Goodmans Magnum K Refurb and Modification (part 2)

[SteveTheShadow]

I can back up the Docs previous post. Although I have not doped the cones of my Fostex FF225WK wide range drivers, I have applied blu-tak rings around the edges of each aluminium dust cap, right where the cap fixes to the cone, thereby mass-loading and damping the interface between the cone, dust cap and voice coil former, so the effect is similar to the rubber solution around the dust cap cone interface, the Doc advocates. I am looking eventually to do the glue pour mod but am still testing.


Now the accepted wisdom in some quarters is that when you do this you slug the driver, buggering up the speed and all that nonsense. Well I can categorically state that this is simply not true. The damping has successfully tamed a nasty (my how the flat-earthers would love this) peak, right in the most sensitive area of hearing (3-4KHz). And now everything is not drowned out by that annoying emphasis, detail speed attack and tone have improved significantly and I have been able to run the driver wide open, with just a 3.3uF cap to the tweeter (similar in value to the ones the Doc uses I believe)
I would not worry overmuch about the comments about loss of speed. It is frankly bollocks.
Just go ahead and dope the things.

My speakers are tapered quarter-wave transmission lines, so the internal stuffing does a completely different job to the stuffing in most commercial speakers, therefore is is still in there. However even with these, the "don't overstuff" rule still applies with a vengeance. During the testing phase, after the cabs had been built (Sep 2011) it took a while to get the stuffing just so, so that it kept the bass even without sucking the life out of everything else.
With your speakers, Damping out, steel in and driver doped is the way to go.

[Dr Bunsen Honeydew]

Thanks for that Steve.

You pays yer money (well in this case time and respect) and you takes yer choice. If anyone wishes to go onto a DIY forum to check up on me, or to get some sort of me put down (which you will always get from them) then go ahead just don't waste my time by asking me as well. I cannot and will not try to compete with idiots, I don't have the time or the patience. I have been 40 years at developing Doc Mods and I am giving them freely, all I expect in return is a little respect.

[Ronin]

I'd like to make it clear that there is no intention of disrespect on my behalf with any of the questions I may ask.I have no axe to grind and I don't intentionally go out of my way to offend people.

I don't want to sound to sloppy,but I genuinely appreciate all the help you guys are giving me.

I guess It's my insecurity (lack of confidence) that I feel the need to find reassurance from people I think are better qualified than myself.

I would not worry overmuch about the comments about loss of speed. It is frankly bollocks.
Just go ahead and dope the things.

This is the confidence I'm hoping to gain from being on this DIY part of the forum.

I'm not going to do any more searching around the web,I'm just going to "go ahead and dope the things" so then "I" can decide what difference it makes.

My Capacitors are back.

Should I shorten the legs of the capacitors,and are they directional .





Cheers

Ronin

[istari_knight]

You can shorten them if you need to but I wouldn't worry about it. As they are Bipolar (AKA non-polar) they can be mounted either way 'round, if you're OCD its nice to ensure the writing goes in the same direction on every one once installed for uniformity.

[Dr Bunsen Honeydew]

"I guess It's my insecurity (lack of confidence) that I feel the need to find reassurance from people I think are better qualified than myself."

So you think they have bigger or better ears than you, 'cos that is the only qualification that counts.

[Ronin]

You can shorten them if you need to but I wouldn't worry about it. As they are Bipolar (AKA non-polar) they can be mounted either way 'round, if you're OCD its nice to ensure the writing goes in the same direction on every one once installed for uniformity.

Thanks istari, does the "non-polar" mean there is no "+" or "-" terminals or markings as such on the capacitor, so there no fear in me hooking it up backwards !. Fortunately I don't have OCD,well,not when it comes to Hi-Fi anyhow.

So you think they have bigger or better ears than you, 'cos that is the only qualification that counts.

Yeah,I can understand the logic in that Doc,I'll get there in the end.

I'll solder the capacitors in and take a pic for you guys to check-it over.

Question! do I use the same wire from the drivers to the capacitors and then from the capacitor to the socket on the back of the speakers.

Cheers

Ronin

[Dr Bunsen Honeydew]

yes

[Ronin]

Thanks Doc.

I've had a reply from Bostik regarding the Chemical Composition of Evo-stik Impact Contact Adhesive,here it is : Polychloroprene rubber/synthetic resin blend

Is this OK to use on the driver doc,or should I stick to Bison kit.

Ronin

[Dr Bunsen Honeydew]

As I have said many times before you have to use an adhesive that stays flexible, compliant. I know nothing about other glues, I use Bison Kit.

[Ronin]

Fair enough Doc.The only reason I asked,because I had a spare tub left over.But since I've got no definitive answer from Bostik and you're not sure,I've had to a order some Bison Kit (which isn't that easy to get hold of in large quantity),I've just ordered a few tubes.

Soldered in the Capacitors .Could you have a check guys to see if everything looks OK please.



Can I just plug and play these as they are,or do I need to do the doping first.

How much doping (with Bison kit ) from the voice coil do I do.

I've got one Bass driver with a foam surround (had it repaired)and one with rubber surround.Will this matter when it comes coating them up with Plastidip.

Thanks

Ronin



PS,forgot to mention, the Capacitors are glued to the cabinets.