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Squeezebox SB3

Posted 10th October 2010 at 12:00 AM by audi0

After much deliberation I've decided to 'jump in' and modify my Squeezebox SB3.
I have read many threads on this and other sites gaining lots of ideas of what I want to try to achieve, basically as follows:

improved power supply, dump the wall wart and build a linear supply 5V @~ 3amps
improve the analogue section, initially trying different op amps and upgrading capacitors
remove the inductors from the digital out, add 75 coax and BNC connector (maybe add a transformer?)
upgrade to the 3.3V supply to the clock
build a new enclosure similar to a Peter Daniel amp, chunky aluminium back and front with timber sides (copying is the greatest form of flattery!)

I have made a start, opened it up and discarded the old plastic box. De-soldered the connection board and set aside, then soldered temporary wires for power L & R out and ground back to the connection board (temporary connection)

To get the board into...
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Old

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

Blog Post the Second.

Posted 11th September 2010 at 07:29 PM by chris661

Well, here we are again, dear reader.

Today I received my Fostex FE126eN drivers from Dave, who has been very helpful in the whole process.

I have the cabinets (small, folded Voigt pipe, herehere. Partially made, as I needed the drivers in-hand to measure the cut-out required for the partition. Anyway, when I got the wood cut (asking specifically for 15mm MDF), they gave me a pile of 18mm MDF, with all the correct cuts. This would've made assembly a nightmare, so I phoned them, explained what had happened, and they sent someone over with the 15mm cuts. Sorted.

I decided to use the 18mm thick baffles as a baffle, give the drivers a run-in. Even after not very long, they sound bloomin' lovely. Sure, the treble's a little forward, and the bass needs significant eq (as you'd expect). But yeah, vocals are things are awesome to listen to. These are just far better than anything I've ever owned.

So, with the drivers bedding in nicely,...
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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

Further education...

Posted 8th September 2010 at 01:35 PM by chris661

Well, this is a first. A blog.

Second day of college (6th form, etc), and all seems to be going well. The teacher seem reasonable enough, even though they do seem to like going back to basics. I expect that will change when the course is properly underway.

I'm taking AS level (A-level comes next year) Physics, Mathematics, Biology and Chemistry, with the intent to go into either a medical career, or to become an engineer of some kind (maybe work for B&W, Celestion or KEF........). Anyway.

What was I up to? Oh yes, changes that will undoubtedly take place. I really, sincerely hope that the teachers will stop telling everyone how much of a step up AS level is from GCSE, and actually do some teaching!! We were warned at the open evenings, in the introductory speech by the principal, by our secondary school teachers, even our parents, friends etc that have been through the experience.

Right. That's got that out of the way. Now...
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