Mic preamp kit for speaker testing

[Kyle]

Has anybody tried this microphone preamp kit? I need to build one for testing speakers, and it seems like it may be OK. Does anybody know of any other kits available that may be cheaper?

http://www.highefficiencyloudspeaker...amplifier.html

[Vikash]

Brian and I are in the process of developing dedicated mic preamp PCB's and kits specifically for this purpose. They will be of superior quality to those currently on offer: Mic Preamp PCB kit offering (measure FR etc)

[Hornlover]

What makes the one you are working on superior? Have you built the HEL mic preamp?

[kleung]

what is the ETA of this product?

[Kyle]

I built the kit that is on the HEL site. I can recommend it for anyone looking for a good all-in-one source. I had built a couple of the Wallin units previously, and they worked ok. When I needed another one, I found the HEL kit, so thought I would give it a try. It works better than the Wallin version, with about 1/3 the wideband noise. Also, the power drain is only about 1/4 the Wallin unit (about 2.5mA), so my battery lasts a lot longer. The pc board is tough FR-4, and all the resistors are 1% metal film. The caps are all tantalum or ceramic, making them more stable than the electrolytics on the other version.

[jleaman]

You mean like this **** poor layout that dave gave me. UGG stupid paper over lay.

[GregoryD]

I have built and use the HEL preamp and I must say that it is a very good unit. The layout of the board is excellent... very well thought out. The assembly is straight forward. Although not stated, the gain of the preamp is 20dB (10x). I find this ideal when using JustMLS for 1 Meter measurements. You will have to drill the 3 holes in the plastic case if you purchase the unit with the case. A few years ago I built 3 mic wands. They are fairly easy if you have a magnifier to assist you when you solder the leads to the capsule. All 3 of my wands have virtually the same response profile and they seem to follow the response shown on the Wallin site. If you are considering this kit, I would recommend getting one of the options that includes all of the parts. Finding and ordering the right parts is not worth the extra effort, IMHO.

[Mark Striker]

I can recommend the HEL preamp as well. Its simple for anyone with rudementry skills to assemble. You will want to get the full kit. It will save you money in the long run, unless maybe all parts can be gotten locally, and you dont have to pay shipping from Digi-Key and Mouser.

[DonoMan]

20dB is 100x, not 10x. 10x is 10dB.

[wintermute]

Originally posted by Kyle
I built the kit that is on the HEL site. I can recommend it for anyone looking for a good all-in-one source. I had built a couple of the Wallin units previously, and they worked ok. When I needed another one, I found the HEL kit, so thought I would give it a try. It works better than the Wallin version, with about 1/3 the wideband noise. Also, the power drain is only about 1/4 the Wallin unit (about 2.5mA), so my battery lasts a lot longer. The pc board is tough FR-4, and all the resistors are 1% metal film. The caps are all tantalum or ceramic, making them more stable than the electrolytics on the other version.

Sounds like you made the original wallin preamp. The MK II version uses a higher quality op-amp which has a current draw of 1.44mA (not sure what the overall circuit draw is).

Just thought I'd point this out so anyone considering the Kit that Brian and Vikash are offering doesn't get the wrong idea on it's performance.

comparison of the two op-amp versions from erics site attached.


Tony.