Chip Amp Photo Gallery - Page 252 - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 6th September 2013, 07:30 AM   #2511
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Quote:
Originally Posted by davym View Post
.............Readings when on are - Right in = -2.9mv Right out = 0.8mv
Left in = -2.9mv Right out = 0.8mv

However with old cheap test speakers connected but no input I get -
Right out = 2.9mv
Left out = 1.2mv

Probably the test speakers i'm thinking .................
The change in output offset is due to the change in input conditions.
A shorted input effectively inserts a Source Resistance of zero ohms into the input.
An open input inserts an effective infinite resistance into the input.
Your actual Source will have it's own output impedance. This becomes the Source Resistance seen by the amplifier.

You should check output offset with shorted input and with the Source/s connected and with the Source/s switched on and switched off.
__________________
regards Andrew T.

Last edited by AndrewT; 6th September 2013 at 07:50 AM.
  Reply With Quote
Old 6th September 2013, 08:04 AM   #2512
jemraid is offline jemraid  United Kingdom
diyAudio Member
 
Join Date: Aug 2004
Location: NE Derbyshire
Hello all,

Two free programs for editing/resizing pics; one is Irfan View the other is ArtWeaver in IV you can nominate the resize/file size and AW works very much like PhotoShop 5, both are free and Google will find them.

Cheers - JIm
__________________
FH3 build using very simple tools and a point to point Gain Clone with largish power supply. http://www.jasread.com/fh3/index.html
  Reply With Quote
Old 6th September 2013, 09:29 AM   #2513
bcmbob is offline bcmbob  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Bay City, Michigan
I have that same JC-2 kit and love it. I've never seriously considered another pre since it was built. To my ears it sweetens the sound a bit without adding a lot of coloration. John called it a "straight wire with gain" and it does perform as such. In several other builds I use simple pot attenuation, but where gain is required the Jim's Audio kit excels.

Another item you might want to check out is Uriah Dailey's Resistor Replacer. You can read a review at that thread.


EDIT: RE post 2512 - Take a look at Xnview also. It's been my favorite for several years.

****
Attached Images
File Type: jpg rr2.jpg (17.5 KB, 1226 views)
__________________
Bob M.
"Arrange Whatever Pieces Come Your Way."

Last edited by bcmbob; 6th September 2013 at 09:38 AM.
  Reply With Quote
Old 6th September 2013, 11:29 AM   #2514
davym is offline davym  Scotland
diyAudio Member
 
Join Date: Jul 2013
Location: Under a cloud
Cheers Andrew, will do mate.

And Cheers to you too Bob, funny that we should pick the same pre and power amp kit's. I was directed to that JC-2 kit by a guy on pink fish media's diy section because I had found the one by tubeshunter, it looked quite good so i was asking for opinions about it when someone linked to Jims Audio's version, better spec components etc swayed me.

After I had ordered it however, I did a search on here and came across a thread on the tubes hunter one which later also covered the one I had ordered. Whaleman seemed impressed with the Jims Audio version which was encouraging.

Out of interest, how hot does this version run? i'm wondering if I can fit one inside the same small enclosure I used for my pot in a box preamp, with the transformer in another similar enclosure. I was going to wait and see how hot it got when on for a while but your impression would be nice.

Davy
  Reply With Quote
Old 6th September 2013, 12:18 PM   #2515
bcmbob is offline bcmbob  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Bay City, Michigan
You can get some info and examples HERE.

The pics are of the not yet completed (need pot shaft & cover) separate unit build I'm using now. The R-Core transformer bumps up the quality a significant amount - not drastic but well worth the cost..
Attached Images
File Type: jpg 20130906_080720.jpg (215.9 KB, 1225 views)
File Type: jpg 20130906_080706.jpg (303.1 KB, 1091 views)
__________________
Bob M.
"Arrange Whatever Pieces Come Your Way."
  Reply With Quote
Old 6th September 2013, 12:32 PM   #2516
davym is offline davym  Scotland
diyAudio Member
 
Join Date: Jul 2013
Location: Under a cloud
Looks good Bob! where did you get your enclosure?

The resistor replacer is interesting too, I was going to try Riken's in that position at some point but before I try any mods I need to get some of those speaker posts which have grub screws instead of trying to solder and desolder to those large bolts with a 25w soldering bolt.

That pot looks like the ones I ordered from ebay, the sellers called gigawork in HK. How do you find them?

Edit, ah I see your a fine craftsman when it comes to enclosures too, nice work!

Last edited by davym; 6th September 2013 at 12:57 PM.
  Reply With Quote
Old 8th September 2013, 01:44 AM   #2517
davym is offline davym  Scotland
diyAudio Member
 
Join Date: Jul 2013
Location: Under a cloud
I checked the readings again today as Andrew T suggested.

They started out higher but slowly dropped to.
Left Out = 01.2
Right Out = 02.9

This with a source connected but turned right down, when I raised the volume to roughly 2/3 the readings fluctuated constantly but did not appear to exceed 0.18

Shorting the inputs gave the same readings as I got with source connected but turned right down.

The amp sounds better than I had hoped for or expected, I guess it's ok now.

I'd like to thank the good folks here who helped me out and gave me some very good pointers.

Cheers

Davy
  Reply With Quote
Old 16th September 2013, 08:19 PM   #2518
diyAudio Member
 
Join Date: Jan 2010
Location: Cornwall
Here's my latest, the Mylo amp (named after my my baby)......

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.


This amp uses an LM4780 chip mounted on one of Peter Daniel's boards. Powered with a 120VA 2 x 0-15V toroid.

The A-B switch on the front allows you to select analogue input (A) or Bluetooth input (B). The Bluetooth module I'm using isn't pictured as I blew up my current one, but it attaches to the 6 way dupont connector which can be seen in picture 3 and slots into the oak side to allow it to receive the Bluetooth signal. The heatsink was acquired from an old variable speed drive.

Again, the sound quality from this amp paired with my full range speakers is as good as expected. The LM4780 chip never fails to impress
__________________
Another project of mine: (a very big one at that!)
http://www.mp3car.com/vbulletin/show...5-pimping.html
  Reply With Quote
Old 17th September 2013, 05:53 AM   #2519
diyAudio Member
 
ByronInPortland's Avatar
 
Join Date: Nov 2010
Location: Portland, Oregon
Smile another paralleled LM3886 build

This is a two channel amplifier made from paralleled LM3886's. I used one Chipamp.com board from Brain GT for each chip, then put the boards in parallel. This matches very closely schematic 6.2.1 (PA100-100W parallel circuit) in National's Application Report AN1192. I omitted Cin and Rin is off the board. Rout has one end connected to each board, which can be seen in the close-up photo of the boards. Rails are +/- 34V for, 116 Watts into a 4R load.

The chassis is not the prettiest thing ever. It's my first time working with acryllic. The big hole in the top was from when I had a larger transformer, and will probably be replaced.
Attached Images
File Type: jpg acryllic amp_done.jpg (398.3 KB, 412 views)
File Type: jpg acryllic amp_side view.jpg (160.6 KB, 416 views)
File Type: jpg acryllic amp_top view.jpg (169.1 KB, 311 views)
File Type: jpg acrylic amp_ boards in parallel.jpg (201.3 KB, 295 views)
File Type: jpg acryllic amp under construction.jpg (239.8 KB, 306 views)
  Reply With Quote
Old 17th September 2013, 12:13 PM   #2520
diyAudio Member
 
Join Date: Nov 2003
Location: Connecticut
Default Latest Gainclone - VU meters

This is my latest gainclone amp. This was built with Peter Daniels PCBs and his minimalist design (DC coupled). It uses all Blackgate caps on the amp and power supply boards, Alps Black beauty volume, Vampire gold/teflon RCAs, Superior BP30 output binding posts, 200VA shielded Antek transformer, and all audio wire is shielded teflon litz. Also has solid copper heatsink. I designed a meter PCB for the Weston meters (same ones used on early Levinson gear), and also used that same PCB for a subwoofer output buffer. LED illumination for the meters, with photographic gel filters to look more like incandescent light. I eventually plan to add a JC-2 circuit as input stage. Faceplate is FrontPanel Express, aluminum chassis is from Ango. Knobs are custom made to match early Levinson gear as well.
Mike
Attached Images
File Type: jpg Front view - smaller.JPG (52.2 KB, 435 views)
File Type: jpg top view - smaller.JPG (192.4 KB, 457 views)
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



New To Site? Need Help?

All times are GMT. The time now is 02:35 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2