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Old Majestic Car Amp

Posted 2nd September 2011 at 01:00 AM by DigitalJunkie

I got this amp in 'fried' condition from a friend many years ago. I finally managed to get it working,and I've been using it for my subwoofer amp ever since,probably about 10 years now? It's not the greatest amp,but it has served me very well on sub duty.

It claims to be 200W per channel, and bridgeable to 400W. It might even pull that off,on a good day.

Anyways,I had some very poor scans of the schematic for this amp(which I later discovered was almost identical to a 4 channel Rockwood amp.) I managed to re-draw the basics,and thought I'd post it up for the forum to check out.

I've been thinking of taking this amp to the bench to do some tests,and maybe some tweaks. I'm all ears if anyone has any thoughts?

Here's a link to the redrawn schematics,I might put the original scans in there also.
Some component values are missing,I was going from memory,and what I could make out from the original scans.

MA-9400 pictures by Nothing40 - Photobucket
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EMT 950 Turntable

Posted 31st August 2011 at 04:00 AM by Davo58

Has anybody had to try and play discs that run at slower speeds than 33 rpm.
We have some 24 rpm and 16 rpm discs that we need to digitise and was wondering if you hve been able to slow down your EMT950 to be able to do this.
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Please help to decide box for FE103En

Posted 29th August 2011 at 08:54 PM by audiomovil

i want to build a box for my new FE103En, please help to decide between Buschhorn Mark II or the Sperrin and Vampyr-v, from Woden Design.
I use a Yamaha amplified 10" sub and Yamaha amp 60x2, for use in a living room 11 ft by 13 ft, for movies and music., jazz and rock.
Thanks for the help.
Gustavo Espino from Jalisco México.
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Best source for TX2575 Naked Z-Foil Resistor

Posted 28th August 2011 at 07:52 AM by dvb projekt
Updated 28th July 2014 at 10:12 AM by dvb projekt

All members who want to use the "holy grail" audio resistor,

the TX2575 Naked Z-Foil,

could order it direct at Texas Components.

That´s the cheapest way to get it IMO.

They have also great Trimpots with Bulk Metal Foil Technologie.

P.S.: If you send a mail to Arbie, send her regards from me!
Attached Files
File Type: pdf 5 Reasons to Specify Bulk Metal Foil Pots.pdf (800.9 KB, 1111 views)
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Conn strobotuner

Posted 27th August 2011 at 01:17 AM by blackveilbridessixx

does anyone know how much a conn strobotuner model st 11 is worth?
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Projection lens and Fresnel lens

Posted 23rd August 2011 at 11:37 AM by djhot143

Hi to all friends,I am new here.
My name is DHIRAJ from mumbai,india.

I need your help, I want to make a projector but i am not getting parts of it.
Can anyone tell me where i can buy projection lens and Fresnel lens in Mumbai. plz help me.
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Rating: 2 votes, 4.00 average.

TDA1541A DAC Module V3.0 - Out of production

Posted 20th August 2011 at 08:32 AM by dvb projekt
Updated 19th June 2013 at 10:27 AM by dvb projekt

The Red Baron

aka TDA1541A DAC V3.0

Click the image to open in full size.

The evolution brings the following changes

- Direct shunt voltage inputs with shortest onboard traces
- I2S In-/Outputs with shortest onboard traces
- Upgrades DEM Synchronizer
- Onboard Grounded-Gate MOSFET Current Buffer I/V Stage
(-ecdesigns- MK7 version)
- Compacter design

Still on the module

- Separate GND-Trace for DEM-Synchroinizer
- Master/Slave connectors for parallel DAC module usage
and external I/V Buffer stages e.g.
Tube-I-zator & DDNF Stage
- Groundplane
- no SMD Design

Click the image to open in full size.

The PCB has the following data:

Material: FR4 - 2mm
Layers: 2
Board size: 125x73 mm
Attached Files
File Type: zip TDA1541A Project - BOM - for The Red (9.0 KB, 989 views)
File Type: pdf The Red Baron DAC.pdf (28.9 KB, 2011 views)
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Posted 17th August 2011 at 11:10 PM by Erik F

I am back
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LM3886 x 3 First Test

Posted 16th August 2011 at 05:29 AM by panson_hk

I briefly measured the LM3886 x 3 parallel board this morning. THD vs freq for one, two in parallel and three in parallel are measured.

Load of 4 Ohm was also tested. When using one 3886, the on-chip protection activates periodically when doing low frequency (~ < 500 Hz) test. No such protection operation happens for the same output level for higher frequencies (>1kHz). The problem goes away when using 3886s in parallel.

More systematic tests will follow.
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LM3886 x 3 continue

Posted 15th August 2011 at 05:14 AM by panson_hk
Updated 15th August 2011 at 05:58 AM by panson_hk

The DC offset of the three 3886 are interrelated. Hence, adjusting them all 0.0 mV is tough if not impossible. I now made them all 8.9 mV to achieve DC balance. Next will adjust the AC gain. DC offset may need readjust again. This is a game for $ (cost foe DC servo) vs time.

The three 3886 have identical batch number.
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