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Other options for a headphone amplifier.

Posted 15th December 2011 at 01:02 PM by rjm (RJM Audio Blog)
Updated 15th December 2011 at 01:08 PM by rjm

While I wait for the guys at 47 labs to get the Treasure 0247 together, I took a look around at some of the alternatives.

The Yulong D100 looks quite attractive and for about 2/3 the price of the 0247 kit you get a fully assembled unit!

review at head-fi

Or if you can do without a DAC, HLLY audio has your standard "transistor buffered op amp" implementation in a no-frills case:

HLLY RMK-5

It's listed at $240 but for sale on eBay for only $99 right now.

Of course there are dozens, but I single those two out as being particularly deserving of "honorable mentions". I'm still set on the 0247 though.
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Old

47 Labs "Treasure" Model 0247 DAC/Headphone/Preamplifier

Posted 14th December 2011 at 05:56 AM by rjm (RJM Audio Blog)
Updated 17th December 2011 at 01:36 AM by rjm

Just placed my order for this. I am customer no. 00028!

47 Labs web page

I figure I owed it to them. 47 Labs has been good to me, and the DIY community over the years, one way or another: gainclone, phonoclone, even the DAC-of-the-Klones.

Besides, several reasons:

1. I really want to finally hear 47 labs gear, instead of trying to reverse engineer it all the time!
2. It will be interesting to compare it against the sapphire amp.
3. I'm sure it will be fun to build and examine up close.
4. It's my Christmas present.
5. And hammertone. Finish a audio product in grey, or even better, green hammertone, and its as bees to honey...

Will blog the unboxing, building, and testing right here.
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Old

Zen V4, updated

Posted 13th December 2011 at 07:20 AM by alexcp (My DIY projects)
Updated 17th December 2011 at 01:41 PM by alexcp

In 2009, Penultimate Zen aka Zen V4 was my first solid state build. I used the parts that were available, did not know much about making it work well, and did not have test instruments beyond a cheap multimeter. Also, I did not have a preamplifier to work with it or speakers sensitive enough to enjoy its 25W. As a result, the amplifier turned out not quite satisfactory and for two years has been gathering dust and my wife's complaints. I was thinking about scrapping it and reusing the enclosure for something more useful. Instead, I reworked it.

I removed one of the two power transformers (moving from dual mono to stereo configuration), replaced my original dodgy Chinese PSU filter caps with Mundorf M-Lytic HC, replaced internal low voltage wiring with thick speaker wire, reconfigured grounding (so it is finally safe!) and installed balanced inputs with input transformers. What a change in sound! With my Exposure CD player, B1 clone preamp and Heresy III speakers, the amp...
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Old

RJM Audio Kits : Available ... again!

Posted 11th December 2011 at 11:09 PM by rjm (RJM Audio Blog)
Updated 13th December 2011 at 05:08 AM by rjm (updated with price info)

Back by popular demand, I have decided to go ahead and prepare full kit version of the VSPS300, Phonoclone 3, and Sapphire projects.

10 kits of each project will be available - contact me to reserve.

Phonoclone Kit : $125 (10 availble) Set of two boards and components to populate.
VSPS 300 Kit : $117 (10 available) Set of two boards and components to populate.
Sapphire Kit : $113 (10 available) Set of two boards and components to populate.

Kits will be shipping shortly after the New Year.

Current status: necessary parts shipped from Mouser, should be able to assemble kits this weekend. Also have to prepare the documentation.

RJM Audio Kits
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Old

Don't ground your pot

Posted 10th December 2011 at 12:28 AM by jtktam (Newbie audio DIYer)

I always ground my pot to the star ground on my other projects.. seems that for some reason this shuts down the left channel on my sapphire..

went through the whole diagnostic to narrow it down to the pot.. (or so i thought) and replaced it with a new one.. i got it working.. then i grounded it and it didn't work again..

on a hunch i removed the ground wire.. and VIOLA.. sweet sound from both cans!

-joe
diyAudio Member
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Old

But how does it sound?

Posted 9th December 2011 at 12:42 PM by jtktam (Newbie audio DIYer)

Hard wired the left output to the right side (running mono R on both headphones)

testing the sound of the amp.. it's truly amazing.. nothing i have compares to it..

need to get it to the store to put it on demo.. no time to work on fixing this one.. worked til 2am last night and woke up at 4:30am.. too tired

i will probably end up building another set of boards and swap it out and debug later..

-joe
diyAudio Member
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Old

bumpy ride

Posted 9th December 2011 at 12:40 PM by jtktam (Newbie audio DIYer)

The sapphire amp is done. I ended up building an external power supply, not enough room in the hammond to put everything.

I had overheated Q3 on one of the boards and the DC output was at 8vdc! luckily I always check offset before I plug headphones in.

Ended up replacing it and it works fine..

I had originally wired the chassis for dual mono output into a Y harness back to stereo.. then my friend suggested that i wire it directly for stereo.. no sense in spending time on the harness..

upon rewiring, the left channel refuse to work.. i didn't even touch it..

i must be jinxed

-joe
diyAudio Member
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Old

My systems

Posted 4th December 2011 at 11:41 AM by alexcp (My DIY projects)
Updated 12th May 2013 at 07:41 PM by alexcp

Someone pointed out that it's interesting to see all the components in a system, rather than discuss them individually. I liked the idea - I think it also shows what projects ended up actually useful - so here are my systems (I have four with diy components).

The music I listen to is an eclectic mix of classical music (such as Rachmaninov and Tchaikovsky), opera (mostly arias), jazz (Armstrong) and some pop music.

The first system is the one I listen to the most:
  • exposure 2010S CD player with Tentlabs low-jitter clock
  • B1 clone preamp
  • F5 clone
  • Vintage Celestion DITTON 15XR speakers

The second system is the testbed for whatever project I may be working on:
  • Audio Analogue Crescendo CD player
  • B1 clone preamp
  • Zen V4 with SiC power JFET in the gain stage
  • Klipsch Heresy III speakers

The third is the best sounding so far, has the highest WAF and is likely to stay around for some time:...
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Old

RJM Sapphire

Posted 4th December 2011 at 01:58 AM by jtktam (Newbie audio DIYer)

Another weekend, another project.

Started on the RJM sapphire headphone amp this weekend. Having a bit of trouble with the transformer I ordered. According to the BOM they specified a Triad 25VA unit.

I got them from Mouser and it was huge, the wires were unwieldly and I didn't think I would use them

Looking at the pics posted by RJM, they used Amveco, which is my normal brand.. DOH!

So off to digikey to order yet another set of transformers..

Also need to figure out if I would use the bridge rectifiers I already bought, or use Peter Daniels rectifier PCBs and use the MUR280 instead.. the latter will be faster and cost more.. the former might not perform but it's cheap

-joe
diyAudio Member
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Old

Interesting blog post about fake chips

Posted 3rd December 2011 at 03:27 AM by abraxalito
Updated 5th March 2012 at 02:50 AM by abraxalito

On Counterfeit Chips in US Military Hardware bunnie's blog
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