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Old 10th September 2003, 10:32 PM   #21
Elkaid is offline Elkaid  Canada
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Default Yeah but....

Re-bonjour,

Quote:
Posted by Kuei Yang Wang
The result is INVARIABLY a drasitic decrease in sound quality. Just build the same discrete amplifier circuit with one pair of output transistors or with a huge bank of them.
Everything is relative
Would you say that Jeff Rowland's amplifiers (Bridge + parallel I suppose) or any other using parallel devices sounds bad ?

By the way, thank you. I know that you and many other here are trying to give hints to achieve the best possible results and trust me, it is greatly appreciated.

Quote:
Posted by Kuei Yang Wang
but if you have such incompetently designed speakers that their impedance falls much below 3 Ohm.
I have a simple pair of Energy Pro 3.5 loudspeakers... I know that they're no really difficult load but I wish to experiment a bit.

And here's my latest attempt using OPA627 with +/- 15V for the Buffer

Continue to send in your comments, they're really appreciated !
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Old 11th September 2003, 12:18 AM   #22
Elkaid is offline Elkaid  Canada
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Well, I just found out this schematic from Nuuk.
Looks interesting !
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Old 11th September 2003, 01:32 AM   #23
JoeBob is offline JoeBob  Canada
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I've been toying with a buffer setup simmilar to Nuuk's schematic you posted.

In the end I ended up changing the OPA627 for an EL2001 buffer, I found it sounded more clean.

I don't know what buffer parts are in production, but you might want to give one a try in the place of the OPA.
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Old 11th September 2003, 12:28 PM   #24
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Default Re: Yeah but....

Konnichiwa,

Quote:
Originally posted by Elkaid

Everything is relative
Would you say that Jeff Rowland's amplifiers (Bridge + parallel I suppose) or any other using parallel devices sounds bad ?
Compared to otherwise equal designs accepting lower power and using single devices - ABSOLUTELY, assuming the extra power is not essential to have.

Quote:
Originally posted by Elkaid

I have a simple pair of Energy Pro 3.5 loudspeakers... I know that they're no really difficult load but I wish to experiment a bit.
I would not know them from Adam....

Looked them up. You know what. IF I WAS YOU and wanted to get more dynamics from them and better sound as a standard gainclone will do I would drive the woofer from a bridged pair of LM3886 with an 24V + 24V Transformer and the tweeter from a single LM3875 Chip.... The 3886 can provide more current than the 3875 and thus a Bridged pair will have more power into the same load.

Or use LM3875 all around and keep the Transformer to 18V + 18V, still plenty of power for the woofer.

By all means fit a buffer and use a low value, high performance coupling cap for the Tweeter section. Using 47nF should be fine, you can get a good Film & Foil Polypropylene Cap for that. Add another Op-Amp working as unity gain inverter after your buffer to form the Bridge for the Woofer.

This bi-amplifies the speaker with up to 45V undistorted short peaks on the woofer, equivalent to around 250WPC conventional Amplifiers in maximum loudness....

You would have a simple "biamplifier" using gainclone technology which IMHO would be MILES ahead of what you are proposing.

BWTFDIK.

Quote:
Originally posted by Elkaid

And here's my latest attempt using OPA627 with +/- 15V for the Buffer
Well, if you Invoke Jeff Rowland you should at least have a look at his designs and at how he minimises the problems from paralleling devices. I see non of these in your design.

The best use with your speakers would be to split the outputs up and use this Bi-Amplifier. You can try it yourself. Build as drawn but fit two pairs of Output Binding posts, one for each chip. Then you can add a wirebridge or remove it to switch between "Biamp" and "parallel". Let's see what you hear.....

Sayonara
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Old 11th September 2003, 03:00 PM   #25
JoeBob is offline JoeBob  Canada
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I second Thorsten's reccomendation to biamp, it really is very easily done with "gainclones". A 2nd amp is basically just as easy to do as paralleling the devices in this case.
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Old 11th September 2003, 03:11 PM   #26
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A friend of mine tried bi-amping (one stereo amp per channel) and he was really impressed. According to him it was much better than using a single GC.
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Old 14th September 2003, 02:59 PM   #27
Elkaid is offline Elkaid  Canada
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Merci !

Quote:
Posted by Kuei Yang Wang
Well, if you Invoke Jeff Rowland you should at least have a look at his designs and at how he minimises the problems from paralleling devices. I see non of these in your design.
You seems to forget that I'm an amateur and I'm still MILES away before being able to criticize other's design. Moreover, the first thing would be to actually have access at Jeff's schematics.

Quote:
Posted by Kuei Yang Wang
I would not know them from Adam....
Here's a quick link : http://www.energyloudspeakers.com/so...s_brochure.pdf


I never thought about GC biamping and it looks like a great idea ! Looks like I'll have a lot of work for the next weeks.

Thank you and have a nice day !
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Old 14th September 2003, 04:36 PM   #28
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Quote:
never thought about GC biamping and it looks like a great idea
IT IS......4 small monoblocks - go for it...!
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Old 15th September 2003, 08:24 AM   #29
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Konnichiwa,

Quote:
Originally posted by Elkaid

You seems to forget that I'm an amateur and I'm still MILES away before being able to criticize other's design. Moreover, the first thing would be to actually have access at Jeff's schematics.
Well, you shouldn't need them. There where several large size, high quality pictures of the insides of his amp's posted here.... These should suffice.

IF THEY DON'T suffice, maybe it would be worthwhile to simply build already established designs and lear to walk before trying to run?

Quote:
Originally posted by Elkaid

I never thought about GC biamping and it looks like a great idea ! Looks like I'll have a lot of work for the next weeks.
I would say go for it. The next stop could then be current drive on the tweeter and mixed drive on the woofer plus active X-Overs... ;-)

Sayonara
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Old 15th September 2003, 12:40 PM   #30
Elkaid is offline Elkaid  Canada
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Thank you very much for your precious help.

Have a nice day !
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