My frugal reference loudspeaker with Philips Fullrange.

[rocket_sled]

Very Innovative

 

[t.antony]

Thanks everyone, I will try my hands at assembling the winder tomorrow. Almost the whole day spent at the carpenter's shop today and finally got the enclosures. Here is couple of shots.

The carpentry is not good as I expected, anyway the dimensions are somewhat within tolerance limits . I need to take these back again for finishing after fixing ports, filling gaps, lining the inner walls etc.

Cheers!

 

[keith_correa]

Not bad at all! These are going to look sharp after finishing up. :clapping:

 

[t.antony]

Not bad at all! These are going to look sharp after finishing up. :clapping:

I like the finish of GeorgeO's MTM - Thinking of something similar.

Here is a pic I took at the last HFI meet.

 

[t.antony]

Finally the coil winder is ready. My wife deserves credit this time for sparing me from the endless chores at weekend. I used up two full days for DIY .

The second pre-tensioner (the pvc tube below the winding mechanism) give a good workable tension to allow close and tight winding. I used 19 gauge for trial run and it seems to be easy to work with. The counter is fixed loosely to compensate for the wobble due to misalignment.

Now it's time to get some good bobbins...

Regds.

 

[anilva]

Anthony,

This is outstanding! So impressive. Hats off to you! Tell your wife that she is helping a genius in a good cause.

Cheers.

 

[t.antony]

Anthony,

This is outstanding! So impressive. Hats off to you! Tell your wife that she is helping a genius in a good cause.

Cheers.

Thanks for the generous comments. In the past, the cost and complexity of obtaining inductors was a major reason for putting off projects. Hopefully this contraption will give me more freedom in DIY.

Regds...

 

[anilva]

The other option I was toying around with was to buy a used coil winding machine spending 1-2K. The new one costs around 10K.

I agree. Not being able to do good inductors is a big handicap.

Cheers.

 

[t.antony]

The other option I was toying around with was to buy a used coil winding machine spending 1-2K. The new one costs around 10K.
Cheers.

I saw manual coil winding machine at a by-lane in SP road - close to Vishal Electronics. The asking price was around 2k. It's a bit bulky and probably needs a dedicated table. The good thing was that it had couple of lathe type fixtures for holding the coil - very useful in winding the coil with the former in place and then fine tuning the inductance with an LC meter without taking the coil off the winder.

Regds...

 

[t.antony]

Yesterday night did a small surgery on the fullranger prior to fixing the phase plug. While the dust cap is being cut apart, It exposed a copper surface on the pole plate! I wasn't expecting to see copper inside the motor of a Rs. 275 driver. The coil former also seems to be made of paper. No wonder this driver sound good at the mids:thumbsup:.

I had some elaborate plans to drill a small hole in the pole piece to secure the phase plug + tweeter combo. After seeing the well crafted motor, dropped that idea completely. I will use either a paper tube or cork to make the phase plug and then stick it on top of pole piece.

Does anyone know where I can get natural cork pieces/sheet in Bangalore.

Regds...

 

[keith_correa]

I will use either a paper tube or cork to make the phase plug and then stick it on top of pole piece.

Why not use wood?

 

[anilva]

Machined wood may be a better idea than cork. Yes, Many Philips full range speakers have a copper pole plate, mostly in a concave shape.

 

[santhosh]

Does anyone know where I can get natural cork pieces/sheet in Bangalore

Antony, I have a cork piece that I got from IKEA to try under my CDP and Turntable. It is around 12mm thick and around 6 inches diameter. You can have 1/4 of it if you like.

I need some cork sheet too ....to tame resonance in my AV rack caused by usage of a glass shelf (been wanting to fix this for more than a year now). If the vendor does not sell in small quantities, we'll buy together. Did a quick search and found a few addresses. Will call them later today or during the weekend:
cork sheet bangalore - Google Search

Also why have you not used MDF for your speaker build? It is similarly priced as plywood and widely used in speaker making. MDF is supposed to have acoustic properties that plywood does not.

 

[captrajesh]

Why not use wood?

Machined wood may be a better idea than cork.

Wood being far more heavier than Cork, wouldn't using it as a pole piece impede the movement of the cone?

why have you not used MDF for your speaker build? It is similarly priced as plywood and widely used in speaker making. MDF is supposed to have acoustic properties that plywood does not.

Yeah, even I was wondering.

 

[t.antony]

Thanks Santhosh for the offer, I will require a cylindrical piece about 1.5 inch dia and 5inch long, might not be possible to fabricate from the piece you have. Will PM you regarding the cork sheet.

Anil, Keith
I am not sure if the copper pole tip in the speaker is a plating or it's a glued piece, so being a bit over cautious. Since the tweeter will be fixed at the top of the phase plug, thought of reducing the overall weight by using cork. More ideas are welcome.

Captain,
The phase plug is not fixed to the cone - It will be fixed in the pole piece of the motor after cutting away the dust cap. It offers no hindrance on the cone movement. You will get a good idea from this link.
RS-1354 dust cap-ectomy

Santhosh, Captain
I am not planning to brace the interiors of the enclosure in an effort to keep the signal path simple and aid in uniform density fiber stuffing inside the enclosure. MDF is deader than plywood but in practice it also give some resonance artifacts. From my previous experience with MDF(I had used Duratuff and Nuwud brands) and plywood - I found the coloration of plywood more acceptable than MDF. It's purely a personal preference, if I had plans for using extensive bracing for deadening the enclosure I will probably go with MDF as it will be more effective in that case.

I have been reading about people reporting success with sandwiching plywood with MDF, I am toying with this idea of using a 6mm MDF overlay as it will cover up the untidy construction as well (bang on the frugal budget). The carpenter actually mistook my instructions on how to apply screws - I wanted them to be taken out after the glue is set, he thought I might want to open the enclosure for fixing the drivers - so he left the bottom plate removable and fixed all the other sides with countersunk screws . Pulling them out will be a tough job for him.

Also I am planning to magnet mount the drivers to further reduce the cabinet vibrations. It will be a bit tricky to get done, but it really does a good job in isolating the basket vibrations which is a main culprit in cabinet vibration.

Regds...

 

[goldyrathore]

Pretty impressive.
Eagerly awaiting the first impressions.

 

[goldyrathore]

BTW, I did not understand the phase plug + tweeter combo.
Do you need a tapered plug found in such fullrangers, or do you only need a way to mount the tweeter co-axially?

 

[t.antony]

BTW, I did not understand the phase plug + tweeter combo.
Do you need a tapered plug found in such fullrangers, or do you only need a way to mount the tweeter co-axially?

Idea is to mount the tweeter co-axially atop a cylindrical phase plug.

Regds...

 

[suri]

Also I am planning to magnet mount the drivers

how is this done?

 

[keith_correa]

how is this done?

Coupling the magnets of both the front & rear drivers is my guess.