Need help with Teledyne PB stereo console driver upgrade

[fixthedoor]

Re: Need help with Teledyne PB stereo console driver upgrade

Cross-over parts list:

(2) 255-036 Jantzen .50 mH 20 AWG coil
(2) 255-028 Jantzen .30 mH 20 AWG coil
(2) 027-424 Dayton Audio DMPC-6.8 6.8 uF 250V Polypropylene Cap
(4) 027-340 10 uF 100V Electrolytic Non-Polarized Crossover Cap
(2) 004-8 Dayton Audio DNR-8.0 8 ohm 10W Resistor
(2) 004-9.1 Dayton Audio DNR-9.1 9.1 ohm 10W Resistor

I assumed "NPE" was an acronym for Non-polarized electrolytic
Will the 9.1 ohm resistor work? PE doesn't have a 9 ohm. The 9.1 has a claimed tolerance of 2%, so depending on where it actually measures it could fall in the territory of a 9 ohm (again, more assuming on my part)

Cross-over schematic:

[Chris Roemer]

Re: Need help with Teledyne PB stereo console driver upgrade

Looks just like MY drawing!

The 9 ohmer will be fine.

The most critical cap (value-wise) is the 10uF parallelling the LP coil, 'cause it's acting as a notch. But I'm guessin', whether you use Dayton's npes or polys, it'd measure about 10.2uF, which is fine.

[fixthedoor]

Re: Need help with Teledyne PB stereo console driver upgrade

Awesome! Hopefully parts will be ordered today.

Question for you. I was thinking about this thread yesterday and you said, "rude and crude." I'm curious what you meant by that.

[kenrhodes]

Re: Need help with Teledyne PB stereo console driver upgrade

I think that by rude and crude he meant that this wont be a high end build and wont need to have fancy cabinets or crazy woodwork.
I think the design they gave you will sound great, way better then the stock stuff in there now.

[fixthedoor]

Re: Need help with Teledyne PB stereo console driver upgrade

I was thinking it was something along those lines. I hope my post didn't come off wrong, as I'm stoked to be working on this and to have received Chris's help. It's brilliant! The progress so far has been fun and the wait for parts to come in is going to test my patience.

[fixthedoor]

Re: Need help with Teledyne PB stereo console driver upgrade

Parts have been received and progress made!

We gutted the insides, leaving only the turntable. I took rough measurements before removing the amp/receiver and used painter's tape to make a couple reference marks. The bottom had a real thin panel (<1/8") that was bowing and pretty much useless. Another panel will be installed with some cross-bracing to provide support and attachment points for the speakers. I'm still planning on using a combination of rubber grommets, springs, nuts and bolts to help isolate the speaker boxes from the rest of the cabinets.



With everything out of the way I used a sliding t-bevel gauge to get the angle of the front of the cabinet. I then adjusted my chop saw according to the gauge. A scrap piece of wood was cut and tested in the front corners to verify I had the angle correct. Fortunately it was a nice and neat 100*. This measurement is needed for the side panels and the left and right sides of the new baffles. Determining the angle at this point was only to satisfy my curiosity. Since the new speaker box will be independent of the console cabinet (except 4 mounting points) I'll determine the correct angle from the tops and bottoms of the speaker boxes once they are cut.

To help map out the footprint of the speaker boxes, I cut a template from a piece of cardboard. To do this I had to determine my clearances. 1" from the sides to clear console cabinet bracing; 3/4" from the front to clear speaker grill cloth (1/4", mesh + wooden weave) and it's frame (1/2" gonna reuse the existing and cut out the middle); 1/8" from the back brace.

After one mis-measurement, I forgot to subtract clearances, the template was cut out and checked. I also took some notes on the template for later reference.



One my favorite tools is a combination square. I used it to help extend reference points from the cabinet. In the picture, I aligned my measuring tape to it get an accurate front to back measurement. A longer square would have been easier.



The grill cloth came of easily and only slightly out of shape. I have them resting between the old baffles to help keep them flat.



One of the baffles:



The coaxial speaker is a jensen 6x9 that had been installed at some point.

I was also able to lay out the crossover and prep a piece of 1/4" ply for the board. Connections will be made and soldered at each hole. I will also put a little hot glue in the hole to fill the voids and create a little mushroom top to help hold the components in place. I don't remember where I saw this, but it worked well for the OS crossovers I built.

[Chris Roemer]

Re: Need help with Teledyne PB stereo console driver upgrade

Looks good to me.

[fixthedoor]

Re: Need help with Teledyne PB stereo console driver upgrade

Update:

Spent yesterday cutting and putting together the boxes, then finished the crossovers and mounted everything this morning. I've been listening to them since

I used 1/2" scrap plywood (from a disassembled cabinet) for most of the box and 3/4" scrap plywood for the front baffle. Since the boxes will be hidden I am not too concerned about how they look, which is good cause the plywood is in poor shape and would take some work to look decent. I do plan on sanding them down and spraying a couple coats of paint to help hide them though.

I also need to provide some support on the insides of the boxes, but I couldn't wait to rock these things! So far I'm pretty happy and almost don't want to put them in cause they beat the hell out of the pioneer bookshelves I'm currently using in my garage.

Anyway a few pics:

I put removable backs to make installing in the console easier.



The crossovers



Here they are pumpin the jams for clean up



Thanks Chris!

[fixthedoor]

Re: Need help with Teledyne PB stereo console driver upgrade

Chris,

When you said "...lined..." in your first post, do you mean bottom, sides, top and back? What would you suggest I use, the egg crate foam?

Currently I only have a bit of batting (I think it's actually for quilts or blankets) along the bottom.

[Chris Roemer]

Re: Need help with Teledyne PB stereo console driver upgrade

Yup, I use Wal*mart "mattress topper".

1/2" ply SEEMS fairly thin. You might need several wall-to-wall braces to stiffen things up (like, 3/4" dowels or 3/4" sq. stock). I'm glad they sound good to you so far.

[fixthedoor]

Re: Need help with Teledyne PB stereo console driver upgrade

K. I listened to them for about 8 hrs yesterday and it will interesting to note the changes with the wally world topper. The tweeter definitely settled down, but the lows remained pretty subdued. A mic for testing is in my future...just don't tell my wife.

Yeah I am planning on stiffening things up. I have plenty of 3/4" scrap that will do the job, maybe I can scrounge up some 1/4" ply to laminate some of the insides. At least on the bottom since that's where they will attach to the console.

[fixthedoor]

Re: Need help with Teledyne PB stereo console driver upgrade

A small update. I laminated 1/4" board on all 1/2" sides, added some bracing, installed insulation, prepped for paint and applied primer. My dad just had surgery so in the interest of keeping this a father and son project, progress has stalled.

I used unfaced batts to line the walls. They were very thick, so I had to split them into more manageable pieces. This lead to varying thicknesses from one side to the other and different quantities of insulation in each speaker. I'm not happy with these inconsistencies, so once we get going again I'll pick up some of the mattress topper.



To laminate the 1/4" I used contact cement, and to hold the pieces in place I used a combination of 1/2" screws, finish nails and paperweights (E7 heads)



As much as I could I tried to increase the thickness on the inside of the cabinets as much as I could, but a couple areas had very tight clearances so thickness was increased on the outside. Fortunately, I have plenty of clearance inside the stereo console cabinet so the speaker boxes will still fit. I also used closet rod for side to side and top to bottom bracing. Glue and countersunk 2 1/2" drywall screws hold them in place.



I used a 3/8" round over (biggest I have) and a 1/4" everywhere else. Any exterior screws were removed and their holes filled. As you can see I used a generous amount of filler.



I power sander with 220 made quick work of sanding duties.



I applied several coats of primer, letting each coat bake in the sun. The primer is a PVA drywall primer which goes on very thin so I wanted to build up a good base before sanding again. The cell phone pics hide the defects that made themselves known. Fortunately sanding will take care of most of them.





I have listened to them quite a bit and it's been fun hearing the differences before and after the modifications. In the future I'll be sure and take care of laminating duties before assembly to achieve rabbet joints all around. So far they have been powered by an LP-2020, a Pioneer SX-550, and a Denon AVR-889, and at this point I am not too optimistic about using the stereo console's amp.

These things can put out some bass! I used them for my wife's birthday party a couple weeks ago and for what it's worth, they impressed. I do think something is missing though, which maybe because I cut the port 3/4" too long (thickness of the baffle was not taken into consideration when I cut the ABS pipe). I still have to seal the back panel and around the speakers as well. This also lead to another question, which I have not researched at all, but could I use the Audyssey mic from my Denon and Tascam US-1641 audio interface to record measurements?

I've loved every minute of this journey so far. It has been far from ideal, but overcoming problems, figuring out procedural issues and finding out tool shortcomings has been fun. Two immediate issues are, I need to have more patience (one reason I use fasteners in addition to glue) and more clamps! With all that said I'm seriously thinking of rebuilding the boxes out of 3/4" stock and tweaking the design a little.

[fixthedoor]

Re: Need help with Teledyne PB stereo console driver upgrade

A resistor in series with the tweeter will cut it down.

Each side needs 7 components:
0.50mH #20 coil
0.30mH #20 coil
one 6.8uF and two 10uF npe caps
one 8ohm and one 9ohm resistor

High pass (on tweeter) will be a 9ohm (attenuation) resistor in series with the 6.8uF cap, then a shunt coil (the 0.30mH - to ground) next to the tweeter. The tweeter gets connected reverse polarity.

Low pass uses a 10uF cap in parallel with the 0.50mH coil, in series with the woofer's "+" terminal
Next to the woofer is a "Zobel like" circuit using the 8ohm resistor and 10uF cap, in series with each other, but the circuit is in parallel with the woofer's terminals.

Chris Roemer Did this crossover have BSC? I'm finally getting around to building proper enclosures, but want to change dimensions and use as shop speakers. Was planning to make them more narrow and tall. They'll end up on a large, 2' deep shelf so I have flexibility with dimensions. Just wondering how much latitude I have when redesigning the enclosures. Baffle will end up about 28" from the wall, which is corrugated metal. There's about a 5" difference between the peaks and valleys (prefab building).

[Chris Roemer]

They'd probably end up with around 3-4dB of BSC on an 11" wide baffle.

[fixthedoor]

They'd probably end up with around 3-4dB of BSC on an 11" wide baffle.

Cool, thank you. That's about what I was thinking. My ballpark was 10"-11" wide.