Help! Building an amplifier to run B&W 800D

[harrisni]

Hi,

I want to build an amplifier to run a pair of B&W 800D speakers.

Most people who I know that have these speakers run the 2x Classe CA-M400 (2x400W 8ohms)

models
(balanced inputs) CA-M400
voltage gain 29.1dB
bandwidth 155kHz (-3dB)
22kHz (-0.1dB)
phase < -10° (22kHz)
sensitivity 2.0Vrms
power/channel (continuous)
(120VAC line, 1kHz signal regulated to 1% THD + noise into resistive load, all channels driven)
load (resistive)
8Ù 400W
4Ù 800W
THD + noise
(unweighted, 10Hz - 500kHz bandwidth, 1Vrms/1kHz input)
load (resistive)
none 0.001%
8Ù 0.003%
4Ù 0.005%
noise FFT noise floor peaks all below –95dBV
(with terminated inputs)
S/N ratio (relative to 1kHz sine wave full level output into 8Ù)
112dB
rated power consumption 480W

http://www.classeaudio.com/delta/specs/cam400.htm


I would like to build something like this, Ive been talking to Anthony from AA and he has a new NX model coming out soon which is close in power think its around 300W 8ohms. Anyone know of something with same or better specifications?

Cheers

Nick

[lucpes]

Originally posted by harrisni
Hi,

I want to build an amplifier to run a pair of B&W 800D speakers.

Most people who I know that have these speakers run the 2x Classe CA-M400 (2x400W 8ohms)

I would like to build something like this, Ive been talking to Anthony from AA and he has a new NX model coming out soon which is close in power think its around 300W 8ohms. Anyone know of something with same or better specifications?

Cheers

Nick

Hi, you might want to take a look in the class D forum, I'd recommend buying a pair of Hypex's UcD700 to accomplish what you want (power, control and overall top notch sound).

[HiFiddle]

I would recommend Greg's GB300D as a contender here -

http://www.diyhifi.org/amplifierguru/guru_002.htm

and it's made in Australia just north of you in Qld! It'd probably put that Classe to shame if built well.

[Greg Erskine]

hi harrisni,

I think you should post the specs of your speakers, then people can advise you what amp they think would be suitable. Also a few details of your room.

At the moment, people are just giving options close to the Classe CA-M400 specs, which may or may not be optimal.

regards

[harrisni]

Technical Specifications : 800D

Description 3-way vented-box system
Dimensions Height: 1180mm (46.5 in) (not including feet)
Width: 450mm (17.7 in)
Depth: 645mm (25.4 in)

Net Weight 125kg (275 lb)
Freq. Response 32Hz - 28kHz ±3dB on reference axis
Freq. Range -6dB at 25Hz and 33kHz
Sensitivity 90dB spl (2.83V, 1m)
Normal Impedance 8 ohms (minimum 3.1 ohms)
Power Handling 50W - 1000W into 8 ohms on unclipped programme
Drive Units Unit 1: 1x 25mm (1 in) diamond dome high-frequency
Unit 2: 1x 150mm (6 in) woven Kevlar® cone FST midrange
Unit 3: 2x 250mm (10 in) Rohacell® cone bass

Finish Cabinet: Real wood veneers of Cherrywood, Rosenut or Black Ash
Grille: Black cloth
Dispersion Description: Within 2dB of reference response
Horizontal: over 60º arc
Vertical: over 10º arc

Harmonic Distortion 2nd and 3rd harmonics (90dB, 1m)
<1% 45Hz - 100kHz
<0.5% 80Hz - 100kHz
Crossover Frequency 350Hz, 4kHz
Max. Recommended Cable Impedance 0.1 ohms


And


Technical Specifications : HTM3S

Description 3-way closed-box system
Dimensions Height: 320mm (12.6 in)
Width: 783mm (30.8 in)
Depth: 316mm (12.4 in)

Net Weight 28kg (62 lb)
Freq. Response 42Hz - 22kHz ±3dB on reference axis
Freq. Range -6dB at 35Hz and 50kHz
Sensitivity 90dB spl (2.83V, 1m)
Normal Impedance 8 ohms (minimum 3.2 ohms)
Power Handling 50W - 250W into 8 ohms on unclipped programme
Drive Units Unit 1: 1x 25mm (1 in) aluminium dome high-frequency
Unit 2: 1x 150mm (6 in) woven Kevlar® cone FST midrange
Unit 3: 2x 165mm (6.5 in) Rohacell® cone bass

Finish Cabinet: Real wood veneers of Cherrywood, Rosenut or Black Ash
Grille: Black cloth
Dispersion Description: Within 2dB of reference response
Horizontal: over 60º arc
Vertical: over 10º arc

Harmonic Distortion 2nd and 3rd harmonics (90dB, 1m)
<1% 100Hz - 22kHz
<0.5% 120Hz - 20kHz
Crossover Frequency 350Hz, 4kHz
Max. Recommended Cable Impedance 0.1 ohms


and

Technical Specifications : 803S

Description 3-way vented-box system
Dimensions Height: 1063mm (41.9 in) (not including feet)
Width: 291mm (11.5 in)
Depth: 433mm (17 in)

Net Weight 41kg (90 lb)
Freq. Response 35Hz - 22kHz ±3dB on reference axis
Freq. Range -6dB at 28Hz and 50kHz
Sensitivity 90dB spl (2.83V, 1m)
Normal Impedance 8 ohms (minimum 3.0 ohms)
Power Handling 50W - 250W into 8 ohms on unclipped programme
Drive Units Unit 1: 1x 25mm (1 in) aluminium dome high-frequency
Unit 2: 1x 150mm (6 in) woven Kevlar® cone FST midrange
Unit 3: 2x 180mm (7 in) Rohacell® cone bass

Finish Cabinet: Real wood veneers of Cherrywood, Rosenut or Black Ash
Grille: Black cloth
Dispersion Description: Within 2dB of reference response
Horizontal: over 60º arc
Vertical: over 10º arc

Harmonic Distortion 2nd and 3rd harmonics (90dB, 1m)
<1% 70Hz - 22kHz
<0.5% 80Hz - 20kHz
Crossover Frequency 350Hz, 4kHz
Max. Recommended Cable Impedance 0.1 ohms

[AndrewT]

Hi,
the 3.1r indicates that the 800d is a 4 to 8ohms speaker even though B&W rate it at 8ohm nominal.

This demands that the amplifier be rated for use into 4ohm loads.

Ampguru's SKA gb300 could be used to it's design limit of 300W into 6ohm by selecting an appropriate transformer voltage and I think the designer would confirm it suitable for domestic use into 4 to 8ohm speakers. This amp will put in excess of 400W into 4ohm but only for short term duty. A bigger heatsink gives more leaway.

800d is rated @ 90db/2.83V so 100W is equivalent to 110db
and 200W should give a peak of 116db (peak SPL=+3db on continuous)
The 400W8r/800W4r will manage an extra 3db. Do you need that?

If so then use a "quasi" (with no name yet) for the bass drivers and another for the mid and treble.

[EUVL]

If I could afford the 800D, I would get myself a pair of Pass XA200 (200W Class A), or use active crossover and run the tweeter with a (e.g.Linsley Hood) 15W Class A, the mid-freq with a 100W Class A (e.g. XA100), and the bass with 200W chip amp.

Or you might want to try the GEM from Graham Maynard (I hope I spell the last name correctly).

Incredible quality amplifier by Graham, prepare your ears for it


Patrick

[harrisni]

Originally posted by AndrewT
Hi,
the 3.1r indicates that the 800d is a 4 to 8ohms speaker even though B&W rate it at 8ohm nominal.

This demands that the amplifier be rated for use into 4ohm loads.

Ampguru's SKA gb300 could be used to it's design limit of 300W into 6ohm by selecting an appropriate transformer voltage and I think the designer would confirm it suitable for domestic use into 4 to 8ohm speakers. This amp will put in excess of 400W into 4ohm but only for short term duty. A bigger heatsink gives more leaway.

800d is rated @ 90db/2.83V so 100W is equivalent to 110db
and 200W should give a peak of 116db (peak SPL=+3db on continuous)
The 400W8r/800W4r will manage an extra 3db. Do you need that?

If so then use a "quasi" (with no name yet) for the bass drivers and another for the mid and treble.

So your saying if I used a 100watt 8ohm/200watt 4ohm amp it would run it to the specifications?

[AndrewT]

Hi,
yes.
Just not quite as loud.
100W will lose another 3db.

One major caveat when using lower powered amplifiers driven hard into apparently robust speakers.

An amp driven into clipping produces an enormous amount of distortion and by definition ALL of this didtortion is high frequency.

The passive crossover diverts most of this high frequency clipping distortion to the delicate treble speaker and overheats it. DEAD as a dodo.

Listen to the effect of turning up the volume and take care of your tweeters and your ears.

[ANALOG GUY]

Gamut D200 clone !!!

I think it can help you, not class-a but stereophile class-a reccomended he he

Thanks
analog guy