diyAudio - Blog Entries
Go Back   Home > Forums > Blogs

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Old

Musical monitor: Some comments on the positive input in the original thread

Posted 7th July 2012 at 05:45 AM by fas42
Updated 16th July 2012 at 01:21 AM by fas42

By tnargs:

Quote:
I was assuming we were going to take something like a Behringer 2031A (2 way, 8", active, affordable) and see what tweaks are on the table.
Most perceptive ...

Quote:
Whenever I see a measured FR of a Behringer it looks nice and smooth and flat, off axis too, so it seems a decent start.
Exactly so.

Quote:
Although Lynno's post is true enough, I thought we would be keeping the drivers and looking at any gains from astute use of felt or resin (on or around the cone/dome), replacement of dust cap, stiffening or dampening the pressed steel driver frame... what else?
Possibly will improve the frame in some such fashion; and look at stronger coupling of the whole driver assembly to the carcase such that vibration is transferred in the most direct path to the surface the monitor is sitting on.

But these things will be only addressed after the electronics are sorted out, and I see how well the driver behaves itself at maximum SPLs.
...
fas42's Avatar
diyAudio Member
Views 658 Comments 0 fas42 is offline
Old

B-board Boxer Project : A Low Voltage Headphone Amplifier for 16 ohm Loads

Posted 7th July 2012 at 01:19 AM by rjm
Updated 29th September 2012 at 03:58 AM by rjm

I always seem to end up optimizing my headphone amplifier circuits for higher impedance headphones, this mostly happens because I own a pair of 300 ohm HD-600s and it is tedious to design for both the voltage requirements of high impedance headphones and the current requirements of low impedance headphones.

Not impossible, just, for the class-A designs I seem to be building recently, increasingly large, heavy, and impractical.

Complimentary transistor circuits, however, offer the opportunity to swap voltage for current at something close to the same design cost. They are therefore a practical topology for efficient class-A power delivery into low impedance headphones. As a design experiment, my aim is to discover how far I can leverage an ultra-low-voltage, unity gain circuit for compactness without sacrificing sound quality.

Ok. Back-of-the-envelope calculations:

A typical 16 ohm in-ear-headphone has a sensitivity of 100-105...
Attached Thumbnails
Click image for larger version

Name:	B-board Boxer AA.png
Views:	2184
Size:	26.6 KB
ID:	730   Click image for larger version

Name:	B-board Boxer AA LTSPICE.png
Views:	1436
Size:	124.7 KB
ID:	732   Click image for larger version

Name:	B-board Boxer AA 0.5 sch.png
Views:	817
Size:	19.6 KB
ID:	735   Click image for larger version

Name:	B-board Boxer AA 0.5 brd.png
Views:	655
Size:	21.7 KB
ID:	736   Click image for larger version

Name:	DSC_0083 800.jpg
Views:	263
Size:	134.3 KB
ID:	747  

Click image for larger version

Name:	DSC_0086 800.jpg
Views:	378
Size:	185.2 KB
ID:	748   Click image for larger version

Name:	DSC_0075 800.jpg
Views:	220
Size:	155.1 KB
ID:	749   Click image for larger version

Name:	DSC_0079 800.jpg
Views:	360
Size:	206.1 KB
ID:	750   Click image for larger version

Name:	DSC_0114 800.jpg
Views:	314
Size:	207.7 KB
ID:	751   Click image for larger version

Name:	DSC_0106 800.jpg
Views:	582
Size:	196.0 KB
ID:	752  

rjm's Avatar
rjm
diyAudio Member
Views 2433 Comments 7 rjm is offline
Old

Ceasar II 300B SE mono block upgrade Part #1

Posted 5th July 2012 at 07:36 PM by dvb projekt
Updated 24th July 2012 at 06:33 PM by dvb projekt (Titel changed)

A short quick upgrade for my Ceasar II Mono´s
to push the sq to the limit...


The last upgrade i made is to swap from the very good sounding Emission Labs 300B-XLS to

Click the image to open in full size.

the Sophia Electric Royal Princess 300B

Click the image to open in full size.

For me the best sounding 300B on the market!

The parts for further upgrading are:

Click the image to open in full size.

1st - The caps C2 & C3
2nd - The grid stoppers R5, R8 & R10


1st Upgrade




Click the image to open in full size.

The Mundorf silver/gold/oil are changed to the new Duelund Cast PIO-Cu.

Click the image to open in full size.Click the image to open in full size.
...
dvb projekt's Avatar
diyAudio Member
Views 1970 Comments 0 dvb projekt is offline
Old

My wiring scheme for the O2 in a B3-080 Desktop case with RCA's and 1/4 inch jack

Posted 5th July 2012 at 05:23 AM by MrSlim
Updated 5th July 2012 at 05:26 AM by MrSlim (fixed typo)

When I was planning the wiring scheme for the Baby Desktop O2, originally, I thought I would use 3 and 4 pin board mounted posts with equivalent pin connectors so all the flying wires could be disconnected from the board. I realized that would be too much work(and probably even more prone to disconnection so I only made one of the connections removable (the 3 pin P1 jack for the RCA inputs, beside the input J2 connector).
(note to add part #s for the pins and connectors I used)

Make sure you grind off the anodized coating around the holes on the inside of the panel before you mount the RCAs to get a good ground connection.

I used individual pairs of wire from solid core Cat5 cable for all the connections, and in my wiring description, I'll be using the wire colours from the cable I used. (it helped since I built 16 of them.. )

For P1 (for RCA input) I used Brown/white for Right and Blue/white for Left. The square pad(close to the the...
diyAudio Member
Posted in Uncategorized
Views 1927 Comments 2 MrSlim is offline
Old

ADAU1442 DSP - micro production line!

Posted 4th July 2012 at 03:36 AM by googlyone

I got to the point with my new audio DSP / crossover that I had no more excuse not to load the remaining PCB's I had manufactured.

I initially only loaded one of them, on the basis that if I had a clanger in the layout I could get a new spin of the boards.

Well the thing is all working and I have updated the DAC board - so the remaining five boards needed loading. I find a bit of PCB manufacture and loading to be quite therapuetic - as my previous blog entries will show.

This weekend I found my limit - loading the SMD's for these five boards - by hand in my toaster oven - took about three hours, then loading all the through hole parts, particularly headers and power supply parts blew away I would guess six more hours. I am over it!!!!

They do look pretty though!

Click image for larger version

Name:	IMG_0233_small.jpg
Views:	1511
Size:	763.0 KB
ID:	728

The only part remainig to be loaded on these boards is the ADAU1442 regulstor transistor. Thay will allow me to...
diyAudio Member
Posted in Uncategorized
Views 5654 Comments 1 googlyone is offline
Old

Musical monitor: And the story continues ...

Posted 4th July 2012 at 03:22 AM by fas42
Updated 16th July 2012 at 01:22 AM by fas42

The project will proceed, exactly as stated in the earlier posts. Just a shame people couldn't help injecting unhelpful comments, and I was provoked into responding. Ahhh, well ...

So, now some peace and quiet! Hopefully at least a few will find something of benefit in what I relate here, and my methods may resonate with some.

Anyway, may all enjoy good listening, no matter what!

Cheers,
Frank

Postscript: Hah! Dumb me, I didn't spot this earlier: http://www.diyaudio.com/forums/blogs...scientist.html. Some excellent thoughts and comments ...
fas42's Avatar
diyAudio Member
Views 444 Comments 0 fas42 is offline
Old

loading surface mount IC's

Posted 1st July 2012 at 01:21 PM by googlyone

One thing that always used to give me grief at home was loading fine pitch surface mount IC's.

I recently bought a toaster oven having read several people's experience using these to relow SMD's.

I lashed out and bought the el-expensivo fan forced model, as this was in one forum reported to give more even heat. After some playing around I concluded the oven would actually be really very good.

I found that if I did the following (with my oven):
- Turn on and run on 2 bars until temperature = 100C,
- Turn down to one bar, and run for 60 seconds,
- Turn on two bars and continue until the temperature is 210C,
- Turn all bars off, leave fan on and open the door a crack.

The heat continues to increase to about 220, and the profile is really very close to many manufacturers recommended profiles.

Click image for larger version

Name:	temp_Profile.jpg
Views:	303
Size:	127.9 KB
ID:	726

I don't use silksceeens, I use a syringe and put a very little...
Attached Thumbnails
Click image for larger version

Name:	DSC03829_small.jpg
Views:	583
Size:	723.6 KB
ID:	725  
diyAudio Member
Posted in Uncategorized
Views 2111 Comments 0 googlyone is offline
Old

OPTIMUS STA-2160

Posted 29th June 2012 at 08:27 PM by Antoinel

Hello
Does anyone have the schematic of the power amp section of the subject AM/FM receiver? Please share it. Thank you
diyAudio Member
Posted in Uncategorized
Views 932 Comments 1 Antoinel is offline
Old

Mathematics of DAC droop correction

Posted 29th June 2012 at 06:09 AM by abraxalito

Here's one of the clearest articles I've seen which explains the background and a couple of solutions to DAC roll-off.

Flatten DAC frequency response | EDN

Both the solutions proposed compromise the dynamic range. My own solution, a hybrid analog/digital approach relies on DACs being cheap - I've termed it 'LAID' which stands for 'Longitudinal Array of Inexpensive DACs'.
abraxalito's Avatar
diyAudio Member
Views 848 Comments 0 abraxalito is offline
Old

Front Panel Express Panels for the O2 Headphone Amp

Posted 28th June 2012 at 05:49 PM by MrSlim

The B2 file is for the BOX Enclosures B2-080 case, that is used in the standard "transportable" O2

The B3 files are for front and rear panels on a BOX Enclosures B3-080 case, used in the "Baby" desktop configuration of the O2. This configuration includes mounting holes for a 1/4" headphone jack and volume control on the front, with all the rest of the jacks and buttons on the back, along with a pair of RCA jacks for input. The PC board in Baby Desktop is installed backwards.
Attached Files
File Type: zip B2.zip (945 Bytes, 139 views)
File Type: zip B3_front.zip (565 Bytes, 139 views)
File Type: zip B3_rear.zip (823 Bytes, 123 views)
diyAudio Member
Posted in Uncategorized
Views 813 Comments 0 MrSlim is offline
Hide this!Advertise here!

New To Site? Need Help?

All times are GMT. The time now is 08:31 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2015 DragonByte Technologies Ltd.
Copyright ©1999-2015 diyAudio

Content Relevant URLs by vBSEO 3.3.2