ohms for example in stereo with just two 2 channels involved ?
Perhaps I should of made that clearer from the beginning but I see no Canon in the equation Kopi. But I am sure there are other issues as mentioned above like SNR ?
The issue of gain can always be aided by using a good stepped volume 42 steps and above if you get my drift ?
I think you need a cup of coffee dude and go swat some mosquitos or something ha that's funny !
As the name suggests I enjoy a laugh ��
Perhaps I should of made that clearer from the beginning but I see no Canon in the equation Kopi. But I am sure there are other issues as mentioned above like SNR ?
The issue of gain can always be aided by using a good stepped volume 42 steps and above if you get my drift ?
I think you need a cup of coffee dude and go swat some mosquitos or something ha that's funny !
As the name suggests I enjoy a laugh ��
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Anyone else got some thoughtful advise on the usability of of a 2020 to pre amp two bi amped 2020s is it feasible or not or anyone tried it ??
Any mods that might make it altogether more likely other than using cmoys in milliamps ?
Any ideas on how to limit the volume threshold to the desired 40-50% where there is no distortion but still maintain a good volume for a 2020 pre amp ?
Any mods that might make it altogether more likely other than using cmoys in milliamps ?
Any ideas on how to limit the volume threshold to the desired 40-50% where there is no distortion but still maintain a good volume for a 2020 pre amp ?
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Why not you try and let us know the outcome? Just create some smoke. Hey, we all learn from mistakes. I will sit back, sip my coffee and wait.
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Hello guys,
I am totally a noob in this area and have recently gotten interested into the Lepai LP2020A+ mini amp and want to mod it as a little side project of mine. I have read this entire thread (that took a while) and just wanted to verify some stuff before I go ahead with it.
I have received the Lepai LP-2020A+ with the latest board from Parts Express about two weeks back. Out of the box, the sound is clean and great, no hums, no buzzes, no distortions, no clipping even at 70% volume output. It comes bundled with a 12V 3A power supply, but I used a generic 12V, 5A PS and it works perfectly fine if not better.
Also please note that the part labels and numbers on the board have been changed (for e.g. the input coupling caps are now labelled as C21 and C22 instead of C30 and C31 in the earlier boards)
Here are a few of my questions....
1) Will this following Opamp from Mouser be a suitable replacement for the 4558 SMDs? Its LM4562MAX/NOPB. I ask this because in some other forums people have expressed concerns that many high quality opamps draw more current and hence require further modifications to the circuitry. I do not want to delve into all that and just want to do a simple swap of the 4558 with 4562. If such a direct swap is not possible can anyone please suggest other audio-grade opamps which can be directly swapped with the native 4558s without further modifications to the adjacent circuitry.
LM4562MAX/NOPB Texas Instruments | Mouser
2) The input coupling capacitors (C20 and C21 on my picture) - they are SMDs. I do not know what values they are of. However, from several forums the earlier Lepai boards used 3.3 uF OR 2.2 uF caps. I am opting for Panasonic metallized polypropylene caps - 2.2 uF, 5%, 450VDC as linked below. Will these be good replacements?
ECW-FE2W225JA Panasonic | Mouser
3) About the inductors - I am going with the following inductors:
Bourns 6100-100K-RC
Wurth electronics 744732100
Are these OK?
I will also upgrade the power cap, the output film caps and all the other electrolytic caps to either Panasonic or Nichicon caps of similar value.
Please comment on my selections and Thank you all for being a treasure trove of information.
I am totally a noob in this area and have recently gotten interested into the Lepai LP2020A+ mini amp and want to mod it as a little side project of mine. I have read this entire thread (that took a while) and just wanted to verify some stuff before I go ahead with it.
I have received the Lepai LP-2020A+ with the latest board from Parts Express about two weeks back. Out of the box, the sound is clean and great, no hums, no buzzes, no distortions, no clipping even at 70% volume output. It comes bundled with a 12V 3A power supply, but I used a generic 12V, 5A PS and it works perfectly fine if not better.
Also please note that the part labels and numbers on the board have been changed (for e.g. the input coupling caps are now labelled as C21 and C22 instead of C30 and C31 in the earlier boards)
Here are a few of my questions....
1) Will this following Opamp from Mouser be a suitable replacement for the 4558 SMDs? Its LM4562MAX/NOPB. I ask this because in some other forums people have expressed concerns that many high quality opamps draw more current and hence require further modifications to the circuitry. I do not want to delve into all that and just want to do a simple swap of the 4558 with 4562. If such a direct swap is not possible can anyone please suggest other audio-grade opamps which can be directly swapped with the native 4558s without further modifications to the adjacent circuitry.
LM4562MAX/NOPB Texas Instruments | Mouser
2) The input coupling capacitors (C20 and C21 on my picture) - they are SMDs. I do not know what values they are of. However, from several forums the earlier Lepai boards used 3.3 uF OR 2.2 uF caps. I am opting for Panasonic metallized polypropylene caps - 2.2 uF, 5%, 450VDC as linked below. Will these be good replacements?
ECW-FE2W225JA Panasonic | Mouser
3) About the inductors - I am going with the following inductors:
Bourns 6100-100K-RC
Wurth electronics 744732100
Are these OK?
I will also upgrade the power cap, the output film caps and all the other electrolytic caps to either Panasonic or Nichicon caps of similar value.
Please comment on my selections and Thank you all for being a treasure trove of information.
An externally hosted image should be here but it was not working when we last tested it.
I'll leave a few comments on my thoughts.
I have changed the inductors as in my previous posts and found that there was no audible change. Just an expense that didn't pay off. I would find 2.2uf caps with a much smaller voltage other than 450v. As for the opamp, your choice will work fine. I think you are wasting your time on changing that since this circuit is not high performance. Any noise figure that you may gain will be negated by the 2020 performance.
You can make all the upgrades you suggest and they will work, but in my opinion you are not going to hear any difference. The little amp is quite nice the way it is, but you will not be convinced of that, as all of us were, until you mod it and see for yourself.
One last thing: I would be more concerned about the volume control pot as in my post 1954 than anything else.
I have changed the inductors as in my previous posts and found that there was no audible change. Just an expense that didn't pay off. I would find 2.2uf caps with a much smaller voltage other than 450v. As for the opamp, your choice will work fine. I think you are wasting your time on changing that since this circuit is not high performance. Any noise figure that you may gain will be negated by the 2020 performance.
You can make all the upgrades you suggest and they will work, but in my opinion you are not going to hear any difference. The little amp is quite nice the way it is, but you will not be convinced of that, as all of us were, until you mod it and see for yourself.
One last thing: I would be more concerned about the volume control pot as in my post 1954 than anything else.
Well this depends. It's not so much as you hear it as it has other benefits in the circuit. Provided the value is as it should be, and they don't saturate, there could be a benefit.
Better filtering means less high frequency crap on the output. If that isn't filtered very good it can put strain on the speaker. It may have a benefit and still not hear it. That doesn't mean it's wasted money.
If you want to check this out, you could make some tests, put the old ones on one channel and scope both channels.
Well, to protect your speakers?
Here's how a class D output looks like:
Here's how a class D output looks like:
An externally hosted image should be here but it was not working when we last tested it.
Also have a look here and see how the output of this particular chip looks like, from different amps:
Budget T-Amp Shootout - Lepai vs. Indeed TA2020 - Page 6
I presume it's a very good idea to try and tame the high frequency crap as much as possible, using quality parts.
Budget T-Amp Shootout - Lepai vs. Indeed TA2020 - Page 6
I presume it's a very good idea to try and tame the high frequency crap as much as possible, using quality parts.
Here's a snippet from the ta2022 datasheet, directly from Tripath:
"Output inductor selection is a critical design step. The core material and geometry of the output filter
inductor affects the TA2022 distortion levels, efficiency, over-current protection, power dissipation and
EMI output. The inductor should have low loss at 700kHz with 80Vpp. It should be reiterated that
regardless of the systems maximum operating current, a 10A rating is required to ensure that peak
current conditions will not cause the inductor to saturate. During a short circuit event the inductor
current increases very quickly in a saturated core (see figure 6), compromising the current protection
scheme. A 10A rating is sufficient to ensure that current increases through the inductor are linear, and
provides a safety margin for the TA2022. There are two types of inductors available in the 10A range
that offers some EMI containment: they are the toroidal type and the bobbin (shielded) type inductor.
In bobbin construction, a ferrite shield is placed around the core of a bobbin inductor to help contain
radiated emissions. This shield can reduce the amount of energy the inductor can store in the core by
reducing the air gap, which can lower the peak current capability of the inductor. Typically, a 7-10A
shielded bobbin inductor will not have the peak current capability necessary to ensure that the core will not saturate during short circuit events; this is why they are not recommended for use with the
TA2022. Also it should be noted that shielded bobbin construction is not as effective as toroidal
construction for EMI containment.
Tripath recommends that the customer use a toroidal inductor with a Carbonyl-E core for all
applications of the TA2022. This core has a high peak current capability due to its low-µ Carbonyl-E
metal powder. A distributed air gap increases its’ energy storage capability, which allows for a small
footprint and high current capability. Carbonyl-E toroidal iron powder cores have low loss and good
linearity. The toroidal shape is ideal for EMI containment. Also, EMI can be further contained by sizing
the toroid to accept a full layer of windings. This aids in shielding the electric field. Tripath
recommends:
- Micrometals (Micrometals - Iron Powder Cores) Type-2 (Carbonyl-E) toroidal iron powder cores. The
specific core Tripath initially verified and used on the EB-TA2022 was a T94-2 (23.9mm
outer diameter) wound to 11uH with 19AWG wire. Since then Tripath has determined that
much smaller Carbonyl-E toroids will not saturate during high current events. Tripath has
also used T68-2 (17.5mm outer diameter) and the T60-2B/60(15.2mm outer diameter)
cores wound to 11uH with 22AWG with good success. If a smaller core is required, core
outer diameters as small as 15.2mm (T60-2) work well, but core temperature effects should
be tested. The T60-2 core did not saturate during short circuit testing, but maximum core
temperatures must be considered and multiple layer winding must be used to achieve
11uH. Multiple winding can increase winding capacitance, which may cause ringing and
increased radiated emissions. Bank winding techniques can minimize this effect. It should
be noted that at core temperatures above 130C the single build wire used by most inductor
manufacturers should be replaced with a heavy build wire. Micrometals does not provide
winding services, but many companies purchase directly from them and provide completely
finished inductors. Pulse Engineering has assigned a part number for the T68-2 wound with
44 turns of 22 AWG single build wire. The part number is PA0291.
- Amidon Inc./American Cores type-06 (Carbonyl-E) toroidal iron powder cores. Tripath has
used T690-06 (17.5mm outer diameter) cores wound to 11uH with good success. Amidon
carries type-06 cores in the 23.9mm to 15.2mm outer diameter range. They have assigned
a part number for the T690-06 wound with 44 turns of 22 AWG single build wire. This part
is approved by Tripath and is 690064422."
"Output inductor selection is a critical design step. The core material and geometry of the output filter
inductor affects the TA2022 distortion levels, efficiency, over-current protection, power dissipation and
EMI output. The inductor should have low loss at 700kHz with 80Vpp. It should be reiterated that
regardless of the systems maximum operating current, a 10A rating is required to ensure that peak
current conditions will not cause the inductor to saturate. During a short circuit event the inductor
current increases very quickly in a saturated core (see figure 6), compromising the current protection
scheme. A 10A rating is sufficient to ensure that current increases through the inductor are linear, and
provides a safety margin for the TA2022. There are two types of inductors available in the 10A range
that offers some EMI containment: they are the toroidal type and the bobbin (shielded) type inductor.
In bobbin construction, a ferrite shield is placed around the core of a bobbin inductor to help contain
radiated emissions. This shield can reduce the amount of energy the inductor can store in the core by
reducing the air gap, which can lower the peak current capability of the inductor. Typically, a 7-10A
shielded bobbin inductor will not have the peak current capability necessary to ensure that the core will not saturate during short circuit events; this is why they are not recommended for use with the
TA2022. Also it should be noted that shielded bobbin construction is not as effective as toroidal
construction for EMI containment.
Tripath recommends that the customer use a toroidal inductor with a Carbonyl-E core for all
applications of the TA2022. This core has a high peak current capability due to its low-µ Carbonyl-E
metal powder. A distributed air gap increases its’ energy storage capability, which allows for a small
footprint and high current capability. Carbonyl-E toroidal iron powder cores have low loss and good
linearity. The toroidal shape is ideal for EMI containment. Also, EMI can be further contained by sizing
the toroid to accept a full layer of windings. This aids in shielding the electric field. Tripath
recommends:
- Micrometals (Micrometals - Iron Powder Cores) Type-2 (Carbonyl-E) toroidal iron powder cores. The
specific core Tripath initially verified and used on the EB-TA2022 was a T94-2 (23.9mm
outer diameter) wound to 11uH with 19AWG wire. Since then Tripath has determined that
much smaller Carbonyl-E toroids will not saturate during high current events. Tripath has
also used T68-2 (17.5mm outer diameter) and the T60-2B/60(15.2mm outer diameter)
cores wound to 11uH with 22AWG with good success. If a smaller core is required, core
outer diameters as small as 15.2mm (T60-2) work well, but core temperature effects should
be tested. The T60-2 core did not saturate during short circuit testing, but maximum core
temperatures must be considered and multiple layer winding must be used to achieve
11uH. Multiple winding can increase winding capacitance, which may cause ringing and
increased radiated emissions. Bank winding techniques can minimize this effect. It should
be noted that at core temperatures above 130C the single build wire used by most inductor
manufacturers should be replaced with a heavy build wire. Micrometals does not provide
winding services, but many companies purchase directly from them and provide completely
finished inductors. Pulse Engineering has assigned a part number for the T68-2 wound with
44 turns of 22 AWG single build wire. The part number is PA0291.
- Amidon Inc./American Cores type-06 (Carbonyl-E) toroidal iron powder cores. Tripath has
used T690-06 (17.5mm outer diameter) cores wound to 11uH with good success. Amidon
carries type-06 cores in the 23.9mm to 15.2mm outer diameter range. They have assigned
a part number for the T690-06 wound with 44 turns of 22 AWG single build wire. This part
is approved by Tripath and is 690064422."
@jay1028: Thank you for your inputs, then I probably gonna hold off on the inductors and op amps, the replacement of the latter seems a daunting task as I have never soldered/desoldered SMD cips before. The thing is I will need metallized polypropylene film caps (as was expressedly suggested by some members over at Parts Express forums), and those are the only specs sold by mouser unfortunately. I could find lower voltage rated metallized polypropylene caps from Parts Express themselves but the shipping cost kind of defeats the purpose...
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