[GLF]

The test boxes are 18" tall, 8.5" wide and 14.5" deep.

Any chance at an option that has less depth? The height and width are big desk friendly but that depth would eat up a lot of space!

[Danny Richie]

Any chance at an option that has less depth? The height and width are big desk friendly but that depth would eat up a lot of space!

Rule of thumb is the width can be no more than 2/3rds of the depth.

Shorting this one will alter the tweeters rear, and to some degree, the front output. I'd have to see what effect it would have by shortening it some.

[2bigears]

   ETA on these ready to 🐝 shipped ? I need one or two pair,,,,

[cody69]

Danny,
I've been wondering what you've been working on and where you've been applying your magic.
These are quite interesting and anxious to hear more as you work out the details and finalize the design.

[grimace]

Very cool and I second the idea about making a powered version.  That would be great.

[Danny Richie]

Very cool and I second the idea about making a powered version.  That would be great.

Yeah, I am thinking something like the Folsom amp with external power supply and a single RCA and balanced input. The power supply can then be a linear one or a battery plugging in with a Neutrik connector. It would need a little more power though.

[Danny Richie]

  ETA on these ready to 🐝 shipped ? I need one or two pair,,,,

It's time for me to build out a pair, listen to them and tweak them.

[2bigears]

  ballpark $$ ,,,, I gave the little elac monitors a try. Sent them back. Cheap is cheap I guess.  If you can keep the cost under control you will sell lots of these I think. Peeps really are on a budget these days.  But these little gems look cool.   

[Folsom]

I may be able to customize a PCB a little for these. The hardest part is really fact that the chip must be angled 90* from PCB. Maybe I can come up with a way around that some day.

[Danny Richie]

I may be able to customize a PCB a little for these. The hardest part is really fact that the chip must be angled 90* from PCB. Maybe I can come up with a way around that some day.

There is plenty of room in the box for that little amp. My only concern is power. I'd like to see a little more power for it as it only has 89db sensitivity.

[HT cOz]

There is plenty of room in the box for that little amp. My only concern is power. I'd like to see a little more power for it as it only has 89db sensitivity.

TPA3255

[WC]

TPA3255

That should work. Planning on using the TPA3255 amps to power my subs.

[Folsom]

The TDA7297 can never have more power unfortunately.

[maty]

Very good project Danny.

Closed speaker, without bass-reflex.

-3 dB: 75 Hz. About 89 dB/W/m.

Powered?

http://www.doctorproaudio.com/doctor/calculadores_en.htm#calc_spl

Calculators / Audio / Acoustics / SPL



With SPL continuous of 80 dB (loud sound, usually I listen about 65 dB) and very good recordings with high DR (dynamic range) of 15 dB (peak power) we need 95 dB.

This calcs with near field -> in phase: +3 dB -> 94.2 + 3 = 97.2 dB (15 Watts, 3 m).

The tweeter better with a class A or AB amp than cheap with old class D technology I think.

[maty]

Deleted by maty.

[maty]

Closed speakers at 75 Hz (3 dB). If the impedance is near 8 Ohms, maybe the LM3886 (class AB).

[HAL]

The TPA3250 is a stereo amp, where the LM3886 is mono, so you would need two LM3886 for the powered monitor.  Lots of heatsink on the cabinet back for the LM3886's.

The TPA3255 is a lot higher power, 315W max stereo, so really overkill for the minimonitor.

Both the TPA3250 and LM3886 can be used with balanced inputs for studio use without problems.  I used the older LM3875 with balanced inputs with very good results.  The only thing might be startup transients, so probably a turn on output relay maybe needed for the LM3886.

Just make sure you are getting real IC's.  Had some Ebay LM3875's that were giving startup transients where the ones from Digikey were fine.  And I built at least 12 channels worth and those were the only two IC's that did have transients.

Sounds like a fun project to me either way.

[maty]

Deleted by maty.

[Folsom]

Tom’s 3886 boards would be fairly ideal. You need a hatsink exposed on the back, for sure.

[maty]

Deleted by maty.