After finishing the first channel I decided to have a listening comparisson of my new LM3886 NI amp and hi-cap snubbered PSU (courtsesy of Carlos), against my other LM3875 NI premium kit amp.
I'm convinced that there is a problem with my LM3875 implementation, but excuses aside I have found this new psu and amp combo to have some clear sonic improvements. And I mean clear.
This all began when comparing the LM3875 amp with a Proceed Amp 5 which is when the harsh top end and lack of bass in comparisson really stood out. Now there is much improved weight to the sound, and I could hear a huge improvement in the mid frequency seperation. (Hence why I need to relook at the LM3875 amp.)
There are still some inteference/grounding issues, but I feel this one will give the Proceed a run for its money.
Here's some pics:
Thought I'd have a little soldering exercise and went p2p to the extreme:
Finished amp section
I'm convinced that there is a problem with my LM3875 implementation, but excuses aside I have found this new psu and amp combo to have some clear sonic improvements. And I mean clear.
This all began when comparing the LM3875 amp with a Proceed Amp 5 which is when the harsh top end and lack of bass in comparisson really stood out. Now there is much improved weight to the sound, and I could hear a huge improvement in the mid frequency seperation. (Hence why I need to relook at the LM3875 amp.)
There are still some inteference/grounding issues, but I feel this one will give the Proceed a run for its money.
Here's some pics:
An externally hosted image should be here but it was not working when we last tested it.
Thought I'd have a little soldering exercise and went p2p to the extreme:
An externally hosted image should be here but it was not working when we last tested it.
Finished amp section
An externally hosted image should be here but it was not working when we last tested it.
C'mon Vikash, I really can't let you get away with that! 
You're comparing two completely different amps and construction methods here, so stating that just the change in the PSU makes the difference isn't really very rigorous, is it?
Anyway, go inverting, and then you will be giving the Proceed a proper test. I really must send you a couple of OPA548s...
You're comparing two completely different amps and construction methods here, so stating that just the change in the PSU makes the difference isn't really very rigorous, is it?
Anyway, go inverting, and then you will be giving the Proceed a proper test. I really must send you a couple of OPA548s...
Stop putting words in my mouth Mr. I would never be so bold as to say it was just the PSU. As it happens I've always been a little sceptical of *my implementation* of the rev 1 LM3875 kit which is to say that it was my first amp ever and I'm sure it has more potential. I really should get round to comparing it with the other LM3875 kits I've built (and reducing the 120mv offset )
I was expecting more bottom end with the new PSU - which it delivered, but I wasn't expecting the clarity change in the midrange which tells me there is something fundamental adrift in my LM3785 implementation, although with so many differences it really could be any or many things.
The bottom line remains though, it sounds better. Which is all I'm after really
On another note, I've been using the TB W3-871S monitors and they easily highlight changes between the Proceed and both chip amps. Quite impressive.
Nina, without swapping caps on the same amp it would be impossible to make a fair comparisson (Pinkmouse grrrrr). So far the mids are far better on the 3886 amp with 2200uf. The 3875 has 1500uf. Read from that and the above what you will
I would never be so bold as to say it was just the PSU. As it happens I've always been a little sceptical of *my implementation* of the rev 1 LM3875 kit which is to say that it was my first amp ever and I'm sure it has more potential. I really should get round to comparing it with the other LM3875 kits I've built (and reducing the 120mv offset ) I was expecting more bottom end with the new PSU - which it delivered, but I wasn't expecting the clarity change in the midrange which tells me there is something fundamental adrift in my LM3785 implementation, although with so many differences it really could be any or many things.
The bottom line remains though, it sounds better. Which is all I'm after really
On another note, I've been using the TB W3-871S monitors and they easily highlight changes between the Proceed and both chip amps. Quite impressive.
Nina, without swapping caps on the same amp it would be impossible to make a fair comparisson (Pinkmouse grrrrr). So far the mids are far better on the 3886 amp with 2200uf. The 3875 has 1500uf. Read from that and the above what you will
LM3875
It is interesting to hear about the differences. I am thinking about building the lm4780 next, but am still unsure if it will give me a better sound. The 3875 was quite nice apart from the small lack of base, but having very base orientated speakers, hasn't really been a problem.
But I can't afford to buy one and then be dissapointed.
By the way, i really love the Perspex amp. It has given me some new ideas, and i like anything thats not grey or aluminium.
It is interesting to hear about the differences. I am thinking about building the lm4780 next, but am still unsure if it will give me a better sound. The 3875 was quite nice apart from the small lack of base, but having very base orientated speakers, hasn't really been a problem.
But I can't afford to buy one and then be dissapointed.
By the way, i really love the Perspex amp. It has given me some new ideas, and i like anything thats not grey or aluminium.
Hi endzone...
have you try to "snubber" your LM3875 amp PSU?
After 6 months live happily with standard PS of Brian GT's LM3875 kit (second generation PCB), last night I try to "snubber" one side of the PS (I use dual mono configuration) and then compare one channel to the other...
The result is exactly what Vikash said... detail increased, separation between instrument is better, and the most important is the base... which improve a lot.... (I test using some music... on Jennifer Warnes "The Hunter" track, on the opening part... I never realise that there is a strong/heavy low string sounds (bowed double bass) ... but now I can hear it)
So... before investing on LM4780... try "snubber" your amp first...
It is considerably cheaper with the very obvious result...
I will definitely "snubber" the other PSU channel...
REgards,
---
David
have you try to "snubber" your LM3875 amp PSU?
After 6 months live happily with standard PS of Brian GT's LM3875 kit (second generation PCB), last night I try to "snubber" one side of the PS (I use dual mono configuration) and then compare one channel to the other...
The result is exactly what Vikash said... detail increased, separation between instrument is better, and the most important is the base... which improve a lot.... (I test using some music... on Jennifer Warnes "The Hunter" track, on the opening part... I never realise that there is a strong/heavy low string sounds (bowed double bass) ... but now I can hear it)
So... before investing on LM4780... try "snubber" your amp first...
It is considerably cheaper with the very obvious result...
I will definitely "snubber" the other PSU channel...
REgards,
---
David
Case
I really like perspex. In New zealand Alluminium is very expensive, so i had to look at different options. I found a company that throws away a lot of perspex, so decided to start working with that instead. So much better, i think it gives you more options. And if you don't have all the tools like myself, it's easier to work with. You also have the option of colour choice. And I got really sick of looking at alluminium cases anyway, but that's just me.
I really like perspex. In New zealand Alluminium is very expensive, so i had to look at different options. I found a company that throws away a lot of perspex, so decided to start working with that instead. So much better, i think it gives you more options. And if you don't have all the tools like myself, it's easier to work with. You also have the option of colour choice. And I got really sick of looking at alluminium cases anyway, but that's just me.
Hi Vikash,
Sorry, I do not state it clearly... I do use hi-cap PSU...with snubber...
Last night I do the samething to the other channel (that previously was not snubbered)... I'm surprised that this time the effect is not as so obvious than the previous channel...
I confirm it by swapping both channel and hear the music in mono (actually right channel music only)... the previously hi-cap-snubbered channel is clearly sound superior to the lately modified channel...
I wonder now what happen with the amp...?
Have you ever experience something like this?
Regards,
---
David
Sorry, I do not state it clearly... I do use hi-cap PSU...with snubber...
Last night I do the samething to the other channel (that previously was not snubbered)... I'm surprised that this time the effect is not as so obvious than the previous channel...
I confirm it by swapping both channel and hear the music in mono (actually right channel music only)... the previously hi-cap-snubbered channel is clearly sound superior to the lately modified channel...
I wonder now what happen with the amp...?
Have you ever experience something like this?
Regards,
---
David
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