JLM AUDIO

Smasha wrote:I'd love to make those monitors but I'm dumb as doggy doo.


I'm gonna save and get the stuff and stress about it later.


What's that big round thing in the middle Chrisp?

Wow just had a look.

You get all the stuff including led in the kit-awesome.

I've been using an old Pioneer contempo mini hifi as monitors odear.


Stop laughing at me.

Mate, if I can do it you can too. See build thread.

I'm thinking of doing a stereo amp, but I'm concerned about the left/right level matching when used with a +/-20% volume potentiometer. Any thoughts?

Hi ChrioN

Your concern is completely understood and, for important applications, entirely justified.

The solution is to go for a stepped attenuator rather than a pot. This is a multi-position switch build with 1% resistors (or even 0.1% SMD resistors), and provides accurate tracking across all settings.

The downside is that volume changes in steps, rather than tracking smoothly across the range. If this is a problem, you can add a trim control (the pot tolerance in this instance is less critical because the range it has to cover is relatively small).

If you have a look at the schematic for the JLM 1290, you'll see this stepped gain / trim combination in use.

Lots of great information and products on this topic at:
http://www.goldpt.com/diy.html

(No, I don't work for them)

Thanks for the reply Chris. I would avoid stepped attenuators if I can.

I don't know what a regular intergrated amplifier uses for volume control.
Is that an ordinary +/-20% potentiometer? If so, I should be more than fine.
I ain't gonna use this amp in mastering situations anyways, but I would not be happy if I found out that all my mixes are leaning left

if you want a pretty decent locally available stereo pot. RS has these :

http://australia.rs-online.com/web/sear ... &R=2199130

they are spec-ed for 2dB gang error, but generally i find they are better than this.

R

I've finally got some money to try this kit with the Decibel Jordan kit.

Bloody sweating with horror as I don't have any understanding of electronics.

Some of the stuff I read in the posts above just goes right over my head.


Anyone have a step by step guide?

What extra stuff do I need besides the jlm kits to power them up?

Was gonna get the fully made kits but they are 4 times the price.

Why is that?

Mick@ITC wrote:

Smasha wrote:I'd love to make those monitors but I'm dumb as doggy doo.


I'm gonna save and get the stuff and stress about it later.


What's that big round thing in the middle Chrisp?

Wow just had a look.

You get all the stuff including led in the kit-awesome.

I've been using an old Pioneer contempo mini hifi as monitors odear.


Stop laughing at me.

Mate, if I can do it you can too. See build thread.

Mate ,I'm Colonel Klutz.

smasha, you've seen the schematic?
besides the module fully loaded up, you need a suitable mains transformer and a bridge rectifier. The transformer needs to connect to the mains supply preferably via a switch, fuse and IEC type mains socket.
You need to be confident what you are doing at this end of proceedings.

The choice of transformer is governed by the power you are after from the amp, but a 25V + 25V is a good start.

then there are extra features like a volume control and power on led.

If the drawing showing the hookup on the JLM site doesn't make immediate sense to you, it is probably best to get some hands on advice....just so you don't kill yourself!

Rob

Yeah, I might leave it.

No use getting all this stuff if I have no idea about how things work.

Haven't really got any work space here to do it

Smasha

If you are not proceeding, do you want to sell you Jordans?

PM me if so

woah!!! smasha exists!!

chrisp wrote:Smasha

If you are not proceeding, do you want to sell you Jordans?

PM me if so

Haven't bought any yet.

Hey Paul I'm still hanging around.

Should be gigging at The Evelyn soon.

They banned me at Melband LOL.

P.S. Was gonna buy some KRK VXT 4s and later get a sub from OS.

OTT pricing here.

I seriously would've bought this kit bit I'm too dumb with a soldering iron.
I bought some Dynaudio bm5as instead.
Broeke because of it but music means alot to me.

More than the dumbarses at Melband.

I've been drumming for 36 years but tell the tossas at Melband that!

The music scene died in the 80s anyway.

..and now my bros(drummers ) are extinct.

Ermz lol .

Trying to find the greatest monitor lol.
It's really about the musiuc m8 not the technial aspects .

So many tossas in the world today!