Buying 1000 tpa chips for us seems like a lot, but many of these chinese ampboards are produced in such numbers that for example 10.000 amps can ship instantly, and that seems to be from sources that are probably resellers.
Load is part of outputfilter (without the load it oscillates), so the load the filter was designed for is needed to check distortion. Also out of audioband noise tends to mess with distortion readings of audioband frequencies, the meter becomes inaccurate, the readings random. AES17 (I recall) is used to get reliable numbers till ~6000 Hz
Load is part of outputfilter (without the load it oscillates), so the load the filter was designed for is needed to check distortion. Also out of audioband noise tends to mess with distortion readings of audioband frequencies, the meter becomes inaccurate, the readings random. AES17 (I recall) is used to get reliable numbers till ~6000 Hz
Obvious poor fake Panasonic FR's could be nice quality components, they are so nice they didn't need to produce better looking fakes?
The main cap used with the capacitance multiplier is not a Panasonic knock off. Its a Lelon branded cap.
An externally hosted image should be here but it was not working when we last tested it.
AES17 filter is needed if you use a conventional distortion meter, that removes the fundamental tone and measures what remains (harmonics + noise).
I used a selective voltmeter (Wandel und Goltermann PMG 13) with balanced input: it has a tunable filter (with bandwidth as narrow as 10 Hz) that can be manually tuned on each single harmonic; in this way, one can measure the level of each harmonic, also in presence of strong noise (it is similar to a spectrum analyzer).
Might be a Lelon, might not be a Lelon. Look a little further for the fake Panasonic FR's
My initial foray into the TPA amps was with the SMSL SA-36a Pro (TPA3118, non the TA2020 version). The Volt+ is a better implementation of the chip than the 36a Pro.
On the plus side, the turn off pop is barely audiable compared to the thump from the 36a Pro (on 86db speakers). It sounds more robust and enjoyable than the 36a Pro. Where the 36a Pro can sound abit thin (even with the panasonic oscon swap in the decoupling positions), this is warmer toned in comparison. I've also tested the board with a shunt styled pre (with onboard attenuator at full swing). Bueno!
On the downside, the volume position on the board is a abit of an engima. In comparison to the 36a Pro, this board only accounts for a single pitch for the signal cap. The 36a Pro allows for the flexibility of a 2 cap sizes on the PCB (to up a 22.5mm pitch). This is not entirely relevant as the Volt+ board is well voiced.
Relative to the 36a Pro, the Volt+ is more of a step up as opposed to an incremental upgrade. My 36a Pro will now likely join its 36a (non pro) sibling in a trip to the classifieds.
On the plus side, the turn off pop is barely audiable compared to the thump from the 36a Pro (on 86db speakers). It sounds more robust and enjoyable than the 36a Pro. Where the 36a Pro can sound abit thin (even with the panasonic oscon swap in the decoupling positions), this is warmer toned in comparison. I've also tested the board with a shunt styled pre (with onboard attenuator at full swing). Bueno!
An externally hosted image should be here but it was not working when we last tested it.
On the downside, the volume position on the board is a abit of an engima. In comparison to the 36a Pro, this board only accounts for a single pitch for the signal cap. The 36a Pro allows for the flexibility of a 2 cap sizes on the PCB (to up a 22.5mm pitch). This is not entirely relevant as the Volt+ board is well voiced.
An externally hosted image should be here but it was not working when we last tested it.
Relative to the 36a Pro, the Volt+ is more of a step up as opposed to an incremental upgrade. My 36a Pro will now likely join its 36a (non pro) sibling in a trip to the classifieds.
An externally hosted image should be here but it was not working when we last tested it.
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Cheers Poultrygeist.
The power plug is an awkward size. Thankfully there was an adapter supplied for the much more common 5.5 x 2.5mm or 5.5 x 2.1mm DC power connector.
This (to the best of what i can measure of the adapter) is around 6.2 x 3mm. I am unable to measure the socket on the board.
The power plug is an awkward size. Thankfully there was an adapter supplied for the much more common 5.5 x 2.5mm or 5.5 x 2.1mm DC power connector.
This (to the best of what i can measure of the adapter) is around 6.2 x 3mm. I am unable to measure the socket on the board.
An externally hosted image should be here but it was not working when we last tested it.
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You're very close.
My visit to Radio Shack this morning tells me the board takes a 6.3 mm OD X 3 mm ID male plug. ( dark green tip ). It is an weird size and I found one right angle adaptor on eBay which will allow for a smaller enclosure.
http://www.ebay.com/itm/1x-DC-5-5-x...428340?hash=item43e0914fb4:g:SxgAAOSwHnFVvIPW
My visit to Radio Shack this morning tells me the board takes a 6.3 mm OD X 3 mm ID male plug. ( dark green tip ). It is an weird size and I found one right angle adaptor on eBay which will allow for a smaller enclosure.
http://www.ebay.com/itm/1x-DC-5-5-x...428340?hash=item43e0914fb4:g:SxgAAOSwHnFVvIPW
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Volt+ quick review:
Pros:
Good detail, no turn on thump that I could notice.
Cons:
I also noticed the slightly odd sized plug. When I do the final build I plan to use a power board and may remove the plug anyways. Current PS was from a 19v 5a laptop supply.
I was using an Audient ID14 soundcard as one source and an XDuoo X3 (portable mp3 with line out). The Audient was 3vrms and the XDuoo was 1.5 so my sources were not the ideal 2.1vrms.
I compared the Volt + against an Amp 6 basic that I made myself a few years back. The Volt+ did not have a turn on thump that I could hear. The Amp 6 did. Compared to the Amp6 (TA2020), the Volt + has more detail and punch. In addition, I am hope to compare the Volt + in a few weeks with another amp and source. It could take a while since I am considering a few options.
The amp 6 kit was more expensive at the time and is probably considered old technology at this point. It shows how much increased production and RnD has changed things in a few years given the current prices and quality you can get in such a small form factor.
Pros:
Good detail, no turn on thump that I could notice.
Cons:
I also noticed the slightly odd sized plug. When I do the final build I plan to use a power board and may remove the plug anyways. Current PS was from a 19v 5a laptop supply.
I was using an Audient ID14 soundcard as one source and an XDuoo X3 (portable mp3 with line out). The Audient was 3vrms and the XDuoo was 1.5 so my sources were not the ideal 2.1vrms.
I compared the Volt + against an Amp 6 basic that I made myself a few years back. The Volt+ did not have a turn on thump that I could hear. The Amp 6 did. Compared to the Amp6 (TA2020), the Volt + has more detail and punch. In addition, I am hope to compare the Volt + in a few weeks with another amp and source. It could take a while since I am considering a few options.
The amp 6 kit was more expensive at the time and is probably considered old technology at this point. It shows how much increased production and RnD has changed things in a few years given the current prices and quality you can get in such a small form factor.
Hi, I removed the 4 pots of my tpa3116 and put 2 inch cables on every pot pin, so now they are more separated each other, which was I was looking for. I did this because I wanted them more separated once mounted on an enclosure box.
Now the amp is making a lot of weird noises at the background, although the music can be played with good quality. Is that so critic for these circuits having the pots as close as possible to the amp chip? Maybe thats the reason theres no possible using potentiometer extensions... any idea? I had no noises before removing the pots, so the power supply its not the fault.
Now the amp is making a lot of weird noises at the background, although the music can be played with good quality. Is that so critic for these circuits having the pots as close as possible to the amp chip? Maybe thats the reason theres no possible using potentiometer extensions... any idea? I had no noises before removing the pots, so the power supply its not the fault.
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Twist the wires between the board and the pot. For a 6-pin pot such as volume control, I'd twist together the 3 wires from each channel. So you would have a L 3-wire twist and a R 3-wire twist.
If it's really bad, you could use "shielded twisted pair" ethernet cable. YOu could get a 1m/3ft cable from NewEgg shipped for $4.50 and cut off the connectors and scavenge the wire. Beware the cheapo Chinese flat cables. The wire is too light to work with, strip, solder, etc.
If it's really bad, you could use "shielded twisted pair" ethernet cable. YOu could get a 1m/3ft cable from NewEgg shipped for $4.50 and cut off the connectors and scavenge the wire. Beware the cheapo Chinese flat cables. The wire is too light to work with, strip, solder, etc.
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I used usb cable, without the shield. (I stripped all wires and soldered them separated). Should I try this time using the shielded cover? Usb cable has 5 wires, counting the ground or shield. Every double pot has 2 pin connected to ground, so I am jumping them and soldering there an unique ground cable, so I have 5 cables for every double pot
.If you have not already done, try to mount the pots on a metallic panel and connect the panel to ground
Do you think the cause would be that there was no load in the subwoofer line? I anyway kept the bass pot all at minimum level because right now I don't have any bass speaker available to connect it there. Few days ago I tried a setting with all the 3 speakers connected and it worked fine, but that was before extending the pots. I will try asap with a subwoofer load and comment what happened.
What I observed with this new setting, was that the potentiometer cables were very sensitive to the touch even when I touched them in the plastic section, and not because bad soldering contacts, but electrostatic in my finger I think. Anyway the buzz was present without any touch, it was like it was reading some weird RF patterns from air or somewhere.
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Leaving an output unloaded can cause oscillation and possibly damage the amplifier; use a 4 - 16 ohm resistor or, if you don't have it, connect a spare speaker (even a little one, if you keep the output level near to zero).
Concerning the noise, did you try to mount the pots on a metallic panel?
Keep the pots as fas as possible from transformer and AC cable.
Ohh, I have some tiny 2" 8ohm loud speakers, then I am going to connect one in the subwoofer line and keep the volume low. I still did not try the metallic panel, will first try the bass load and see if noises get off. thanks.
If loading the woofer output helps, you could use a resistor for the final implementation (higher ohms so as not to suck up power).
Likely your picking up noise from the amp itself. To be sure, I'd move the set up around to see if it's coming from external to the amp.
I would keep the shield in place and ground the shield as well (both ends).
You mentioned it's not an issue when playing music. Is this problem when there isn't a source is connected to the amp's inputs, or, when the source is connected but not providing a signal (e.g., source is powered down, between tracks, etc.)?
You can mimic the metallic panel solution by tying together the metallic bodies of all 4 pots. Just a wire sandwiched between the mounting nut/washer spanning the pots. I've seen amps come from the MFG with this approach.