Yes, a definite improvement in sound, especially when playing at high volume levels
Be careful with soldering/placement, they MUST NOT touch anything metallic, they arc out. I used TO-220 adhesive sil pads to insulate the bottom from the diodes and also to hold them in place. I might add some heat resistant adhesive later.
col.
I found what seems to be a great power supply for the Lepai amp I bought on ebay. It's 13.5V/2.66A. I've been using it for a few weeks now. I bought it at advpower.com. The only catch is that they sell in bulk. Luckily, the minimum order was 2 which means I have a spare. I'm so pleased with my Lepai that I'm thinking about picking up another if I can find someone who likes DIYing enough that they'd help me improve it (I'm legally blind, so there's no way I'd be able to do that myself).
goodgnus said:
It is very difficult to find 13.5V, 14V 4A is much easier.
http://shop.ebay.com/items/?_nkw=14v+4a&_sacat=0&_trksid=p3286.m270.l1313&_odkw=12v+4a&_osacat=0
Has anyone else apart from Calamaro tried bypassing the tone controls? What difference does this make, does it sound bassier than when the tone controls are set to 0?
I was wondering, does this disable the volume control also?
Finally, if I was to use a 0.1uF capacitor instead of a 2.2uF cap when bypassing the tone controls, would I then have a HPF of around 100Hz? I'm wanting to try this out in the car, up to the front speakers, and I already have a sub for everything below 100Hz and I was wondering what the easiest thing to do here is.
I'm going away for the weekend in around 8 hours, and I'd love to try out the Lapei on the road...
Do you mean the tripath datasheet as I could not find a datasheet for this amp module?
I was wondering if it's possible to (easily) remove the 13.5v limit as according to tripath the max input voltage for the TA2020 is 16v, which would allow me to use it in the car.
My car when running has a voltage of around 14.4v.
Another option is to use diodes in series to drop the voltage, but this does waste a little power but it's not the end of the world.
I was wondering, does this disable the volume control also?
Finally, if I was to use a 0.1uF capacitor instead of a 2.2uF cap when bypassing the tone controls, would I then have a HPF of around 100Hz? I'm wanting to try this out in the car, up to the front speakers, and I already have a sub for everything below 100Hz and I was wondering what the easiest thing to do here is.
I'm going away for the weekend in around 8 hours, and I'd love to try out the Lapei on the road...
col said:
Do you mean the tripath datasheet as I could not find a datasheet for this amp module?
I was wondering if it's possible to (easily) remove the 13.5v limit as according to tripath the max input voltage for the TA2020 is 16v, which would allow me to use it in the car.
My car when running has a voltage of around 14.4v.
Another option is to use diodes in series to drop the voltage, but this does waste a little power but it's not the end of the world.
Mike, just turn the bass down, instant attenuation
If you look at the TA2020 datasheet you will see 2 lots of 4 diodes, one lot is the undershoot and the other is the overshoot. I checked on the Lepai board and the overshoot diodes are not there.
There is a 14v zener after the power supply, so this might protect the chip from overvoltage but I don't think it would sound so good.
The volume control is next up after the RCAs bypassing the tone controls won't affect it (i think).
Have a nice weekend
col.
If you look at the TA2020 datasheet you will see 2 lots of 4 diodes, one lot is the undershoot and the other is the overshoot. I checked on the Lepai board and the overshoot diodes are not there.
There is a 14v zener after the power supply, so this might protect the chip from overvoltage but I don't think it would sound so good.
The volume control is next up after the RCAs bypassing the tone controls won't affect it (i think).
Have a nice weekend
col.
Well all my stuff is packed, so now I've got the rest of the day to tinker an hope I don't melt anything!col said:Mike, just turn the bass down, instant attenuation
If you look at the TA2020 datasheet you will see 2 lots of 4 diodes, one lot is the undershoot and the other is the overshoot. I checked on the Lepai board and the overshoot diodes are not there.
There is a 14v zener after the power supply, so this might protect the chip from overvoltage but I don't think it would sound so good.
The volume control is next up after the RCAs bypassing the tone controls won't affect it (i think).
Have a nice weekend
col.
You're right, bass all the way down = no bass (yet treble all the way down seems to be normal level
)I've just tried it in the car, works great, even with the engine running no alternator whine, I guess a zener must be cheaper than 4 diodes, I'll have another look at the datasheet when I get time.
I'm not going to bypass the tone controls, as they are acting as my crossover right now, but if I get time I'm tempted to swap out the 4558 op-amp, I've only got a TL072 handy tho, I guess this may improve things a little?
Doh! I totally forgot in the e-bay listing it is sold as a car amp!panda360 said:
I can overthink things sometimes... I'll be sure to enjoy my weekend, we've have sun forecast for the whole weekend which is quite a rare thing in England.
Wouldn't bother with the TL072 it's about the same quality level as a JRC4558. Iv'e tried mine with NE5532 and LM4562 both of them sound great, the NE5532 is much cheaper though.
It's a really good feature to have a opamp pre with tone controls. It's much more versatile than just a volume pot, means you can use it with a wider range of inputs and different speakers. If you bypass the tone controls then you need speakers with a flat response ($$$). Would be really good to have a tone bypass switch so you had the option of off or on though. I notice that Lepai have done that with one of their other amps.
http://cgi.ebay.com.au/NEW-MINI-LEP...ca1ae0dd2&_trksid=p3286.c0.m14&_trkparms=66:2|65%3A1|39%3A1|240%3A1318|301%3A0|293%3A1|294%3A50
col.
Cheers, I'll leave the JRC4558 in for now then until I pick up something a little nicer.col said:
Bose chips!col said:
That is a good idea, I don't think it would be that hard to put a switchable tone bypass on this Ta2020 amp tho, if you just used a dual gang switch and put it inline with the bypass cap and resistor, then you should have a switchable tone control bypass shouldn't you?
Have you ever had this amp cut-out at all? I was trying it out in the car, and it's roasting hot in the car cabin. The whole amp case was warm, so I think it's gone into thermal protection.
It's now cooling off and I'll try it again in a bit... I hope I've not damaged it...
Thanks Calamaro for amazing mods and easy to follow photos!
1. I swapped cap in the PSU to a high quality Jamicon 4700uF 35V. Its physical size is just enough, so I didn't have to remove diode/inductor.
Immediately after the change, bass became fuller, richer, better controlled.
Could you please tell me why you connected 100nF film cap alongside with the big cap? As far as I know this additional cap shouldn't make any difference..
2. I bypassed tone controls according to your suggestion. Wow! What a difference! I can't believe this amp is sounding ever better! Sound is now like a crystal - very clean, almost analytic. However, for me it is lacking bass a little (previously my bass knob was set at 2 o'clock).. but there is no problem if you use eq
I couldn't find such a big (2.2uF) film caps in my area, so I got 2.2uF 100V Jamicon electrolytic caps. Also, used audiophile-grade OFC wire for routing the signal.
3. Has anyone tried replacing bulk capacitors? Is is worth?
Some photos:
1. I swapped cap in the PSU to a high quality Jamicon 4700uF 35V. Its physical size is just enough, so I didn't have to remove diode/inductor.
Immediately after the change, bass became fuller, richer, better controlled.
Could you please tell me why you connected 100nF film cap alongside with the big cap? As far as I know this additional cap shouldn't make any difference..
2. I bypassed tone controls according to your suggestion. Wow! What a difference! I can't believe this amp is sounding ever better! Sound is now like a crystal - very clean, almost analytic. However, for me it is lacking bass a little (previously my bass knob was set at 2 o'clock).. but there is no problem if you use eq
I couldn't find such a big (2.2uF) film caps in my area, so I got 2.2uF 100V Jamicon electrolytic caps. Also, used audiophile-grade OFC wire for routing the signal.
3. Has anyone tried replacing bulk capacitors? Is is worth?
Some photos:
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