Need help with my bi-amp system

[benproiii]

Im trying to design a bi-amp system or my living room. I made the active crossover (ESP Project 81) which is set to 130Hz i have SEAS Prestige 27TBCD, SEAS Prestige ER18RNX for the high pass and the 1 Dayton 15" Reference Subwoofer on the low pass. I am just confused what amp to build that will sound the best for each.

I like the DX Precision I amp for my subwoofer because it's said to produce a lot of power and have good bass response. is there any other amps that will work better for this application?

For the mid/highs i though of building the DX Precision I again but running from regulated 45+/- and using 2 output pairs instead of three to reduce power output. Is there any other amps that have better sounding highs/mid's that are not that hard to build? How does the normal dx amps highs/mid's sound compared to the DX Precision I?

 

[digits]

I'd ignore the standard dx for hi fedility purposes, very boomy bass more suitable for a BBQ and beer than fine listening. The DX HRII has fine mids and trebles.

 

[benproiii]

The HRII has better sounding mid/treble than Precision I

 

[Tekko]

Maybe my circuit could be something ? I'm listening to it as i type this.

http://i.imgur.com/sIXVz.png

 

[AndrewT]

Tek,
why have you shorted out R17?

 

[Tekko]

Its only a simulation thing, that resistor doesent actually exist in the actual amp.

Anyways im doing open loop simulations at this thing atm and its virtually flat from 1Hz to 1MHz, phase is pretty flat too, i reckon that makes this a pretty good design.

 

[digits]

I think the Precision beats any of the older DX amps including the HRII, but at a cost in parts, heatsinks, transformers and electricity consumption. If money is no problem, I'd use the same amps from bottom to top, so that things stay "voiced" the same, gain stays the same, etc...

 

[benproiii]

If i'm going to build the precision I 3 times i need to make it simpler.
Will these modification's to the circuit make still it stable/sound good?

Do the vas/driver transistor's need a heat sink? (in my experience the vas/drivers even in high power amps don't get that hot)

I was thinking of running the high/mid amp off a linear regulated 50+/- and it having 2 output pairs and the subwoofer amp run off unregulated 65+/-

What is the max safe operating voltage to power the amp's off of with my modifications? (The sub is 4 ohms, highs/mid 8 ohms)

 

[digits]

I ran mine on 70VDC. tiny screwon sinks on the TO220's, not as a safety measure but rather as an attempt at temperature stability through transients.

 

[AndrewT]

Do the vas/driver transistor's need a heat sink? (in my experience the vas/drivers even in high power amps don't get that hot)

you, the builder, have complete control of that.
Either build it exactly to match a successful design or re-design it to suit your choice of current, voltage and heatsinking (if any).

 

[Tekko]

I've never used anything bigger than a 2N5401 as VAS and never had a problem with temperature, but thats just me.

 

[sreten]

Hi,

Zaph|Audio - ZA-SR71, in your case a smaller depth sealed version.

Personally I'd consider class d for the sub, any decent amplifier for the mains.

rgds, sreten.

 

[benproiii]

So in your best opinion will my circuit be stable

 

[benproiii]

So in your best opinion will my circuit be stable

BUMP

 

[AndrewT]

Hi,
some of your resistor value choices seem unconventional.
Have you looked at current flows yet?

But it may work. How do you find out?

 

[Tekko]

Why cant ppl built the circuits with the values given by the author ? Why do ppl have to change values ? Is it to make the design slightly more their own or atleast impose that feeling ?

 

[lineup]

People are creative. They want to create and make.
To feel they have achieved something. Done some change.
Not all. But many people.

 

[benproiii]

I changed the resistor values because those are the only values i have of 1% metal film resistors.

Will the change cause any negative side effects?

 

[digits]

....and there is that, fitting designs to what is on hand, we even do it when cooking.