Combination of chipamps

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Hello all,

Before I used the name Rallyecoupe, but this registratoin did not give me the opportunity to post (strange), so I made a new account.

Now, to my question:

I am planning to build a chipamp for my Dayton Seventeen speakers. I want to Bi-Amp, so I need 2 Amps for each channel.

For the bass I want to use a dual-mono LM4780 kit, but for High (it´s a 2-way speaker) I am not quite sure which amp to use. Is there a difference in sound between the LM3875 and LM3886?
I want to order the amps at audiosector.com, but here I can´t order the LM3886 kit. Why I prefer this amp? Because I think this one sounds most like the LM4780 (which are 2 LM3886 amps in one housing). At audiosector.com I can only order the LM3875.

The other option is to use 1 LM4780 for both High-channels. At this point I don´t know if the channel separation is as good as with 2 separated amps. For the supply this all doesn´t matter, because I have 2 500VA toroids for the 2 supplies. :D

So, what would you do and, more important, why?
LM4780 + LM3886
LM4780 + LM3875
LM4780 + ½ LM4780
LM4780 + LM4780 (maybe too much power on the tweeter)

The passive filter will be in the speakers, so I don´t use an active crossover.

Kind regards,
Mischa
 
I prefer the sound of the LM3875 to that of the LM3886! However, I am currently using LM3875 for mid/tweeters, and LM3886 for woofers and it sounds fine. ie, I can't say that the woofers sound 'different' to the mid/tweeters!

So I think you will be fine with the combination of LM4780 + LM3875!
 
Netlist said:

Well, here I asked what I needed beside the kit, now I asked what kits would be best to use. At this moment I allready have the toroids, as you can see in my first post. :D I have to admit that I haven´t read my old post. :angel:

@Nuuk:
What´s the difference in sound? You say you prefer the sound of the LM3875 to that of the LM3886. Why?

Kind regards,
Mischa
 
So you say the 3875 is the better sounding one?

If I wouldn't miss the extra power of the 3886 (even if it's only 18W), the choice is easy, then I'll go for the 3875 and I can order everything in one place.

Does someone else have to add something to this?

Regards,
Mischa
 
Nuuk said:
Just how much is the '"high" part of your speaker going to need? :att'n:


I really have no idea. I hoperd you could tell me. On the other side, the power supply is heavy enough to use 2 LM4780 amps for each channel, but I wouldn´t know how large the heatsink should be if I did this. The difference in price is not that much, as I have seen.

Mischa
 
I am going to build the Seventeen:

Specs Seventeen:
- Measurements (HxWxT): 41 x 23 x 31 cm
- Impedance: 8 Ohm
- sensitivity: 85 dB
- (-8dB): 40 - 25000 Hz
- Crossoverfrequence: 2100 Hz
- Bassreflex 18 L

Drivers:
Bass: - Dayton 295-350
High: - Dayton 275-100

The filter is built with High End components.

The complete stuff is on this site (unfortunately in German)

http://www.lautsprechershop.de/hifi/seventeen.htm

Kind regards,
Mischa
 
It's not really about how loud they can play. It's about the sound quality at normal listening levels. When you go back through the great Gainclone debate, about whether they are good amplifiers or not, those that have said yes, have nearly always heard them through efficient speakers where they don't have to work as hard.

Lower efficiency speakers call for more power and that is when people start adding the larger caps that seem to rob the GC of some of its magic.

Obviously if you already have speakers that is what you are stuck with. But if you want to build a GC, and are then purchasing speakers, it surely makes sense to get the most efficient you can! ;)
 
Nordic said:
I feel the same as Nuuk, its hard to put my finger on it, but I also found the LM3875 easier on the ear...
Also its much easier to work with, when you cut off the NC pins there is only 5 pins to work with, you can even fit that onto veroboard, with a little bending...
No mute pin to contend with etc...

I have built a biamp. Originally planning use a mix of chips. Until the extra leg connections of the 3886 annoyed me to screaming point, started short circuiting, and eventually snapped off!!
I heard no obvious difference in the chips, so ordered new 3875's for completing amp. I totally agree with nordik - 3875's easier to work with.
If you are using a kit board - its easier to connect, so extra power output would be a bigger factor than the (IMO) insignificant difference in sound.
 
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