Need help with Teledyne PB stereo console driver upgrade

[fixthedoor]

Hey all! I recently delved into speaker assembly with an OS build from PE (which is how I ended up here) and I already have a build list going, including special requests.

After hearing the OS's (many thanks to Paul and his efforts) my dad and I wondered what we could do to a Teledyne PB stereo console he has. This leads to the question of, what kit or DIY build should we use?

Budget is $200, but not set in stone, and we have plywood for the cabinets. I'm going to have to investigate the guts of the console because the model number and power abilities are not clearly visible. Depending on what I find a separate amp is an option. The goal is to keep the outside stock with changes happening to the guts.

Top of console with lid open



Looking through the back toward the front of the console



For reference, the large speakers are 6x9. I lost the measurements I took so I'll have to post the interior dimensions later.

The speaker baffle can be easily removed (from the inside) and replaced to accomodate whatever we decide to do. There seems to be plenty of room for (2) cabinets inside the console. The existing baffles (2) are quite large, covering about 70% of the front of the cabinet. This leads me to make an uneducated guess that an in-wall or on-wall design should be used.

Another issue is that the front baffles are angled (I'll have to take a picture of the outside) and I will only be able to separate the left and right as much as the console will allow. This leads me to my next uneducated guess that we need something with good off axis response.

The console has sentimental value for my dad, so we want it to sound good, but since it's not an ideal situation, we only want it to sound as good as $200 (give or take). So what say yee?

Thanks.

[fixthedoor]

Re: Need help with Teledyne PB stereo console driver upgrade

Interior dimensions of the console are roughly 34.5" W x 18" H x 14" D (@ left and right sides) & 17" D (@ Center). Checked the inside of the unit and still can't find the model or amp info. The bottom of the receiver assembly has AUX, Phono and Tape Out.

With my limited knowledge I figure I can take the existing amp out of the equation a couple different ways.

1. Hook up an amp (with volume control) to Tape Out and then put the new volume pot somewhere easily accessible. New speakers would be directly connected to the new amp.

2. Utilize existing volume control and install amp after volume pot and connect new speakers to new amp. I think I am missing something here though...

A couple more pics

[Chris Roemer]

Re: Need help with Teledyne PB stereo console driver upgrade

Well, this is kinda crude & rude, but your Dad will love it.
Use the L & R one/thirds for trapezoid shaped vented boxes of about 1.7cf each. The middle one/third will stay open-backed with the electronics.
The right side will be a "mirror" of the left.
Use a 275-070 "Silk Dome" for a tweeter mounted centered in the left "slot", with the center of the dome 1/2" lower than HALF the WIDTH of the "slot".
Mount a 3"id port tube to its right, centered in that middle slot.
Use Dayton's 295-310 8" woofer centered on the "post" between the tweeter and port "slots", as high as it can comfortable go.
I'll work out the length of the port tube (could be a cardboard 3"id mailing tube), and a 2000Hz crossover for you if you like this idea.
These 2 "outside" boxes will need to be lined, and have removable back, so you can get inside.

You MIGHT want to actually build 2 (trapezoid shaped) stand-alone (outside) boxes, and somehow screw them to the top, bottom, and side.
I'm not sure, but you certainly don't want to have anything buzzing in there.

[fixthedoor]

Re: Need help with Teledyne PB stereo console driver upgrade

Thanks for your response Chris. I don't think I understand your layout. Standing in front of the console, staring at the front left side of the console, I picture the woofer up high. The tweeter to the lower left of the woofer (about half way up the baffle, existing baffle is 16" so this would be 8" up) and the port to the lower right of the woofer (also about 8" up). I'll try and post a drawing tomorrow if that would help.

Yeah I would have to do 2 separate cabinets to get them in the console.

I figured out the dimensions for 1.7 cu ft cabinets, it's gonna be tight! I'm gonna check it out tomorrow to see if it clears everything.

At the moment I'm planning on using 3/4" ply for the cabinets.

[Chris Roemer]

Re: Need help with Teledyne PB stereo console driver upgrade

No.

My description is just of the left half, as seen from the front. Those 3 vertical openings are what I call "slots" (don't know their dimensions, but look to be about 3"w x 14"h). Tweeter near top of left slot. 3" port to its right in the middle slot, at top. 8" woofer as high as it can go BENEATH the tweeter and vent, centered on the "post" between the left and middle slot.

"Use a 275-070 "Silk Dome" for a tweeter mounted centered in the left "slot", with the center of the dome 1/2" lower than HALF the WIDTH of the "slot". BY THIS I MEAN IF THE SLOT IS 3" WIDE, THEN THE CENTER OF THE DOME SHOULD BE 2" DOWN FROM THE TOP OF THE SLOT - i.e. "center of dome 1/2" lower than HALF the slot's WIDTH - so if slot is 3"w, then half = 1.5", PLUS 1/2" = 2" down to center.
Mount a 3"id port tube to its right, centered in that middle slot.
Use Dayton's 295-310 8" woofer centered on the "post" between the tweeter and port "slots", as high as it can comfortable go.

I think you get what I was saying, but flopped the layout top to bottom. I'd probably NOT flush mount the drivers, but surface mount them to the front of your removeable boxes, and probably ADD A SPACER all around the box front so you can push them up against the grill cloth w/out crushing in the silk dome on the tweeter.

Also, you need a way to isolate these boxes from the cabinet walls so you don't get any buzzing. Felt, foam rubber sheets, or old carpet pieces?

Also, these will go down to 30Hz, so the turntable won't track anymore (maybe you'll just keep it in there for looks?) due to bass vibrations.

[fixthedoor]

Re: Need help with Teledyne PB stereo console driver upgrade

The blind man picked up his hammer and saw. I got it, thanks for clarifying.

Yeah I was wondering about the tracking when I checked out the woofer. I hope that I'll be able to isolate it enough because the turntable is part of the allure. A couple different methods of isolating the boxes I thought of are:

1. Top and bottom rails lined with carpet and removable braces across the back, also lined with carpet. The boxes would fit snuggly in the rail system so as not move around when the console is moved. No fasteners would be used to secure the boxes to the rails, it would be floating, if you will.

2. Rails only at the bottom of the console, with the boxes being secured to the rails with through bolts at 4 locations. 3 rubber grommets would be used to keep the nuts and bolts from contacting the wood. Caulking would be used for the holes.

I'm liking #2 seems like it would be easier.

The idea of an 8" woofer is awesome BTW. I had only been considering kits/builds with smaller drivers.

I'm going to check the console out this afternoon to try and sort the box dimensions out.

[fixthedoor]

Re: Need help with Teledyne PB stereo console driver upgrade

Would 1.66 cu ft work? The turntable extends down into the console about 1.5". I could get 1.7 but it would require a more complex box. Here's what I have so far:

The pink lines indicate the console's front slots





Took the baffle off to measure the slots. The grill cloth is mounted to the baffle so it looks like we'll have to replace that.

[michiganpat]

Re: Need help with Teledyne PB stereo console driver upgrade

too bad the aura NS6's are gone...Don'a Aurbacs (in TM or MTM arrangement) would have worked pretty good in here.....

what about looking at adapting Paul's Hitmakers?

[Chris Roemer]

Re: Need help with Teledyne PB stereo console driver upgrade

If you're careful, you should be able to reuse the grill cloth on YOUR baffles.
I'd prefer that the center of the tweeter's dome be at least 1/2" more away from the top of its slot than its distance to the sides. AND I'm talking about (once its in place) the distances to the edges of the circle-top opening in the woodwork on the front of the cab (not as concerned with what's actually going on from the back-side).

I'd prefer you to show on your diagram the outline shape of the 3 square-bottomed / circle-topped slots, and how you intend to line the drivers up with those. I'm pretty sure that your distances between the 3 slots should be the same as each other. By your dims, they're all over the place.

Right idea though. And 1.66 cf will be good enough.

[fixthedoor]

Re: Need help with Teledyne PB stereo console driver upgrade

I'll have to see if I can pull the grill cloth off without damaging it. Hopefully the glue is brittle enough.

The center of the tweeter will be about 3.5" from the arc, because the top tray (where the turntable and controls are) extends below the arcs:



Yeah the dimensions look a little screwy. Each is a measurement from the left, it's easier for me when I go to layout the baffles. Otherwise, if stack the measurements I'll end up off somewhere.

From the left (measuring from the inside) it's 13/16" to the first slot.
First slot: 2 15/16"
Column: 2 5/8"
Second slot: 2 15/16"

Pat - I didn't consider those for whatever reason, but I'm sold on the 8" woofer. When I think of how the console will be used, the idea of an 8" woofer fits perfectly.

[Chris Roemer]

Re: Need help with Teledyne PB stereo console driver upgrade

Got that. So your dwg from post #7 DOES look good to me.
I like the tweeter's distance down, and I NOW see that you DO have the woofer centered on the "post" between 2 slots. That's how I'm envisioning it.

The 3" port tube should be 10" long.

[michiganpat]

Re: Need help with Teledyne PB stereo console driver upgrade

dumb, out of the box idea, since the opening between the slots are ~3".....

a line of 4 Aura NS3's arranged vertically wired in series/parallel

http://www.madisoundspeakerstore.com/approx-3-fullrange/aurasound-ns3-193-8a1-3-black-cone-wide-range/

quick playing with an online box simulator shows ~5L per driver tuned to 51hz will give an F3 in the 40's....maybe couple that with a hivi T-20-8

http://www.madisoundspeakerstore.com/hi-vi-soft-dome-tweeters/hi-vi-t20-8-20-mm-textile-dome-tweeter-8-ohm/

or $15-20 vifa....

that would be $125.50 in drivers, and shouldn't 4 80db/1w/1m drivers in series-parallel net ~86db efficiency?

that way you might not end up with as many weird reflections and response due to portions of the woofers being covered by the columns...

[Brian Steele]

Re: Need help with Teledyne PB stereo console driver upgrade

My idea: Consider a 2.1 system to fit inside that cabinet, i.e. use a separate cabinet to hold the "subwoofers". Look into a PPSL design with two eights - you can point the slot for the PPSL out through one of the lots on that cabinet's front baffle. IT will also be a LOT easier to isolate that subwoofer from the rest of the cabinet, so the impact of vibrations from the bass on the turntable is minimized.

[fixthedoor]

Re: Need help with Teledyne PB stereo console driver upgrade

Thanks for the input guys but I'm sticking with the 8" woofer and the 1 1/8" tweeter. I don't understand all the numbers just yet, but from what I've read this seems like a safe way to go. The woofer behind the post is what is, whatever we do will be a sizable improvement so we're ok with the trade off. Regarding the vibrations, it's definitely a problem and will take some trial an error to sort out.

We're sorting out the amp situation now. If we pull the trigger on the amp we're just going to connect to the Tape Out. This is what we're considering:

Pre-Amp

http://www.electronickits.com/kit/complete/ampl/k100.htm

Amp

http://www.parts-express.com/pe/showdetl.cfm?partnumber=320-303

Problem is we'll end up with 3 power cords coming from the console.

Chris - Don't mean to bug, do you know what components I would need for the crossover? (I think we're ready?) I'm putting together a purchase list. I'm going to take a look at the console again today and run some new dimensions. My depth measurements are tight, not leaving much room between the baffle and front of the console (I forgot the drivers won't be recessed). If I hold the baffle back a little we'll end up closer to 1.6 cu ft. I'm pretty sure I can make this up by extending the bottom of speaker boxes. They would have to be notched and it would make mounting a little more difficult though.

A question I had was, how is the sensitivity determined? I see the DC28F-8 has an SPL of 89 and the DC200-8 has a sensitivity of 88.

I'm thinking we could wait on a new amp and see what the existing amp can do with this combo.

[Chris Roemer]

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.