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Dynaudio PPM2 Loudspeakers

Posted 11th February 2011 at 05:36 AM by simpsonjp

I just bought a set of Dynaudio PPM2 monitors on auction at Audiogon. Does anyone know where to get any data on these speakers (ie spec sheet or reviews). Anyone own a set or have heard them?

Thanks,

Jeff
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PC Crossovers

Posted 10th February 2011 at 08:36 PM by DougL

This looked Interesting.

http://www.diyaudio.com/forums/multi...ml#post1033586

I'll have to research that.
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Digitally controlled class D

Posted 8th February 2011 at 08:24 PM by alexcp (My DIY projects)
Updated 17th December 2011 at 02:24 PM by alexcp

I wanted to build a Class D amp based on TI's PurePath chips - e.g. TAS5086 PWM processor and a few TAS5162 power stages - until I read Bruno Putzeys' "The Truth About Digital (Class D) Amplifiers". He makes a convincing argument that digitally controlled class D is a dead end street. I also noticed that very few people around here have been writing about PurePath. Shall I look at the UcD patent and application note, as well as ready made Hypex modules, instead?
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Wide-band RF filtering for mains

Posted 5th February 2011 at 05:07 AM by abraxalito
Updated 2nd March 2011 at 12:10 PM by abraxalito

Since Ostripper asked about mains filtration on the RF & Audio thread, here are some notes and ideas. I haven't built any of this yet - if you decide to, I'll be interested in any results - photos and listening reports. Be careful with this stuff, its at mains potential.

Pre-built mains filters are of some use in audio, but they're not really optimised for high-end sound. For audio source components, the draw is normally under 100W and so the current (assuming here 230V supply) is under half an amp. Few if any off the shelf mains filters are designed for such low currents.

Second, the commercial filters assume that we wish to stop conducted interference getting out as much as prevent muck getting in. The internal noise would normally only come from the rectifiers in a linear power supply (SMPSUs are a totally different matter). Once we've snubbed them (you have done that already right, or are using soft-recovery or schottky diodes?), with a linear...
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service manual NAD 7225 pe

Posted 1st February 2011 at 10:01 PM by migouel

Hi all. I have a NAD 7225 PE Amp that seems to not power up. Does anyone have a service manual for it or schematic? Where can I find info to help me fix the tuner? 4 Fuses Blown,Display,FM scan works ok.

Thanks
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My "Salas hotrodded DCB1" build

Posted 27th January 2011 at 08:06 AM by Rodeodave

I built the 10R version for now, maybe I'll up the current later. The power resistors I used are non-inductive planar 10R 5w thick film resistors (BI Technologies BPC5100J). The noise figures are comparable with metal film it seems. I just thought I'd give these a try, and since I'm using many fancy flavoured parts (at least for my taste) it fits the bill. I had to remove the original legs, which were some clamp-on soldered types, and fit them with bent copper leads since the original spacing was too small for the board. If you look close enough you can see it in the second picture.

Click the image to open in full size.


The MOSFETs are IRFP140N/9140N. The 5-LED chain is matched to 9.30V/9.29V (values measured in circuit), using 12VDC and 1k in series with it. The 3-LED chain was matched to 5.59V/5.58V (measured in circuit). The 5-LED chains are fed by 2SK170 that I once measured to...
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MR211's Blog

Posted 25th January 2011 at 07:23 AM by asterkao
Updated 3rd September 2013 at 02:22 AM by asterkao

http://kao211.blogspot.tw/
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Old

Compact PCB For All JFET Circlotron

Posted 25th January 2011 at 12:59 AM by Michael Rothacher (Audiohobby.com)
Updated 2nd October 2011 at 12:59 PM by Michael Rothacher

This is the artwork for the PCB in the pictures. It fits into the ExpressPCB miniboard profile so it's a little cheaper to have made.

It will be necessary to check the orientation of the bias pots (I can't remember). I wouldn't want you to blow-up your $30 JFETs.
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All JFET Circlotron

Posted 22nd January 2011 at 11:29 PM by Michael Rothacher (Audiohobby.com)

I've been mostly out of the audio hobby for a while, but I've had a few inquiries about the SemiSouth version of the Amazing FET Circlotron as of late. So, I wanted to post the performance graphs here before I lose them.
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Old

Getting started again is harder than I imagined!

Posted 8th January 2011 at 01:09 PM by wintermute (Wintermutes Rantings)
Updated 18th January 2011 at 11:45 AM by wintermute (audigy now working reliably!)

It seems I have been doomed to not do any of my DIY projects since my main computers hard drive crashed followed shortly after by my laptops (the laptop has had another crash after that, and the drive is now on the way out again!!)

After having to pull the cables out of my chipamp last week and plug the TV into it (because the MythTV box refused to play a DVD and I can't plug the DV18 DVD player direct to the chipamp because it has no volume control) I decided I had better get off my backside and finish my pre/active crossover. I had to do it again tonight as well (plug the tv into the chipamp), sigh...

This is all because my playmaster had something in the pre die again and is only working on one channel and I just haven't been bothered fixing it. I thought that being inconvenienced might make me more likely to finish the other projects but it has been broken for about 6 months

So on Monday I decided that I should re-install Holm-Impulse...
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