Ground to chassis is fine, preferably at one of the phono input plugs.
Earth to chassis may do more harm than good depending on your earth-line. If not introducing hum, earth to chassis is an extra safety measure. You can dispense with such safety measures during experiments and test if you have hum from the earth connection.
thank you FF...the complete day "gardening" in the sun makes me very tired"
Just thinking about the gardening I have to do makes me tired.
In home confinement at least until 15 April.
Just thinking about the gardening I have to do makes me tired.
In home confinement at least until 15 April.
Hi
first sound impression of the UTC2050 chip amp i built. after running it 6 hours a notice no strange sound or something else. no on pop but a small off pop is noticed. sound is good - actually i find it a bit "hard in highs" and bloated in the bass area.... but will hear after some days on/off hours..
speakers are open baffle 12/5 8R because one of the two 12" sub is off.
chris
first sound impression of the UTC2050 chip amp i built. after running it 6 hours a notice no strange sound or something else. no on pop but a small off pop is noticed. sound is good - actually i find it a bit "hard in highs" and bloated in the bass area.... but will hear after some days on/off hours..
speakers are open baffle 12/5 8R because one of the two 12" sub is off.
chris
Hi
After every evening listening session i can´t say there is a different between my mock up amp LM1875 25V supply and the UTC amp ind the housing with 22V supply. both amp give me nice interpretation of different songs the last days.
so the UTC is a good chip
chris
After every evening listening session i can´t say there is a different between my mock up amp LM1875 25V supply and the UTC amp ind the housing with 22V supply. both amp give me nice interpretation of different songs the last days.
so the UTC is a good chip
chris
Attachments
Hi
After every evening listening session i can´t say there is a different between my mock up amp LM1875 25V supply and the UTC amp ind the housing with 22V supply. both amp give me nice interpretation of different songs the last days.
so the UTC is a good chip
chris
Many thanks for the test, Chris.
Both Fred and you have now given the UTC-TDA2050 a good listening test and both concluded that if there is a sound difference to the LM1875, it is marginal.
For European DIYers, genuine LM1875 is difficult to buy unless an importation procedure from the US is used with the costs that may add. The UTC-2050 is available from Reichelt.de at a considerably lower price than the LM1875, with less shipping costs and no extra importation fees.
Thanks a lot Chris for sharing your listening tests impressions.
I value your listening experience because no doubt your ear's frequency curve is way smoother than mine...
For me the sound in daily use is also excellent and i did some simple blind tests with friends (and my grandson..) to confirm my own impression.
No question the amp is delivering really good quality sound and (although there are some very minor nuances) the LM1875 and UTC 2050 are performing equally nice. For practical reasons i used the UTC 2050, because i had difficulties finding genuine LM1875 chips.
I also appreciate its total silence even with the ear on the speaker .
I value your listening experience because no doubt your ear's frequency curve is way smoother than mine...
For me the sound in daily use is also excellent and i did some simple blind tests with friends (and my grandson..) to confirm my own impression.
No question the amp is delivering really good quality sound and (although there are some very minor nuances) the LM1875 and UTC 2050 are performing equally nice. For practical reasons i used the UTC 2050, because i had difficulties finding genuine LM1875 chips.
I also appreciate its total silence even with the ear on the speaker .
Hi Fred
Yes the amps are very similar. i slightly prefer the UTC.Why? i dont know. maybe the lower gain helped him the have less fog in the middle of the presentation! maybe the real alu housing helped for better "interference blocking" - in the very high vocals and high hats the LM875 can do a very small bit better.
Did you try the amps with lower gain- as i have e.g. RF=15k = 20gain??
chris
Hi!
This thread has finally tipped me over the edge and I'm now in free fall down the DIY rabbit hole. I come from a completely different background (musician) so this is very new to me. I've started reading up as much as I can and it's getting increasingly more interesting as I'm slowly learning the basics.
I'm on my way to building the Folsom EC7293 amp in dual mono. Just waiting for some parts.
But! I've decided to build out a stereo amp from the ebay kit partly as a practice piece and also for my parents cabin. Have some ordered and have read through this thread, changing components and composing BOM's as I go along. I'm gonna go with new chips and all new components from Mouser and a Chinese SMPS.
I found this one. Should be good..?
DC 24V Dual Voltage Output +24V GND 24V 8A 380W HIFI Digital Audio Amplifier Board Power Adapter|Amplifier| | - AliExpress
It would be nice to see the latest/current layouts of the ebay-kit with lm1875 chips from you who have tinkered with it. A lot of components and values go in and out and it's not always easy for a noob to keep track.
Thanks to all of you extremely knowledgeable and generous people for sharing your experience and your findings!
/Hilding
This thread has finally tipped me over the edge and I'm now in free fall down the DIY rabbit hole.
I come from a completely different background (musician) so this is very new to me. I've started reading up as much as I can and it's getting increasingly more interesting as I'm slowly learning the basics. I'm on my way to building the Folsom EC7293 amp in dual mono. Just waiting for some parts.
But! I've decided to build out a stereo amp from the ebay kit partly as a practice piece and also for my parents cabin. Have some ordered and have read through this thread, changing components and composing BOM's as I go along. I'm gonna go with new chips and all new components from Mouser and a Chinese SMPS.
I found this one. Should be good..?
DC 24V Dual Voltage Output +24V GND 24V 8A 380W HIFI Digital Audio Amplifier Board Power Adapter|Amplifier| | - AliExpress
It would be nice to see the latest/current layouts of the ebay-kit with lm1875 chips from you who have tinkered with it. A lot of components and values go in and out and it's not always easy for a noob to keep track.
Thanks to all of you extremely knowledgeable and generous people for sharing your experience and your findings!
/Hilding
Hi vilding
SMPS...its cheaper here:
AC 85 265V to DC 24V 4A 6A 100W Switching Power Supply Board Power Supply Module|Switching Power Supply| | - AliExpress.
chris
SMPS...its cheaper here:
AC 85 265V to DC 24V 4A 6A 100W Switching Power Supply Board Power Supply Module|Switching Power Supply| | - AliExpress.
chris
So two of the wouldn't work for this application? 24vdc 6 amp should do it, right..?
Hi
for a small amp like the LM1875(+/-30V) or UTC2050(+/-25V) its max is 100VA/120VA with 18-0-18VAC or 15-0-15 VAC transformer.
FRed use a SMPS with about 300W:
dual group output +-24V and DC12V 300W power board MX50 L20 audio amplifier board power supply instead toroidal transformer|AC/DC Adapters| | - AliExpress
chris
for a small amp like the LM1875(+/-30V) or UTC2050(+/-25V) its max is 100VA/120VA with 18-0-18VAC or 15-0-15 VAC transformer.
FRed use a SMPS with about 300W:
dual group output +-24V and DC12V 300W power board MX50 L20 audio amplifier board power supply instead toroidal transformer|AC/DC Adapters| | - AliExpress
chris
Yeah that one looks a little bit more substantial. But shouldn't a 100 watt smps, even with losses, cope with one lm1875 chip? If I run them dual mono?
Haha I might buy a couple different ones over time just for experimentation...
Chris; thank you for pointing me here and for the great investigative work you've done on this little Ebay kit!
Haha I might buy a couple different ones over time just for experimentation...
Chris; thank you for pointing me here and for the great investigative work you've done on this little Ebay kit!
Vilding, you look fairly new to all this, did you have a look at JohnAudioTech's videos about that kit?
YouTube
When we say dual supply it is because those chips need to have some + and some - voltage supplies to be functional. So for instance, mine has 3 power inputs that are at : -20V, 0v, +20v
You will always need 2 boards to make it stereo, dual-mono would mean that you power 1 board from 1 power supply (so 2 supplies for 2 boards) but still requires you to have both supplies have dual power rails (negative, positive and ground).
I've been happy with the sound I get from that amp but still have a couple issues to solve. It is a fun journey though, and it is also my first amp.
Have fun, stay safe, read a lot
YouTube
When we say dual supply it is because those chips need to have some + and some - voltage supplies to be functional. So for instance, mine has 3 power inputs that are at : -20V, 0v, +20v
You will always need 2 boards to make it stereo, dual-mono would mean that you power 1 board from 1 power supply (so 2 supplies for 2 boards) but still requires you to have both supplies have dual power rails (negative, positive and ground).
I've been happy with the sound I get from that amp but still have a couple issues to solve. It is a fun journey though, and it is also my first amp.
Have fun, stay safe, read a lot