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Old 28th August 2005, 05:59 AM   #651
needlz is offline needlz  United States
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Just found a killer heatsink source.

Contact Rus directly (barrredboss@yahoo.com) and he will cut it to any size you want. I had him cut the 12" piece in half then in half widthwise for 4 pieces to fit the Ref amp perfectly. Ultra cheap pricing.

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Old 28th August 2005, 06:20 AM   #652
maf_au is offline maf_au  Australia
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Ok, it's running, sounding sweet!

I've been listening for a while at reasonable levels, and the back panel is warm, not hot to touch. Those resistors inside are pretty hot though

Initial impression is that it's slightly drier than the other amp, but not unpleasantly so. I'll let it burn in for a few days before I get critical... It sounds very good to my ears.

It's pretty quiet with no source until the volume gets to about 75%, then there's a bit of hiss. This is with Russ's Freebird in standard configuration, things are quite loud enough at 25-33% on the dial.

I'm getting a bit of hum directly from the tranny (not through the speakers though)

Michael

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Old 28th August 2005, 06:22 AM   #653
maf_au is offline maf_au  Australia
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Old 28th August 2005, 12:08 PM   #654
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Quote:
Originally posted by maf_au
Ok, it's running, sounding sweet!

I've been listening for a while at reasonable levels, and the back panel is warm, not hot to touch. Those resistors inside are pretty hot though

Initial impression is that it's slightly drier than the other amp, but not unpleasantly so. I'll let it burn in for a few days before I get critical... It sounds very good to my ears.

It's pretty quiet with no source until the volume gets to about 75%, then there's a bit of hiss. This is with Russ's Freebird in standard configuration, things are quite loud enough at 25-33% on the dial.

I'm getting a bit of hum directly from the tranny (not through the speakers though)

Michael

Pic of the front panels:
Hi michael,


If the hiss you are hearing increases when you increase the volume then the hiss is most likely coming from your source(CDP prolly) one way to know for sure is to check for hiss with the inputs to the preamp shorted and the volume up.

If you had hiss with nothing connected to the preamp inputs the preamp is likely picking up a little RF/EMI noise. which could be coming from many sources. You could change the RF rejection cap on the FreeBird for a higher value and see if that helps(200pf or 330pf should help) I would not go over 330pf and start at 200pf.

Just for reference sake when I say the input shorted I mean the input and the input ground connected. One easy way to do this is to take an old RCA cable with male ends and cut it so you have 2-3" of cable on the jacks. Then solder the conductors together and you now have a pair a shorting pigtails.

Your offset is just fine, well within limits,

You will notice right away an amp like this is much more revealing than most, which can come off harsh at first if you are used to something more veiled , but it will grow on you. Great work!

Cheers!
Russ
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Old 28th August 2005, 08:19 PM   #655
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Quote:
Originally posted by Russ White



You will notice right away an amp like this is much more revealing than most, which can come off harsh at first if you are used to something more veiled , but it will grow on you. Great work!

Russ you got me thinking here. what equipment are you using?

As a test i did some experiments today. i decided to remove all my "esoteric" stuff. that being DAC - Ribbons. so i was left with Rotel 951 frontend (modified) and singel morel 5" with morel tweeters. (representing the average owned top-end speaker) and a passive preamp. that alone being reasonable hifi equipment,

I then hooked the amp upto the system with my configuration (that being described in a previous post) well the outcome were not as detailed as what i am used to (veiled if you want to describe it as such). then i changed the amp back the original configuration. that was a improvement put still not the detail of my reference system. the soundstage is 2 dimentional and the tops were not as smooth as my ribbons i and were missing hi freq detail. (that is were a super tweeter helps) the high freq were "harsh" compared to my ribbons and class A amps. (but that is just a general impression i have of dome tweeters. you get converted very quickly when you use ribbons, it is just way smoother) it is not the amps fault

so the i think we have to be very carefull as to how we test and compare the sound. if you do not have a dedicated DAC doing duty in your system you are robbing yourself from 40% of the detail, (not all DAC's are good so be carefull even in that department) the average Rotel is veiled compared to say a Marantz which is more forward in the mids, and not all the rotels are the same. some being much better than others and the same with the marantz

this little amp is one of the best designs that i have had in my system and comes highly recommended. I have had better but they cost 300 times the price of this amp. I just think we have to be objective when we give our views and state what equipment is being used when we give our opinions. unfortuneately the average person does not have access to equipment that resolves the sound as it should and it then becomes a case of what might work best in your system. (this amp fitting the bill, and doing a good job of it)

I know my system compare easily with systems in the $ 18 000 (and above) region but not every body listens to that kind of equipment so it becomes difficult to do a comparison and not all the changes or configurations work for everybody.

so guys when you have completed your amp and do a evaluation please state your equipment used. this little amp deserves it

cheers
Rudi
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Old 28th August 2005, 09:27 PM   #656
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Quote:
Originally posted by rudi
...it is not the amps fault.
You will only know if you change only the amp.
To test a component you should do it on the system that you know best, the one you listen to everyday, for a long time.
You know it better, and you know how it sounds.
For me, this means my main system. I have other systems, but this is the one I use for a serious test.
Change the amp, and it shows.
Change the preamp, and it shows. The source, etc.
But ony one thing must be tested, if you want to be sure.
For better or for worse.
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Old 28th August 2005, 09:47 PM   #657
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Quote:
Just found a killer heatsink source.
This was the source for the heatsinks in the group buy kits. I highly recommend them. I will probably be offering 3 or 4" pieces again to go with the RevC kits.
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Old 29th August 2005, 02:54 AM   #658
needlz is offline needlz  United States
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I am stuffing the amp into a mighty small encloure so I had him cut out the middle fin so it will fit. $20 will get you enough heatsink for 4 amps.
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Old 29th August 2005, 06:51 AM   #659
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Quote:
Originally posted by carlosfm


You will only know if you change only the amp.
To test a component you should do it on the system that you know best, the one you listen to everyday, for a long time.
You know it better, and you know how it sounds.
For me, this means my main system. I have other systems, but this is the one I use for a serious test.
Change the amp, and it shows.
Change the preamp, and it shows. The source, etc.
But ony one thing must be tested, if you want to be sure.
For better or for worse.

Hi Carlos

you are obviously not getting what i am saying here.

I have already tested the amp and it good. i had to change some values so it does not sound like your ordinary modern day commercial amp and in order to sound a bit sweeter in the mids and less stressed. in my refference system it sounds great but i wanted to know what it sounded like in less expensive and less revealing systems. that is why i took it down to the average system level.

I wanted to know what other people were experiencing when listening to it without the resolution of a DAC and ribbons.

this little amp already prooved itself of being 100X better than the ordinary chipamp inverted or non inverted , and that is the only reason why i would persue the development of this amp, because it sounds like a BIG SS amp not like a good sounding chip

i hope i made myself clear this time.

cheers
Rudi
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Old 29th August 2005, 01:17 PM   #660
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Default Sources

Hi All,

I had not previously mentioned my sources because I have tested with quite a few.

I currently have the following immediately available(some other stuff packed up).

1)A Cambridge Audio DAC3.
2)A Denon DVD-2910 (professionally modded with opa627 for outputs).
3)A Denon DVD-3910(modded as the 2910).
4)A newly aquired DVD-5910.
5) For initial bench testing and PC listening I have a USB DAC of my own creation.
6) I also have a Creative Audigy 4 for PC use.

I have listened to my REFs with all of the above.

My favorite source is the DVD-5910 Simply because my collection of SACDs is quickly growing, and that little beauty rocks.

For preamp(in my stereo listening room) I also use my own freebird, as well as some unpublished designs of my own.

I also use as a front end in my HT room where I do some testing a Denon AVR-3805 which has analog 7.1 preouts from any source which is especially nice since you can feed it a DSD signal direct from the 5910. I love it. The Denon products are some of the most widely modded pieces of gear out there, so they make good kit for those of us who like to tinker.

I used to own some tube gear, but I quickly sold it. I don't personally care for it. I like my gear to reveal everything, but not add music of its own. If I wanted to inject harmonics and color I would run my signal through a DSP. Just kidding of course. No offense to the tube dudes.

Cheers!
Russ
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