I have been building amps/preamps for years, mostly tube but not all. I built my first chipamp (LM3886) a few months ago and it sounds great. I used the datasheet schematic.
I decided to make one with LM1875 chips just for the heck of it. Power is not an issue, my main speakers have 104db sensitivity.
I was planning on using the datasheet schematic for the LM1875 but was wondering if there are any changes to the datasheet schematic that may improve the sound. I am aware of the AN-1192 paper.
(Yes I know this is very subjective)
I decided to make one with LM1875 chips just for the heck of it. Power is not an issue, my main speakers have 104db sensitivity.
I was planning on using the datasheet schematic for the LM1875 but was wondering if there are any changes to the datasheet schematic that may improve the sound. I am aware of the AN-1192 paper.
(Yes I know this is very subjective)
I am planning on an 18-0-18 transformer so about plus and minus 25vdc.
Post in thread 'Various stuff free or for sale' https://www.diyaudio.com/community/threads/various-stuff-free-or-for-sale.392629/post-7221935
Here is my suggestion for LM1875 with +/-25V supply.
I use 47k resistors.
Attachments
If you built the 3886 amp already….lm1875 amp will not sound that different.
You could try Mauro Penasa RIP MyRef Lm3886 pump or Tom’s modulus86 amp.
I am not expecting it to have much difference. I really am just going to build it out of curiosity and possibly tweaking. I am familiar with the two amps you mentioned.
I guess you know this thread: https://www.diyaudio.com/community/...ion-and-used-in-a-composite-amplifier.346645/
I don't know the whole thread, but there are some working composite amp examples, such as #653 (that's a very similar tda 2050 version, however).
I don't know the whole thread, but there are some working composite amp examples, such as #653 (that's a very similar tda 2050 version, however).
Use factory.
The high pass capacitor C2 in voltage divider for gain can be slightly large if you want lower frequency response.
Not gonna change much already set to 3 Hz. Might measure lower distortion.
Usually just done in sim depending on the FFT used , people often make the cap larger since it lowers distortion in sim.
100uF or even 220uF, likely wont do much in real life.
Input resistor to ground is set to a specific value in factory to keep DC offset low on the output. R2
If you change the gain , input resistor typically needs to be 2 to 3k higher for DC offset.
Typically R2 and R4 would be same value in most amplifiers.
This case R2 is set slightly higher as mentioned for DC offset to be correct
The high pass capacitor C2 in voltage divider for gain can be slightly large if you want lower frequency response.
Not gonna change much already set to 3 Hz. Might measure lower distortion.
Usually just done in sim depending on the FFT used , people often make the cap larger since it lowers distortion in sim.
100uF or even 220uF, likely wont do much in real life.
Input resistor to ground is set to a specific value in factory to keep DC offset low on the output. R2
If you change the gain , input resistor typically needs to be 2 to 3k higher for DC offset.
Typically R2 and R4 would be same value in most amplifiers.
This case R2 is set slightly higher as mentioned for DC offset to be correct
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This will be Unpopular But 🙂 Built an 1875 Amp a while back... Using First world parts ,using the Datata sheet Curcuit .
Carefully and precisely.
Even built a Torroid Power supply (no stone left unturned 🙂
The thing Sounds Decent ..But as even Elliot Sound stated Clearly : the LM1875 is a Good amp but it is NOT a 'high end' one .
All claims notwithstanding.
I didn't believe his statement . However In retrospect the man is 100% correct.
Not even close to my Bespoke Lm3886 amp.
Nor even in the Same room as My DIY Firstwatt.
But have fun.. nonetheless.
Carefully and precisely.
Even built a Torroid Power supply (no stone left unturned 🙂
The thing Sounds Decent ..But as even Elliot Sound stated Clearly : the LM1875 is a Good amp but it is NOT a 'high end' one .
All claims notwithstanding.
I didn't believe his statement . However In retrospect the man is 100% correct.
Not even close to my Bespoke Lm3886 amp.
Nor even in the Same room as My DIY Firstwatt.
But have fun.. nonetheless.
If you want to go with the composite amp route, there is a nice article in magazine " Radio Electronics Nov1992 " issue about using LM1875 in every ( single, parallel, bridge and bpa ) combination. There is a link to the pdf in following forum page;
