Some things you might be interested in

[Vetsen]

Harbor Freight has some good deals.

Chasis punch set

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=91201

Sound pressure level meter

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=92282

I have not tried these yet but they are a great bargain.

Vetsen

 

[strangeandbouncy]

SPL meter looks like the one Tandy(RadioShack) used to sell. I have used it pretty much daily for 19 years to monitor my playback level. Not much difference between this and the Bruel & Kaer, except a few hundred Quid!

Andy P

 

[dpaton]

[quote author="strangeandbouncy"]SPL meter looks like the one Tandy(RadioShack) used to sell. I have used it pretty much daily for 19 years to monitor my playback level. Not much difference between this and the Bruel & Kaer, except a few hundred Quid!

Andy P[/quote]
ACK! I wish that was even close to true.

The B&K I use from time to time has a consistent calibration. 90dB at 20z registers the same as 90dB at 1K and the same as 90dB at 20k. The Radio Shack meters I use can only dream of being this accurate. The correction factors I use are as follows:

Freq   dB
10     20
12.5   16.5
16     11.5
20     7.5
25     5
31.5   3
40     2.5
50     1.5
63     1.5
80     1.5
100    2
125    0.5
160   -0.5
200   -0.5
250    0.5
315   -0.5
400    0
500   -0.5
630    0
800    0
1000   0
1250   0
1600  -0.5
2000  -1.5
2500  -1.5
3150  -1.5
4000  -2 
5000  -2
6300  -2
8000  -2
10000 -1
12500  0.5
16000  0
20000  1

They were developed against a traceable B&K rig and averaged from 9 different RS meters. Every single one was a little different, but this curve should get your analog RS SPL meter to +/-1dB accuracy over most of the noted range. If you really need more precision, you need to find a calibration station and generate your own curve. You'll also need to remember it varies with temperature, so these numbers are only valid around room temperature (~72F).

-dave

 

[strangeandbouncy]

Erm , . . . .


I meant for what i was using it for, ie explaining to idiot dj clients why I wished to monitor at < 90db for protracted lengths of time. My comment was meant to be a bit flippant, and that's that! I cannot comment on its test-bench accuracy. i can comment on the state of my ears after 20 years in this business.

Nothing else intended!

Andy P

PS I can still hear bats, and i am 40 this year.

 

[Vetsen]

Oh yea, here is another item us DIY etchers can use

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=90757

A bit more expensive but if you are making lots of PCBs...


Vetsen