diyAudio - Entries for December 2013
Go Back   Home > Forums > Blogs > rjm

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
Old

Hakko FX-950

Posted 20th December 2013 at 10:29 AM by rjm

Earlier this year I had a really, really bad experience attempting to get a new soldering iron. This time around I made my purchase through a reputable Japanese online retailer, and am now the proud and happy owner of a Hakko FX-950 soldering station.

Its an analog unit, and was discounted quite a bit as a result. Personally I'm happier with a rotary dial temperature control anyway.

This thing rocks! I've dragged my heels on getting a decent iron for so long its ridiculous. In my defense, I could always borrow a semi-decent one from work, so the pressure to buy my own was not as great as it otherwise might have been.

Top five reasons to spend the extra cash:

1. 70W, variable, closed loop temperature control. As much heat as you need, whenever you need it: the feedback loop means that the power is proportional to the conductance load: the tip will not cool down when heating up a large thermal mass.

2. Heats up to...
Attached Thumbnails
Click image for larger version

Name:	DSC_0302 1000.jpg
Views:	93
Size:	226.1 KB
ID:	1194   Click image for larger version

Name:	DSC_0304 1000.jpg
Views:	90
Size:	191.7 KB
ID:	1195   Click image for larger version

Name:	DSC_0305 1000.jpg
Views:	133
Size:	205.8 KB
ID:	1196   Click image for larger version

Name:	DSC_0310 1000.jpg
Views:	158
Size:	246.9 KB
ID:	1197   Click image for larger version

Name:	DSC_0325 1000.jpg
Views:	190
Size:	213.1 KB
ID:	1198  

rjm's Avatar
rjm
diyAudio Member
Posted in The Lab
Views 748 Comments 4 rjm is offline
Old

Upgrading the Sapphire headphone amplifier (photos)

Posted 17th December 2013 at 10:10 PM by rjm
Updated 20th December 2013 at 10:14 AM by rjm

Straightforward transplant. Out with the old (anyone want them?) in with the new. Re-used the OPA134 op amp and my dog-eared pair of 0.47uF Multicaps.

On powering up I discovered that with the specified 10 ohms in R9,10 the output bias current was upwards of 200 mA and things were getting a bit toasty. I paralleled a second 10 ohm resistor, dropping the resistance to 5 ohms and dialing back the output bias current to about 70 mA. Latest schematic revision has R9,10 values edited to match.

Currents stable. Heatsink temperatures around 50 C. Output offsets around 15 mV. No noise or hum.

Presently giving it some burn in time.
Attached Thumbnails
Click image for larger version

Name:	DSC_3577 1000.jpg
Views:	283
Size:	398.6 KB
ID:	1180   Click image for larger version

Name:	DSC_3558 1000.jpg
Views:	301
Size:	303.2 KB
ID:	1181   Click image for larger version

Name:	DSC_3579 1000.jpg
Views:	223
Size:	306.7 KB
ID:	1182   Click image for larger version

Name:	DSC_3588 1000.jpg
Views:	183
Size:	311.2 KB
ID:	1183   Click image for larger version

Name:	DSC_3589 1000.jpg
Views:	142
Size:	375.9 KB
ID:	1184  

Click image for larger version

Name:	DSC_3592 1000.jpg
Views:	718
Size:	388.8 KB
ID:	1185   Click image for larger version

Name:	pcb-sapphire-20f3-sch.png
Views:	302
Size:	37.3 KB
ID:	1186  
rjm's Avatar
rjm
diyAudio Member
Views 522 Comments 0 rjm is offline
Hide this!Advertise here!

New To Site? Need Help?

All times are GMT. The time now is 11:32 AM.


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