Biamping SEAS Odin Mk3 with Gainclones - to bridge, or not...

[Monroe]

I'm just finishing up a SEAS Odin Mk3 (so excited! my first 'good' speaker set!).

Right now, my only amp is a 10 year old 100 watt sony receiver - not terrible, but not up to the challenge of driving the 4 ohm Odin properly.

SO: I'm thinking of building a gainclone amp to bi-amp the Odin. (i.e. 4 channels).

The appropriate chip seems like the LM 3886 - 68 watts into 4 ohms.

That would make around 130 watts per channel, which should be sufficient - correct? (4 of them)

Would I better off trying to used bridged pairs instead (i.e. 4 pairs of 3886's driving the speakers [biamped])? The speakers are rated 200 watts (its a SEAS Excel MTM kit) so I dont think that would be overkill - I'm just not sure if using pairs (bridged) is needed or not.

Or, if another approach entirely would be better...


Thanks!

[Variac]

A bridged amp is going to be even more touchy about the 4 ohm impedence, AFAIK


Another option would be using the current chip amp kit with the 3875. Apparently it works fine with just one per channel.

OK , so you want more headroom? Then 2 per channel should be fine, one for the tweeter 1 for woofers - even though the chip is rated at 50w/ch

But how about this:

Amplify each woofer separately with an amp. And the tweeter with it's own.
That would be 3 amps per channel, and into 8 ohms.
Because of the different impedence the woofer crossover would change,, but in a easily calculable manner (but not by me!!! ) and you would need 2 per channel


This ideawould be an especially good approach if you are planning to use an active crossover. (With multiple amps you should!!- it makes the approach even better! and more efficient!!!

But can you get the active crossover adjusted right?

[Monroe]

Originally posted by Variac

Another option would be using the current chip amp kit with the 3875. Apparently it works fine with just one per channel.

Hmm? What current chip amp kit? Right now I only have an old receiver, and the speakers. No chip amp kit...

What's the advantage of the 3875, over the 3886? It seems weaker into 4 ohms...

But how about this:

Amplify each woofer separately with an amp. And the tweeter with it's own.
That would be 3 amps per channel, and into 8 ohms.
Because of the different impedence the woofer crossover would change,, but in a easily calculable manner (but not by me!!! ) and you would need 2 per channel

It sounds like an ok idea, but the crossover's are fixed, i dont want to order new parts and start messing around with that. Also, I still want to be able to use the speakers with just a regular amp (i.e. if i change the setup, give or sell them to someone else, etc.)... so i think that's out...

[Variac]

There is a kit available that a person on this forum has put together . It is cheap and good, but not available again for another month.


Group order of non-inverted LM3875 pc boards? Anyone interested?

Otherwise you are right, your chip puts out more power.
the 3875 has a bit better reputation for sound, but that may or may not be true.

A lot of people keep their crossovers out of the speaker- less vibrations, and easier to modify. Then you need another small box though...

Are you going to add a second set of terminals to biamp?

[BrianGT]

Originally posted by Monroe
I'm just finishing up a SEAS Odin Mk3 (so excited! my first 'good' speaker set!).

.
.
.

Or, if another approach entirely would be better...

Great choice on the speakers. I am using the Seas Thor TL kit.

I am running them with a single LM3875 per channel, and it is more than enough to drive them. The 4 ohm load is fine with my 2x24vac transformer 320va.

--
Brian

[Monroe]

Originally posted by BrianGT


Great choice on the speakers. I am using the Seas Thor TL kit.

I am running them with a single LM3875 per channel, and it is more than enough to drive them. The 4 ohm load is fine with my 2x24vac transformer 320va.

--
Brian

Took a look at your gallery - nice job on those speakers! I'm just using mdf (no solid wood front, unfortunately).

http://www.dame-electric.com/projects-odin.htm

My speakers arnt finished; should be ready in a few weeks.

How does your Thor sound? What's the tonality like? What sort of music do you generall play through it?

Do they go loud enough with the 3875? Maybe my 100 wpc receiver will be up to the job after all...

-Dave

[BrianGT]

Originally posted by Monroe



Took a look at your gallery - nice job on those speakers! I'm just using mdf (no solid wood front, unfortunately).

http://www.dame-electric.com/projects-odin.htm

My speakers arnt finished; should be ready in a few weeks.

How does your Thor sound? What's the tonality like? What sort of music do you generall play through it?

Do they go loud enough with the 3875? Maybe my 100 wpc receiver will be up to the job after all...

-Dave

Seriously give the LM3875 a try.. it got loud enough to make my ears hurt the next day! (no recommended)

(at school in lab with my cdpro2, cranked up really loud)

--
Brian

[Variac]

Dave,
I think it is a mistake to look at this as a power issue.
The 3875 and the 3886 aren't going to be very different in volume, you really have to double the power to make a significant difference.

The main point is that a 3875 gainclone is almost undoubtedly going to sound better than your old receiver. And Brian says it does the job-4 ohms and all.

[S.C]

Can it be a sub woofer amp?