Hi DizRotus, how did you control the line voltage to the Meanwell psu. Sorry I'm very green on this topic and honestly this is gonna be my first amplifier project
If you can post a picture of the internal of your amp, I would really appreciate it.
Thanks and regards,
Anton
I posted a picture of the inside of my amp in post #266.
Ground (yellow) to chassis, then to PSU
Live (red) to switch, then to PSU
Neutral (black) to PSU.
The IEC plug has a built in fuse.
Hope that helps.
Mike
I'm curious. Does your PS stay on for a few seconds after disconnecting power to it? If so, if you cut power to the PS and switch the EVM to reset at the same time, does the PS stay on long enough for the EVM to complete it's power down sequence and not pop on power down?
Thanks, Mike
I got a small thump at power on and a smaller one on power off using a linear PS.
I'm planning to control the power and enable switch from the preamp. Sometimes it causes a nasty thump at power on. And also implement a time delayed shutdown of the power amp from the preamp. One less thing to turn on and off.
I'm planning to control the power and enable switch from the preamp. Sometimes it causes a nasty thump at power on. And also implement a time delayed shutdown of the power amp from the preamp. One less thing to turn on and off.
That's exactly what I did with my case. The front plate is too thick to drill (5 mm aluminum) and the side is much thinner (stamp steel). So I placed a small toggle switch on the right side panel. If I knew I have to drill a hole, I would have bought a chassis that has opening on the front panel to accommodate it
. Regards,
Mike, this is a big help for a newbie like me. Went back to your post & downloaded the pic for reference. I appreciate it.
Lo_Tse - I'm thinking wooden side panels but aluminum back & bottom for the enclosure. I will be drilling holes for ventilation, will there be any issues with my chassis material choice? Thanks.
Lo_Tse - I'm thinking wooden side panels but aluminum back & bottom for the enclosure. I will be drilling holes for ventilation, will there be any issues with my chassis material choice? Thanks.
That's exactly what I did with my case. The front plate is too thick to drill (5 mm aluminum) and the side is much thinner (stamp steel). So I placed a small toggle switch on the right side panel. If I knew I have to drill a hole, I would have bought a chassis that has opening on the front panel to accommodate it
Regards,
I am no expert but in general, metal chassis will provide shielding of EMI. When I was playing with the 3118 and 3116 class D amps , there were some minor interference (coming from the amps) with radio signals.
The chassis I am using for the 3255 now is all metal (stamped steel on all side except the front). My chassis has ventilation slots on the bottom and top. Under normal use (depend who you are), the amp and PSU barely get warm. So I think ventilation is not an issue.
Regards,
The chassis I am using for the 3255 now is all metal (stamped steel on all side except the front). My chassis has ventilation slots on the bottom and top. Under normal use (depend who you are
), the amp and PSU barely get warm. So I think ventilation is not an issue. Regards,
test with proper DAC will take a little longer
The test with the DDDAC 1794, will take a little longer.
Long story, short, way back, I modified the 12 Volt supply of the DDDAC with a bigger Trafo (xformer), and on initial testing (listening for a few minutes) the stiff wires from the trafo to the PSU main board "broke" off, bad soldering / plan from my side
So I will go back to the original trafo on the DDDAC 12 Volt PSU, but that will take a few day's more, we are having relatives over for a longer visit.
The few minutes that I was able to have the DDDAC 1794 connected to the TPA3255EVM, and playing I listened to a much more "brilliant" sound ( when playing from the Pod the sound was dull ) as test track I used the first track of the "2Meter Sessies, Vol. 1" CD, Melissa Etheridge, "Bring me some water".
when playing from the Pod I had no noise what so ever between the tracks or when muting the Pod, when playing from the DDDac I had some noise on the speakers, either grounding ( or the defective soldering in the 12 V PSU ) to be determined later.
A small note on the PSU and TPA3255EVM temperature when playing music, the PSU only gets luke warm ( You can keep your hand on the PSU case for long time), same for the heatsink of the TPA3255EVM, gets only Luke warm, this was play at small room volume levels.
Happy listening
Grtz
Bert
The test with the DDDAC 1794, will take a little longer.
Long story, short, way back, I modified the 12 Volt supply of the DDDAC with a bigger Trafo (xformer), and on initial testing (listening for a few minutes) the stiff wires from the trafo to the PSU main board "broke" off, bad soldering / plan from my side
So I will go back to the original trafo on the DDDAC 12 Volt PSU, but that will take a few day's more, we are having relatives over for a longer visit.
The few minutes that I was able to have the DDDAC 1794 connected to the TPA3255EVM, and playing I listened to a much more "brilliant" sound ( when playing from the Pod the sound was dull ) as test track I used the first track of the "2Meter Sessies, Vol. 1" CD, Melissa Etheridge, "Bring me some water".
when playing from the Pod I had no noise what so ever between the tracks or when muting the Pod, when playing from the DDDac I had some noise on the speakers, either grounding ( or the defective soldering in the 12 V PSU ) to be determined later.
A small note on the PSU and TPA3255EVM temperature when playing music, the PSU only gets luke warm ( You can keep your hand on the PSU case for long time), same for the heatsink of the TPA3255EVM, gets only Luke warm, this was play at small room volume levels.
Happy listening
Grtz
Bert
I received this board (TPA3255EVM) and paired it up with a MEANWELL LRS-350-48. I'm using a Denon AVR-x3300w as a preamp and I'm running Klipsch RF-7iis. I immediately noticed a couple of things within the first 10 seconds. 1. The audio level or gain is roughly 3db less than just hooking the speakers directly up to the AVR itself. I was getting 82db with the TPA3255EVM hooked up and 85db without (speakers hooked directly to the AVR. 2. The sound is either neutral or on the warm side, at least compared to the AVR. This is neither a good or bad thing. The sound is great, maybe a little more rounded and not quite as harsh(although the amp and the AVR both sound good). The one thing I didn't like is that I believe there was clipping(amber light?) around 90-95db. Have I reached the limits of the amp or is this more indicative of the power supply? If I have reached the limits of the amp, does anyone use these as mono-blocks? The sound level is great for 95% of my listening, but there are times when I'm alone drinking homebrew and I want that extra kick to the face! I have not adjusted any jumpers, the amp is as exactly as it came out of the box. I'm fairly new to the amp world so I'm learning as I go. Thanks for any input!
Mark
Mark
The specs for Klipsh RF7ii shows 101dB efficiency and impedance "8 ohms compatible", which - just guessing - means 6-7 ohms.
In default BTL mode with power supply at 53.5V, the tpa3255 should be able to deliver around 150Wpc continuous to these speakers @0.1% THD...30W more than the denon's ~120Wpc. And the lrs-350 should be able to handle this. What voltage are you running?
The specs for AVR-x3300w show the analog outputs are rated for 1.2V, but doesn't show an output impedance spec. The tpa3255 expects a more typical 2V at the inputs.
So I suspect the denon's analog outputs are underdriving the tpa3255 when compared to the internal preamp->amp connections. Do you have another source you can use for comparison?
In default BTL mode with power supply at 53.5V, the tpa3255 should be able to deliver around 150Wpc continuous to these speakers @0.1% THD...30W more than the denon's ~120Wpc. And the lrs-350 should be able to handle this. What voltage are you running?
The specs for AVR-x3300w show the analog outputs are rated for 1.2V, but doesn't show an output impedance spec. The tpa3255 expects a more typical 2V at the inputs.
So I suspect the denon's analog outputs are underdriving the tpa3255 when compared to the internal preamp->amp connections. Do you have another source you can use for comparison?
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In my experience a 5mm thick aluminum panel is much easier to drill than steel sheet metal. First center punch it, to make sure the drill bit doesn’t wander, then use a quite thin drill (like 4mm) and drill through carefully. Then keep drilling the hole with larger and larger drill bits until it’s what you need. Easy peasy if you don’t try to drill a big hole all at once which is guaranteed to be off center.
Actually this is the best way to drill steel sheet metal too, it’s just is a bigger PITA.
Actually this is the best way to drill steel sheet metal too, it’s just is a bigger PITA.
That's exactly what I did with my case. The front plate is too thick to drill (5 mm aluminum) and the side is much thinner (stamp steel). So I placed a small toggle switch on the right side panel. If I knew I have to drill a hole, I would have bought a chassis that has opening on the front panel to accommodate it
Regards,
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Thanks for your response! When I first hooked up the power supply I was at 48V, I've since bumped the voltage up to 50v(I wasn't sure if I should go higher or not). I haven't really tested the volume since I've made the change. Can I get a stable 53.5V out of this power Supply?
I did make what I thought was going to be a marginal improvement actually made a HUGE difference. I replaced my 20 year-old flat 16ga oxidized speaker wire with new 12ga. I noticed a HUGE difference in the bass department. My speakers now seem "alive". I have a feeling the volume will be more than adequate after swapping the wire out. I'll have to check the voltage of the pre-outs and maybe try a different source just for kicks. Thanks again!!
You are probably right. I don't have much experience drilling. I figure that cutting thru a 5 mm think aluminum piece has to be tougher than drilling thru a thin stamped steel panel (< 1 mm thick). The other reason that I didn't want to drill on the front panel was because I did not want to "ruin the look"
. I did what you described when I drilled that hole on the side panel - center punched first, start with a small drill bit, then a large one. It was still off center a little which I blamed it on the paint baked onto the metal. Using a hand held drill did not help thing either.
I ordered my EVM last year, but only got around to powering it up in an old amp chassis with a Meanwell LRS-350-48 SMPS in the last couple of days.
So far very positive impressions, though I haven't done much listening using it "full range" driving passive crossover speakers.
I have put it into my active system driving some 15" low frequency drivers and so far very good. The speakers are Lorantz C390BX1 - http://www.tubeaudio.com.au/content/lorantz/A-C390X-B1-8.pdf
Source is a optical spdif -> miniDSP with opamp buffers to help manage gain.
These speakers are 98dB sensitive, so I've been getting various levels of hiss with the other amps I have tried, but with the TPA3255 it is dead quiet at "ear to the cone" levels of closeness, this is great!
Also I'm not sure if anyone else has measured this, but using a WattsClever power consumption meter the LRS-350-48 + TPA3255 combo uses 7.7 watts idle at the power socket - a step down from the 11.4W that the previous IRS2092 amp I was using consumed.
So far very positive impressions, though I haven't done much listening using it "full range" driving passive crossover speakers.
I have put it into my active system driving some 15" low frequency drivers and so far very good. The speakers are Lorantz C390BX1 - http://www.tubeaudio.com.au/content/lorantz/A-C390X-B1-8.pdf
Source is a optical spdif -> miniDSP with opamp buffers to help manage gain.
These speakers are 98dB sensitive, so I've been getting various levels of hiss with the other amps I have tried, but with the TPA3255 it is dead quiet at "ear to the cone" levels of closeness, this is great!
Also I'm not sure if anyone else has measured this, but using a WattsClever power consumption meter the LRS-350-48 + TPA3255 combo uses 7.7 watts idle at the power socket - a step down from the 11.4W that the previous IRS2092 amp I was using consumed.
Thanks for the power consumption level. The TPA3255 has been in the system for a few months and I've been pretty happy with it so far. Earlier in the week I decided to leave it on overnight just to see if it sounded different being left on. Things got busy and it ended up being two days later and I was quite surprised at how much smoother the amp sounded. It's a nice sonic improvement.
If it uses 7 or 8 watts at idle it's OK to do that every now and again.
Hello,
Can somebody recommend this board?
Klasse D TPA3255 MINI HIFI AUDIO Digitale Versterker Boord 300 W + 300 W DC50V in Klasse D TPA3255 MINI HIFI AUDIO Digitale Versterker Boord 300 W + 300 W DC50V van Versterker op AliExpress.com | Alibaba Groep
I am looking for an fan-less option for 18" open baffle speaker (bass only, active crossover). I have a Crown XLi but the fan is always on.. Tried other amps but none sounds as good as Crown. I want to try a class D (cheap one).
Thanks!
Can somebody recommend this board?
Klasse D TPA3255 MINI HIFI AUDIO Digitale Versterker Boord 300 W + 300 W DC50V in Klasse D TPA3255 MINI HIFI AUDIO Digitale Versterker Boord 300 W + 300 W DC50V van Versterker op AliExpress.com | Alibaba Groep
I am looking for an fan-less option for 18" open baffle speaker (bass only, active crossover). I have a Crown XLi but the fan is always on.. Tried other amps but none sounds as good as Crown. I want to try a class D (cheap one).
Thanks!
Does this unit (TI version TPA3255) self destruct when turned on without speakers connected like the TPA3118? If I don't want to blow up my test speakers (although that is precisely what they are for ), I guess some 8 ohm load resistors should be installed to measure DC prior to hooking up would be the best approach? I am almost certain that this is the case, but want to make sure I'm not missing something.
), I guess some 8 ohm load resistors should be installed to measure DC prior to hooking up would be the best approach? I am almost certain that this is the case, but want to make sure I'm not missing something.