Revival of incredible LM3886 design

[udailey]

Thanks for the vote of confidence. I am psyched about the project.
With your commitment we are at 50-54 kits. So halfway there and only a week since we started the buy. I am confident that we will have all hundred by 10 more days or perhaps two weeks.
Brian from Twisted Pear will give support and I will help when I can chime in, but, this is DIY audio. There has hardly ever been a lack of support. Questions never go unanswered unless the person asking is really taking liberties with their manners.
After all boards are spoken for give us min two weeks max one month to get everything to our houses and kitted up. We are not purchasing until we have payments. Payments will be paypal. We will ship overseas for our overseas DIYers. All shipments will have some sort of shipping confirmation and insurance. Shipping will be an additional cost to the ~$65 per pair.
There is already a thread here, a very very long thread, that documents the build. Many very knowledgeable DIYers have contributed and even though it has seen little activity since 2006 this thread still instantly answers questions.
If you are concerned about the complexity of this build... dont be. This is a silkscreened and schematic'd board. You will have a BOM, Silkscreen, schematic, and DIY to help you. Just put the components where they go and solder well. It will work. Chip amps are simple things and there is no twiddling with bias pots here, no measurements will be necessary. Just build it and turn it on.
Uriah

[udailey]

Oh, and Tom,
We are searching for good prices on components but quality is NOT compromised in any way. We are sticking to the BOM developed by Mauro and Twisted Pear. This is not a Mundorf and Obligatto BOM but it is a Panasonic FC/FM BOM and thats good stuff as well.
Uriah

[glt]

Hi, this is a kind of dumb question, but was not able to find examples of this amp with an active crossover configuration, so, are these suitable for a bi-amp, tri-amp configuration? I want to two amps to drive two woofers, each with a simple second order low pass filter at 1000 Hz, and one amp with a simple first order high pass for the ribbon (this is just a duplication of the passive crossover). Also is the DC protection circuit good enough to leave the ribbon unprotected (with a cap) and feed the amp straight to the ribbon? I'm thinking of a 6-amp set up

Thanks.

[udailey]

Hi GLT,
This situation I believe is addressed, if I understand what you are asking, in the original thread.
My "audiophile" LM3886 approach
Just try the search function.
Uriah

[bhm]

please sign me up for a dual mono version. thanks

Blair

[Floric]

Hi, this is a kind of dumb question, but was not able to find examples of this amp with an active crossover configuration, so, are these suitable for a bi-amp, tri-amp configuration? I want to two amps to drive two woofers, each with a simple second order low pass filter at 1000 Hz, and one amp with a simple first order high pass for the ribbon (this is just a duplication of the passive crossover). Also is the DC protection circuit good enough to leave the ribbon unprotected (with a cap) and feed the amp straight to the ribbon? I'm thinking of a 6-amp set up

I used to run them actively (four channels of "Penasas") they worked like a charm with 2nd order active filters. By the time I decided to use something more powerful for the bass. But for the mid/hights I still use my ones and I am glad with them. The DC-protection works very well.

Best regards

Flo

[udailey]

bacood_2000 x2
warp_foo x2
Coreyk78 x2
SRMcGee x2
troystg x4
samsagaz x2
widman x2
billyk x2
korben69 x2
tube-arama x2
bandol83 x2
erikdebier x2
Joshua Adams x6
helfred x2
vglaso x2
Dxvideo x2
nvrgdenuf x4
Mindcrime x2
ben_lesmana x2
Daveze x2
Fredlock x2
argofanatic x2
GiovanniM x2
bhm x2
========
Minimum 56 requested
Some have mentioned ordering more but were not sure yet. If they did we would be at 62.

Uriah

[Tony X]

Hi there,

I'm also keen for a Stereo unit would need some answers to the following:


My setup is:

Sony DVP-NS900V (used only as a CD player)
T-Amp modified
97db 10inch full ranges drivers (Audio Super Nivana)

I do not use a turn-table

I am in general very pleased with this but just want a bit more bass.

Having read a lot of positive reports of the LM 3875 Gainclone from Nick Whetstone (et al) I was intending to buy one of Peter Daniel's Chipamp kits to replace my modified T-Amp. Now it seems that the AudioSector have dropped the Chipamp in favour of an LM3886 based unit.

That's when I stumbled on your proposal.

Would you recommend your proposal used as an integrated stereo amplifier with no pre-amp?
What pot configuration would you then recommend?
What rating torroidal (240v supply) is recommended?

Hoping you get all the support needed.

[udailey]

Would you recommend your proposal used as an integrated stereo amplifier with no pre-amp?
What pot configuration would you then recommend?
What rating torroidal (240v supply) is recommended?

Hoping you get all the support needed.

AudioSector has not dropped any chipamp from what I understand. AudioSector has always done the LM3875 and ChipAmp has always done the LM3886 or maybe thats reversed but either way they are both chipamps.
Congrats on your AN10's. I have AN12's and LOVE them. They are fantastic speakers. I drive them with a LM3886. I am right now building a subwoofer so that probably answers your bass question. I have done a frequency test on them and they play down to 11hz even though you cant hear it at that frequency and the specs show it should not the cone is vibrating furiously at 11Hz. It plays 20Hz with gusto, but for some reason, and maybe its the cab, I still feel as if I need more bass.
So in with a subwoofer and I will build a preamp that has bass/mid/treble adjustments. I would advise you to buy G. Randy Slone's book on building amps.... The Audiophiles Project Sourcebook. Great preamps in there. Really easy to build.
You can for sure run this amp without a pre. Just a passive pre by way of a pot. The pot should be from about 20-25Kohm. The output from your CDP comes into the pot and out to the amp. Thats it. Real easy. You can goof it up of course but there are only three choices for attaching the wires so on one of your tries you will get it right for sure. Or just google potentiometer hook up.
Look for a toroid of minimum 200VA maybe max of 300-400VA preferably about 250VA. You could use one of maybe 150VA for each channel if you wanted dual power supplies. Anything around that 200-400VA will obviously work well. You need the transformer to output 20-25V with 24V preferred.
This is one of the best if not the very best implementation of the LM3886 chip. Yes I would recommend it for your system. HOWEVER if you want more bass you have to attenuate it or get a subwoofer. Meaning a preamp with controls or a powered sub. This chip is amplifying what is sent to it. So if you dont send it bass its not going to make any and if the bass on the CD isnt enough you have to have some preamp asking the amp for more bass.
Uriah

[madisonears]

Uriah,

I don't see my name on your list. I am interested in dual mono.

There is no need to supply boutique components in these kits. I believe Mauro was pretty selective and thoroughly evaluated the components he chose.

Of course these kits require some level of diy skill. The original thread, however, contains a lot of conflicting information, arguements regarding implementation, circuit changes, power supply configuration, component selection, etc. I was wondering if you or anyone else has distilled down all this hubbub into a reasonable document that offers all the valuable pearls and eliminates the stupid speculation and idle comments from those who don't really know what they're writing about.

Peace,
Tom E