You do not really have sufficient drop-voltage for a cap multiplier that has real filter effect. You can put "voltage dropper" circuits between the outputs from the rectifier bridge and the power rail decoupling capacitors. You could also just use drop-diodes connected in series but the "voltage dropper" circuit is more compact and easier to cool in a controlled manner.
Use Darlington power transistors rated for some 10A, in a TO-220 housing, and ordinary 2V7 zener diodes.
Attachments
What is your opinion of the sound quality of the mono lm1875t board.
This is the one i got:
20W LM1875T Mono Channel Stereo Audio HIFI Amplifier Board Module DIY Kit 701828361563 | eBay
What kind of commercial amps would you say it competes well against
Would you say it competes well against most budget amplifier that retail at about £300, or do you think it goes into hi-fi territory.
Sorry i did not read all 73 pages. Apologies in advance.
This is the one i got:
20W LM1875T Mono Channel Stereo Audio HIFI Amplifier Board Module DIY Kit 701828361563 | eBay
What kind of commercial amps would you say it competes well against
Would you say it competes well against most budget amplifier that retail at about £300, or do you think it goes into hi-fi territory.
Sorry i did not read all 73 pages. Apologies in advance.
It's a good little amp and most are happy with it but as previously suggested, it is best to use your own parts and chips as usually these kits are supplied with fakes.
Soundwise it is very good indeed and I gave a completed pair to a member who wasn't expecting a great deal but was surprised with the sound quality. He said it was better than the other DIY SS and tube amps he had built. You have to remember it has low power output, limited protection and would suggest using rails around ±22VDC but will tolerate ±25VDC with speakers around 8 ohm.
As far as commercial amps go you do get more features and probably more power but this amp holds up well and would leave a lot of the budget amps behind. Compared against Neurochrome 3886DR and ESP P19, it was not shamed by these LM3886 based amps.
Have a scroll through the thread as you may find some comments that may assist and I think there was a mention about a Marantz amp.
Soundwise it is very good indeed and I gave a completed pair to a member who wasn't expecting a great deal but was surprised with the sound quality. He said it was better than the other DIY SS and tube amps he had built. You have to remember it has low power output, limited protection and would suggest using rails around ±22VDC but will tolerate ±25VDC with speakers around 8 ohm.
As far as commercial amps go you do get more features and probably more power but this amp holds up well and would leave a lot of the budget amps behind. Compared against Neurochrome 3886DR and ESP P19, it was not shamed by these LM3886 based amps.
Have a scroll through the thread as you may find some comments that may assist and I think there was a mention about a Marantz amp.
I started this Thread My (same) kits' were 2$. Only !usable part were the Circuit boards. Real Amp and Power supply parts run ~150$ (without cases tho).
Sounds? Decent, Good even, albeit heavily dependant on ; Source and Speaker quality
Better than a 1st world Lm3886 amp? mine aren't.
Not even similar to my Firstwatt amp.. but then chip amps are not in the same league.
IF after genuinely good amps at affordable prices? Look into into the pass forum (here) and the DIY audio shop offers.
V good value for money.. You will not do better . G 'luck
Hi goodguys
as rabbitz and bare wrote. the amp with genuine components will give you a "smile" - yes its a fine amp.
i am sorry that you do not want to go through all pages - because then you will read a lot of our journey here. I would be helpful to learn...
compare test are done between post 383 and 443
chris
as rabbitz and bare wrote. the amp with genuine components will give you a "smile" - yes its a fine amp.
i am sorry that you do not want to go through all pages - because then you will read a lot of our journey here. I would be helpful to learn...
compare test are done between post 383 and 443
chris
Hello,
I ordered a couple of the boards/kits with the through pads, and now I am trying to decide on a power supply. I think SMPS would be cheaper and certainly easier, but I would prefer to use the better of the two.
Is there any reason to go with a SMPS vs. Toroidal Linear Power Supply Unit?
Here are a couple of links to different SMPS that I think would work,
Amplifier Power Supply Module AC 110~220V to 15V/25V Dual Output Switching Power Supply 200W Voltage Regulator/Power Adapter|regulator filter|switching regulator efficiencyswitch audio - AliExpress
LCT300 Power amplifier switching power supply board 300W Amplifier SMPS DC +/ 24V/36V/42V and AUX 12V|AC/DC Adapters| - AliExpress
Page Not Found - Aliexpress.com
Is one a better choice than the other?
This seems to be the board I have seen used with the Toroidal units,
Rectifier POWER SUPPLY PSU BOARD FOR AUDIO POWER AMPLIFIER preamp AMP DIY kit|psu board|rectifier power supply boardpower amplifier board - AliExpress
Thank you,
David.
I ordered a couple of the boards/kits with the through pads, and now I am trying to decide on a power supply. I think SMPS would be cheaper and certainly easier, but I would prefer to use the better of the two.
Is there any reason to go with a SMPS vs. Toroidal Linear Power Supply Unit?
Here are a couple of links to different SMPS that I think would work,
Amplifier Power Supply Module AC 110~220V to 15V/25V Dual Output Switching Power Supply 200W Voltage Regulator/Power Adapter|regulator filter|switching regulator efficiencyswitch audio - AliExpress
LCT300 Power amplifier switching power supply board 300W Amplifier SMPS DC +/ 24V/36V/42V and AUX 12V|AC/DC Adapters| - AliExpress
Page Not Found - Aliexpress.com
Is one a better choice than the other?
This seems to be the board I have seen used with the Toroidal units,
Rectifier POWER SUPPLY PSU BOARD FOR AUDIO POWER AMPLIFIER preamp AMP DIY kit|psu board|rectifier power supply boardpower amplifier board - AliExpress
Thank you,
David.
Hi
As i remember right. fdenys used a SMPS with dual voltage(adjustable) and is happy.
my first boards i use the classical transformer 18-0-18 120V with cap with about 14000µF each rail.
my SMPS i ordered came very late and i haven´t compare it. if you read in other chip amp threads a lot of members are happy with the smps for chip amps and of course with class D amps.
the only thing what i remember (TPA3255...what is wrong-smps tests..) is the quality of feedback speed and power. if i read carefully then the smps during the dynamic "request" of an amp is not easy for low cost smps so the rule for me is to use a over dimesioned smps for amps.
i think the "noise" with actual smps are fine enough for these amps....I will compare it and report back...
dual group output +-24V and DC12V 300W power board MX50 L20 audio amplifier board power supply instead toroidal transformer|AC/DC Adapters| - AliExpress
chris
As i remember right. fdenys used a SMPS with dual voltage(adjustable) and is happy.
my first boards i use the classical transformer 18-0-18 120V with cap with about 14000µF each rail.
my SMPS i ordered came very late and i haven´t compare it. if you read in other chip amp threads a lot of members are happy with the smps for chip amps and of course with class D amps.
the only thing what i remember (TPA3255...what is wrong-smps tests..) is the quality of feedback speed and power. if i read carefully then the smps during the dynamic "request" of an amp is not easy for low cost smps so the rule for me is to use a over dimesioned smps for amps.
i think the "noise" with actual smps are fine enough for these amps....I will compare it and report back...
dual group output +-24V and DC12V 300W power board MX50 L20 audio amplifier board power supply instead toroidal transformer|AC/DC Adapters| - AliExpress
chris
SMPS
@Davefred
you could consider the audio SMPS which electronically looks identical to the version i am using: 300W outputs +-24V 36V 48V and Dual 15V single DC12V HIFI Audio amplifier Power Board power supply instead toroidal transformer|AC/DC Adapters| - AliExpress
Note: this SMTP accepts ac mains sources as from 88V (to 240V)
The price is attractive and you have +- 24v adjustable outputs, within + or - 10%. Also + and - 12 and 15v for auxillary items, preamps, a fan etc.
In my case i could adjust the voltage between approx. (+ and -) 22-27 V for the double 24v version.
From my experience the adjustable voltage really is indispensable.
However i do not see a small potentiometer on the photo's, so check with the seller. The +-10% range however, is in the description/spec
This SMPS is specifically made for audio applications and optimized for low noise.
The SMPS is on a compact aluminium chassis, which greatly simplifies the amplifier's construction.
In my case the amplifier is absolutely quiet, no noise, hum even with your ear on the speaker.
Fred
@Davefred
you could consider the audio SMPS which electronically looks identical to the version i am using: 300W outputs +-24V 36V 48V and Dual 15V single DC12V HIFI Audio amplifier Power Board power supply instead toroidal transformer|AC/DC Adapters| - AliExpress
Note: this SMTP accepts ac mains sources as from 88V (to 240V)
The price is attractive and you have +- 24v adjustable outputs, within + or - 10%. Also + and - 12 and 15v for auxillary items, preamps, a fan etc.
In my case i could adjust the voltage between approx. (+ and -) 22-27 V for the double 24v version.
From my experience the adjustable voltage really is indispensable.
However i do not see a small potentiometer on the photo's, so check with the seller. The +-10% range however, is in the description/spec
This SMPS is specifically made for audio applications and optimized for low noise.
The SMPS is on a compact aluminium chassis, which greatly simplifies the amplifier's construction.
In my case the amplifier is absolutely quiet, no noise, hum even with your ear on the speaker.
Fred
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With two mono boards on a SMPS, can you use this single board for speaker protection?
1PCS UPC1237 Speaker Protection Board Dual Omron Relay For HIFI Amplifier DIY Speaker Kit|Integrated Circuits| - AliExpress
I am probably using the wrong search terms, as I cannot find what the right item, what kind of seperate transformer would you use to get to get AC to this board from 110v mains?
Would this transformer work?
https://www.mouser.ca/ProductDetail/Hammond-Manufacturing/166JA12?qs=gF4h2Znc3LA0CLfGP4N7iQ==
Thank you,
David.
Hi
its a small housing and its was with shipping and tax about 58 euro. now its getting expensive.
if you read in this thread you will find some pics. 2 amp boards a psu board 35V caps and a 18-0-18 Volt 120VA transformer is enough for the housing.
if you use 4 R speakers you should go down with the voltage of the transformer to 15-0-15 120VA-especially if you use the UTC 2050 chip.
housing:
Douk Audio Amplifier Chassis General Aluminum Shell Pre Amp Enclosure DIY Box|amplifier chassis|audio amplifier chassisaudio amplifier - AliExpress
look at modushop maybe you will find other housings.
chris
NO! this is to less for 2 amp boards. its a 12V - 12VA transformer with 1amp current.
please us in minimum a 80VA transformer. so a rule of thumb.
one channel can deliver in 8R speakers about 30W so you have 60Watt total + factor 1,5"dynamic reserve".....--> so its about 90VA. so i found that a 100VA-120VA is the same price with more power reserves.
please look at transformer with 2 secondary windings- or use a dual rail SMPS- less work
and same result as fred wrote.chris
Hi david
please take your time and read through this tread- you will learn a lot
.if you use a chip LM1875 from a vendor like mouse , farnell, digikey etc...then you can expect that this chip has a kind of self protection..---> thermal + short cut. read here the datasheet.
so then a speaker protection board is not really needed. if you have space and you want to have a speakers protection then use it.
chris