Help With Potential DIY Project

[dkalsi]

I went with the blue and it looks outstanding.

I used the second formula in the link below scaled down to a quart and didn't lighten it.

JBL Blue Baffle Paint

4313B,

Thank you so much for posting that link. I went ahead with the Behr mix. After I had the technician at Home Depot prepare the paint, I want to inspect it one more before walking out the door. Just like the originator of the Behr paint mix, I too found the color too dark for my liking. Hence, I asked the technician to pour 2oz of white paint to the mix. After adding 2oz of white, the resulting bule was just the blue I wanted for my DIY 4345.

Thanks once agian,
D

[4313B]

Cool!

Yeah, it is darker without the white added; I prefer the darker myself.

[dkalsi]

I am getting ready to veneer over the next few days (hopefully Thursday). Does anyone have any helpful tips before I start the process? More specifically, I wanted to know what I should be worrying about in regards to the tempreture in the room, the humidity, etc. Given the fact that I have brought the enclosure in from the garage - I have better control of the climate.

Just a reminder, I will be using the iron-on method of veneering.

Thanks

[dkalsi]

Have few crossover questions. I am using the above schematics for my DIY 4345 build.

I wanted to know where I can find the circled resistors. I checked Parts Express website for these components but they do not carry these exact values. Do you guys typically wire two resistors of different values in parallel to get actual value, or is it safe to use a 40ohm resistor for as a replacement for the required 39ohm resistor, and 20ohm as a replacement for 18ohm, 16ohm as a replacement for 15ohm, and etc. I am afraid of deviating too much from the schematics.

Lastly, can someone please help me find the 3.OMohm resistors?

Thanks,
Dhar

[grumpy]

An example... with low quantity requirements.

http://search.digikey.com/scripts/Dk...ame=3.0MQBK-ND

Some of the power resistors (if of the same value in parallel)
were likely used that way to dissipate more power.

If they were paralleled but not the same value, I would -guess-
that the value was carefully tweaked (possibly in combination with
more power handling, but then the lower value part would
take the heat).

If there was a parts list, you might get a better idea of what
was intended in terms of wattage and tolerance... or you might
ask the designer nicely (not me), rather than me guessing.

[John W]

The 3.0M resistors that hook up to the 9v battery are used for charge coupling the capacitors. These only need to be the 1/4 watt variety that you find at electronic suppliers like mouser.
If you can't find the values you need at Parts Express, here is a link to another supplier of Mill resistors like you would find in a crossover. You would probably want the 12 watt rating. http://www.soniccraft.com/mills_resistors.htm
Like mentioned, you can also parallel the values. A pair of 39 ohm 12 watt resistors, would be the same as a single 19.5 ohm 24 watt resistor. The doubling in this instance is for the extra power rating.

Do a search on-line and I'm sure you can find a calculator for determining parallel and series resistor values.

[dkalsi]

The 3.0M resistors that hook up to the 9v battery are used for charge coupling the capacitors. These only need to be the 1/4 watt variety that you find at electronic suppliers like mouser.
If you can't find the values you need at Parts Express, here is a link to another supplier of Mill resistors like you would find in a crossover. You would probably want the 12 watt rating. http://www.soniccraft.com/mills_resistors.htm
Like mentioned, you can also parallel the values. A pair of 39 ohm 12 watt resistors, would be the same as a single 19.5 ohm 24 watt resistor. The doubling in this instance is for the extra power rating.

Do a search on-line and I'm sure you can find a calculator for determining parallel and series resistor values.

Thanks for posting John.

I guess my question is whether these values need to be exact or not.

For instance, the crossover requres a 6.8ohm resistor. Would it be okay to use a 7.0ohm resistor as a replacement? And would it okay for me to use 20 ohm resistor as a replacement for the required 18ohm resistor <-- Or should I wire a 16ohm resistor (which they have available) and 2ohm resistor (again, availalbe) in series to get a total resistance of 18ohm?

And Lastly, do I really need the Mills resistor, or can I use Dayton which are 1/3 the price?

Thanks
D

[badman]

I am getting ready to veneer over the next few days (hopefully Thursday). Does anyone have any helpful tips before I start the process? More specifically, I wanted to know what I should be worrying about in regards to the tempreture in the room, the humidity, etc. Given the fact that I have brought the enclosure in from the garage - I have better control of the climate.

Just a reminder, I will be using the iron-on method of veneering.

Thanks

Yeah: Do a LOT of legwork (searching the archives etc) before beginning. The more reading you do, the easier the task. Also, go slowly (naturally, steps where you need to move quick for the adhesive don't apply) and stop and think before each step. A lot of people think they're "In the zone" when they're really just compounding errors (ask me how I know!)

There are a lot of ways to veneer, so I won't get too much more specific. With appropriate care you'll do fine.

[Mr. Widget]

And Lastly, do I really need the Mills resistor, or can I use Dayton which are 1/3 the price?

You can use the Daytons... I don't because resiters are cheap, but I doubt you'll notice a difference.

As for values... I try to end up with measured values that are within 5% of the spec... nice thing about the Mills is that they are almost always spot on. Most of the inexpensive resisters will vary a fair amount.


Widget

[grumpy]

a little more on values...

1) in circuits where there they form a fixed/resistive attenuation pad, using values
that are reasonably close, is probably fair game, especially if followed by an
L-pad in the design.

2) in circuits where the resistors are used to obtain a certain frequency
response shape or Q, I'd follow the recipe as closely as possible, -and-
be sure that the L/R pairs match (or are tightly toleranced). Otherwise,
you may deviate from (lose) the intended system voicing.

I've used the ceramic/wire-wound Daytons... sound fine to me, but the
crappy gold plating means only bend the leads if you have to, or only do it
once.

[Mr. Widget]

a little more on values...

Very good points.


They gold plate the leads? That's pretty cheesy.

A bit OT:

The other day I was digging through my interconnect bucket and got a laugh... I noticed some old "gold plated" RCAs on a cheapo pair had turned rather brownish... I wonder what the percentage of gold their plating was? Or perhaps they advertised their interconnects as gold colored?


Widget

[badman]

Very good points.


They gold plate the leads? That's pretty cheesy.

A bit OT:

The other day I was digging through my interconnect bucket and got a laugh... I noticed some old "gold plated" RCAs on a cheapo pair had turned rather brownish... I wonder what the percentage of gold their plating was? Or perhaps they advertised their interconnects as gold colored?


Widget

Generally that's the brass peeking through, in its lovely oxidized state

[4313B]

Lastly, can someone please help me find the 3.OMohm resistors?

I use 2.2 M ohm myself but anything between 2.0 and 5.0 M ohm will work.

I am using the above schematics for my DIY 4345 build.

I'm working on a new one...

[hjames]

I use 2.2 M ohm myself but anything between 2.0 and 5.0 M ohm will work.
I'm working on a new one...

Thank you, sir ... eager to see your next design!

[dkalsi]

I use 2.2 M ohm myself but anything between 2.0 and 5.0 M ohm will work.
I'm working on a new one...

Oh noo? - new crossovers? Should I cancel my order for the parts corresponding to the above schematics?

Thanks,
D