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Burning Amp 1

Posted 9th October 2010 at 06:52 AM by alexcp (My DIY projects)
Updated 16th March 2013 at 02:40 PM by alexcp

To get warm and comfortable on long winter evenings, I built myself a Burning Amplifier 1. With its 300W quiescent dissipation and ineffable ((c) Nelson Pass) sound, it is a nice winter time companion.

I used four heatsinks, each holdings two IRF250 MOSFETs in TO-3 packages and a PCB. Each pair of heatsinks is cooled by a quiet 140mm fan. Power supply uses a 400W toroidal transformer and 2x40,000 uF per channel; it is a dual mono configuration. The amplifier is housed in a 5U 400mm deep enclosure from modushop. Their "pierced base" was very handy to keep all the parts together without sacrificing the looks. Total weight is 23 kg (about 50 pounds).

The knob on the front panel was designed as volume control, but it looks ugly, so I will remove it.
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my projects

Posted 7th October 2010 at 01:17 AM by Bigun

I've added comments to this blog to fix the broken links and add additional links to new projects
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Lynn Olson's Book List

Posted 30th September 2010 at 02:52 PM by DougL

This speaks for itself:
http://www.diyaudio.com/forums/multi...ml#post2318365
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My new speaker system

Posted 25th September 2010 at 12:03 AM by Sammumba

My job at the garage has been reduced to 4 days a week, which is great as it means I have an nice long weekend break. With all the free time I'm going to be working on my custom car stereo system.

My Nissan Micra probabaly doesn't have the best speaker system around.. Which is just as well because I'm going to upgrade it!!

I'm going to break open my old PC speaker sytsem

Click the image to open in full size.

And install it in my car. The sound qouality is amazing and I'm sure I'm going to get a lot of enjoyment out of it too.
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Old

Zen IV

Posted 13th September 2010 at 05:05 PM by DougL
Updated 15th September 2010 at 10:37 PM by DougL

Nelson has created a storm of interest with the Zen I/V.

I have a DAC that I can use this with, a K&K RAKK DAC Mk1.

Currently, it has a passive supply and a switchable shunt resistor.

So I am brainstorming on what it would take for an active Zen I/V with a shunt volume control, and both SE and Balanced outputs.

Basics: PCM1794 has differential outputs with 8 ma current output.
http://focus.ti.com/lit/ds/symlink/pcm1794.pdf
So I need 2 Zen I/V per channel.
At present, I am running a DCX2496 Digital crossover, so balanced outputs are a plus.

I am considering using the buffer from this post.
Since bipolar supplies are required for the I/V section, a buffer that does not require additional caps seems prudent.

For the volume control, either http://www.kandkaudio.com/linestage.html Shunt Stepped attenuator or a single LDR replacing the K&K unit.

Finally,...
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Old

Need 150 to 200watts amplifier achematic

Posted 10th September 2010 at 12:44 PM by yoyomaster01

Hi to everyone!!!

I'm new i this site
I just want to ask for some pcb and schematic for a 200watts amplifier

Can P3A amplifier from ESP modified?
and add some more output tannies?
maybe 3 pairs?

I want to use MJE2955 and MJE3055 for the outputs.....

Any body?
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Old

Common emitter amplifier design II

Posted 9th September 2010 at 07:27 PM by wakibaki

In the earlier post, basic common emitter amplifier design, I made reference to increasing the gain of the amplifier by bypassing the emitter resistor R[SIZE="1"]E[/SIZE].

In this case the gain referred to is the AC gain, which is the signal gain, and which is the gain we are primarily interested in with regard to audio amplifiers. The gain previously calculated was the DC gain, which was numerically identical to the AC gain, but since the amplifier was decoupled from the preceding stage with a capacitor, there was no DC applied to the transistor other than that provided by the bias network, which set the standing current to 1mA and the output voltage to 10V. DC gain and offset is important, because a decoupling cap can be avoided in some cases, but not here.

In the earlier post the gain was stated to be R[SIZE="1"]C[/SIZE]/R[SIZE="1"]E[/SIZE]. This was a simplification, and, more strictly the gain is R[SIZE="1"]C[/SIZE]/(R[SIZE="1"]E[/SIZE]...
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Old

100-160w mosfet amp

Posted 7th September 2010 at 07:30 PM by johnalexwarren

This is my first serious amp project. It uses the IRFP9240 & IRFP240 MOSFETs and delivers 100WRMS into 8Ω or 160WRMS into 4Ω at 0.1% THD.

Many thanks go to Edwin Paij @ AED (http://users.swing.be/edwinpaij/welcome.htm) for the design .

I have now gathered the majority of components and am currently active in the forum looking into PSU design...
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Old

Turntable Technics SL-3 Wiring Diagram wanted

Posted 6th September 2010 at 03:45 PM by SirErik

Hey, I've got my Technics SL-3 turntable power supply damaged by a high voltage burst from the power station. I've found out that the transformator is damaged, but I haven't been able to find a new one. The number on it is SLT48DT 15E. I need to know either where to buy a new transformator or what specifications (voltage 240/? . .) this transformator has. Anyone who can help me solve this problem?
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Old

LME49830 based amp

Posted 4th September 2010 at 06:02 PM by alexcp (My DIY projects)
Updated 8th October 2012 at 10:26 AM by alexcp

This is an implementation of National's reference design for LME49830 with two matched pairs of 2SK1530+2SJ201 per channel. The PCBs were made using National's gerbers (thus National's logos). Sounds surpisingly good, but it has just been completed; I did not have a chance to listen to it carefully yet.

Update: I rebuilt the amp as a pair of monoblocks, each delivering healthy 200W into 8 ohms. It now looks tidier.

Update: the original Gerbers from National are nowhere to be found since national.com was merged into ti.com. Attached are the original archives downloaded from the national.com.
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