BOSC - HiFi Monoblock Class-D Amp

[orchardaudio]

Currently Under Development

Preliminary Specifications:

• Gain: 16.8dB or 6.92 (For 8 and 6Ω speakers)
• Gain: 13.8dB or 4.89 (For 4 and 3Ω speakers)
• Signal to Noise Ratio (SNR): 121dB (A-weighted)
• Total Harmonic Distortion (THD): <0.0003% (-110dB) @ 7W
• Frequency Response: DC - 60kHz
• Sensitivity: 2.5Vin for 37.5W
• Input Impedance: 5kΩ fully balanced for 8Ω amp
• Input Impedance: 7.1kΩ fully balance for 4Ω amp
• Output Power: 150W
• Damping Factor: >400 @ 1kHz
• Size: 5.5" (14cm) x 4.8" (12.2cm) x 1.9" (4.8cm)

THD vs Power Plot 8 ohm load (Preliminary):

Follow this thread for updates, you can also subscribe to the mailing list on the website here: https://orchardaudio.com/bosc

 

[Daverz]

Ouch, that input impedance is really low. I do like the lower gain. An exciting development.

 

[orchardaudio]

Ouch, that input impedance is really low. I do like the lower gain. An exciting development.

I am not sure what you mean by output impedance, I did not specify it anywhere, I have yet to runt those tests

 

[solderdude]

I sure hope it has DC protection on its output ... being DC to 40kHz and all.

@Daverz talks about the input impedance being 5k (for balanced) as noted in the specs.

 

[orchardaudio]

@Daverz talks about the input impedance being 5k (for balanced) as noted in the specs.

Keeping it low helps with better noise performance.

 

[orchardaudio]

If you are in the NJ area stop by and check out both the PecanPi DAC and BOSC Amp at a demo on July 6th.

You can RSVP here:
https://www.facebook.com/events/348651915800038/

If you do not have Facebook just send me a message and I will get you the details.

 

[orchardaudio]

Sign up to get updates and receive special early bird pricing on the amazing BOSC™ monoblock amp:
https://www.indiegogo.com/projects/bosc-hifi-monoblock-class-d-amp/coming_soon

 

[orchardaudio]

If you are in the NJ area stop by and check out both the PecanPi DAC and BOSC Amp at a demo on July 6th.

You can RSVP here:
https://www.facebook.com/events/348651915800038/

If you do not have Facebook just send me a message and I will get you the details.

Demo this weekend in Succasunna, NJ if you want to attend please send me a message.

 

[orchardaudio]

Doing a lot of tweaking and testing of the BOSC design this weekend and was able to figure out a way to get a significant improvement in THD at higher power levels.

At about ~7W into 8 ohm I am now at -110dB THD (0.0003%)

 

[orchardaudio]

If you are really interested in this product and would like to be one of the first people to get it at a reduced price, reserve now for $1. Only 55 spots available:
https://orchardaudio.com/shop?olsPage=products/bsc-mplfr

 

[pos]

What is the price of the amp, including the power supply?

 

[orchardaudio]

It will be around $500 per amp, or $1000 per pair. With power supply included.

 

[Icboschert]

Is it 4 ohm rated?

 

[orchardaudio]

Is it 4 ohm rated?

There will be two versions, the 4 ohm version will have 1.41 times less gain, so that power stays at 150W.

 

[orchardaudio]

BOSC Pricing:

• Indiegogo VIP: $999 for two (2) BOSC Amps - Register Now only 55 spot available
  • 33% Savings from an MSRP of $1499
• Indiegogo Early Bird: $1099 for two (2) BOSC Amps - limited availability
  • 26% Savings from an MSRP of $1499
• Indiegogo Regular Price: $1199 for two (2) BOSC Amps
  • 20% Savings from an MSRP of $1499

BOSC specification have been updated after the latest round of testing and can be found here:
https://orchardaudio.com/bosc

 

[orchardaudio]

Damping Factor: >400 @ 1kHz

Frequency Response: DC - 60kHz

Updated specs in first post.

 

[DonH56]

Seems like fairly low gain?

 

[LightninBoy]

Why are the speaker terminals so close together?

 

[Daverz]

Seems like fairly low gain?

The gain is about right for a 4V balanced DAC output.

But 5k Ohm is a very low input impedance. Even most semi-pro gear has a 10k Ohm input impedance.

 

[orchardaudio]

Why are the speaker terminals so close together?

They are the standard 0.75'' apart, they just look close in the picture from the angle photo was taken.