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Looked inside K200B2 [message #10269] Mon, 12 January 2009 22:43 Go to next message
WVTom is currently offline  WVTom
Messages: 16
Registered: January 2009
Location: West Virginia
Junior Member
First I want to thank Stevem for the welcome to the community. I appreciate the information provided right from the start. I'll try to be brief here and seek information from you guys and gals.

I removed the amp from the housing and discovered the following: It was full of dirt, cobwebs, dead spiders and other bugs. But I found that someone has been inside at some time in the past. Each of the input jacks designated LOW for the Bright and Normal Channels have toothpicks inserted between the metal clips keeping the innermost part from touching the outermost. I am in the dark as to why someone would do this. Maybe you guys can shed some insight on this for me. As for the rest of the interior, I cannot see any other modifications.

In addition to this, Stevem I have attempted to locate the same 4500mfd@50 volt rail filters on the net. I am having no such luck, so can you direct me to the appropriate web site. I am going to only use the amp for guitar and have no intentions of any other instruments running through it. Are there other things I should be looking at before replacing the above?

Also, I should note that I am not an electronic whiz, (just basics) but there is a electronics technician at work who I will call upon for the nitty gritty repairs. Would he need the schematics for this amp? If so, is there somewhere I could obtain these?

Thanks in advance for any and all assistance.

Tom
Kustom K200B-2 w/ 3 12's
Fender Vibro Champ (72) Given to my son
1970-72 Gibson SG w/ Bigsby per Ser. # Also given to my son
2005 Taylor T5 - C2 (Koa)
Alvarez AJ60
2010 Taylor 814ce Tobacco Burst

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Re: Looked inside K200B2 [message #10270 is a reply to message #10269] Tue, 13 January 2009 06:47 Go to previous messageGo to next message
stevem is currently offline  stevem
Messages: 4733
Registered: June 2004
Location: NY
Senior Member
Why they did what they did to those input jacks I do not know.
those tooth picks are holding open the shorting switch that each jack has, the function of the switch is to short the preamp when that jack/channel is not in use. Having those switches open like that will make the amp pick up hum if the controls on that channel are up, like wise you will get some level of additional hiss also.
The only thing I can guess is that someone tryed to re-bend the hook portion of the switch( the part that grabs the tip of a 1/4" plug) as with age and use these can loose there grip.
The problem is when you do that the wrong way you end up with the swicth not opening to let signal pass when a cord is plugged into the jack.
Your hum and noise problem may be all due to that.
If you unbolt the jacks from the front of the amp you can use a needle nose plyer to reshape these two metal items, but it takes some fooling with since both the switch tang and the hook have to be bent at the same time in most cases, than you re- bend the hook to grip a cord tip well.
On Wedensday I will post you a supplyer and part number for the filters if someone does not cover you here over night.

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Re: Looked inside K200B2 [message #10287 is a reply to message #10269] Fri, 16 January 2009 15:06 Go to previous messageGo to next message
WVTom is currently offline  WVTom
Messages: 16
Registered: January 2009
Location: West Virginia
Junior Member
Thanks Stevem for replying to my messages.

I have not been able to do anything with the amp yet due to High School Basketball games this week. One more tonight and then I am free till Monday night except for Church.

I am going to look at working on the jacks a little now before having to leave for the game. If you find some free time down the road, can you go ahead and give me the information on the 4500mfd 50 volt rail filters as to where to locate the original or the equivalent replacement ones.

Thanks and all have a good day and weekend.

Tom
Kustom K200B-2 w/ 3 12's
Fender Vibro Champ (72) Given to my son
1970-72 Gibson SG w/ Bigsby per Ser. # Also given to my son
2005 Taylor T5 - C2 (Koa)
Alvarez AJ60
2010 Taylor 814ce Tobacco Burst

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Re: Looked inside K200B2 [message #10292 is a reply to message #10269] Mon, 19 January 2009 06:25 Go to previous messageGo to next message
stevem is currently offline  stevem
Messages: 4733
Registered: June 2004
Location: NY
Senior Member
After a search in the my mouser electronics catalog I found that the two major players who make these large can type filter no longer make the stock kustom value in the dead on size can, but since we want to goo up in mfd value anyway heres what I found.
Mouser part number
539-CGS50V6500
is a Mallory brand 6500 mfd @50 volt can cap, its diameter is 2" by 3.125" tall.
This diameter is 1/2" less than the stock size of 2.5" so you have two choises,1) you can electrical tape down strips of card board to the bottom of the can to get a 1/4" layer witch will give you back the lost 1/2"
2) you can build up a layer of silicone glue(will have to set up for two days) to get the 1/4" or so difference built up.
3) you can silicone them to the floor of the amp.
4) you can buy the right size new can clamps( mouser #539-vr8a) and drill new mounting holes in the floor of the amp to bolt them down to.
If it where me I would do choise 1 or 2, in any case if you use a clamp do not crush the bottom of the can with the clamp.
You can find the mouser site on the web, they are open for phone orders untill 7pm CST.
These filters are 20 dollars and change each.

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Re: Looked inside K200B2 [message #10299 is a reply to message #10292] Mon, 19 January 2009 15:19 Go to previous messageGo to next message
WVTom is currently offline  WVTom
Messages: 16
Registered: January 2009
Location: West Virginia
Junior Member
Steve

Thanks for the information on the part #. I have placed the order and now am just waiting for arrival around the end of the week. I'll let you know how things go.

I really appreciate the assistance you have given thus far. It is nice to know there is someone willing to take time out of their busy schedule and offer assistance to a total stranger.

Thanks again...

Tom
Kustom K200B-2 w/ 3 12's
Fender Vibro Champ (72) Given to my son
1970-72 Gibson SG w/ Bigsby per Ser. # Also given to my son
2005 Taylor T5 - C2 (Koa)
Alvarez AJ60
2010 Taylor 814ce Tobacco Burst

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Re: Looked inside K200B2 [message #10561 is a reply to message #10269] Sun, 01 March 2009 16:59 Go to previous messageGo to next message
WVTom is currently offline  WVTom
Messages: 16
Registered: January 2009
Location: West Virginia
Junior Member
Hey Steve,

I just wanted to say after so long since you provided the information to me that I have the amp up and running. I did not put the new filters in until a week and half ago. As I stated earlier, basketball with my daughter. A side note is that they won their Regional Final this week and now have one more test to see if they get into the State Tournaments.

Anyway, the amplifier has no more popping at shut down. Smooth as silk one could say. There is some hissing noise coming from one of my speakers. This happens to be a replacement Jensen in the cabinet that I put in a few years ago. The two other Jensen 12's (originals) only have a small amount of the hiss.

This thing sounds really great. Brings back some old memories and I forgot how loud these things could be. When I play it now, I only turn the volume about 1/4 to 3/8's of an inch and my Taylor T5 cranks through it. I've yet to find the time to run my old SG through it which is what I used in the early 70's, but hopefully that will not be far off.

Thanks again.....

Thanks once again for your help.

Tom
Kustom K200B-2 w/ 3 12's
Fender Vibro Champ (72) Given to my son
1970-72 Gibson SG w/ Bigsby per Ser. # Also given to my son
2005 Taylor T5 - C2 (Koa)
Alvarez AJ60
2010 Taylor 814ce Tobacco Burst

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Re: Looked inside K200B2 [message #10564 is a reply to message #10269] Mon, 02 March 2009 08:24 Go to previous messageGo to next message
stevem is currently offline  stevem
Messages: 4733
Registered: June 2004
Location: NY
Senior Member
Glad to hears its up and running well.
the added hiss form your new Jensen driver is most likly due to its added top end frequency range over the stock drivers. Also old cones can tend to soften up with age in humid areas of the country and this will lower there top end some.

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Re: Looked inside K200B2 [message #10581 is a reply to message #10561] Mon, 02 March 2009 17:14 Go to previous messageGo to next message
pleat is currently offline  pleat
Messages: 1452
Registered: June 2004
Location: Belding, Mi
Senior Member
Tom, the hiss you mentioned in the replacement Jensen speaker.
Did you replace it with a 16 ohm speaker? If it is a 8 ohm replacement then you would hear a louder hiss in the replacement speaker since it is half the impedance of the 16 ohm speakers and would actually be louder than either of the other two original speakers.
pleat

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Re: Looked inside K200B2 [message #10584 is a reply to message #10269] Mon, 02 March 2009 23:13 Go to previous messageGo to next message
WVTom is currently offline  WVTom
Messages: 16
Registered: January 2009
Location: West Virginia
Junior Member
Pleat,

I did replace the original Jensen with an 8 ohm Jensen. I had heard or was told by someone at some point in time that these were 8 ohm speakers.

I am looking at the old speaker pulled out of the cabinet at the time of the replacement. It is marked 30410 C8774-4R C12N 220046.
Stamped on the back of the speaker baffling is 42W9902. I did replace the original with a C12N from Jensen.

Of course all of the above is just extra regarding your post about the ohms. Are the original speakers 8 or 16 ohms? If I should have a 16 ohm in the cabinet, I'd rather get one and keep things in the proper order.

Thanks for your post.

Tom
Kustom K200B-2 w/ 3 12's
Fender Vibro Champ (72) Given to my son
1970-72 Gibson SG w/ Bigsby per Ser. # Also given to my son
2005 Taylor T5 - C2 (Koa)
Alvarez AJ60
2010 Taylor 814ce Tobacco Burst

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Re: Looked inside K200B2 [message #10585 is a reply to message #10269] Tue, 03 March 2009 06:26 Go to previous messageGo to next message
stevem is currently offline  stevem
Messages: 4733
Registered: June 2004
Location: NY
Senior Member
these amps are made to handle down to a 4 ohm load. Your three original speakers where 16 ohms each, all wired in parallel for a 5.3 ohm load.
You now have the minimum 4 ohm load which is fine, but just keep in mind that the 8 ohm driver is going to get twice the wattage that the other two drivers are running at which may be a issue if you ever use the amp at louder volumes.

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Re: Looked inside K200B2 [message #10591 is a reply to message #10585] Tue, 03 March 2009 17:04 Go to previous messageGo to next message
WVTom is currently offline  WVTom
Messages: 16
Registered: January 2009
Location: West Virginia
Junior Member
Thanks for the additional information regarding the speaker ohms. I doubt I will ever take the opportunity to crank the amp up, but one never knows.

I believe I'll start looking at various web-sites searching for a 16 ohm Jensen. It would really be nice to find an original replacement, or a replacement model with the chrome center. I have searched many times for one, but never located it yet.

As for the 8 ohm speaker, I have another amp which has a 8 ohm 12 in it (marked on the amp). Before placing the Jensen in the Kustom cabinet, I hooked it up to the other amp and there was a world of difference in the tone quality. I'll just move the 8 ohm to the other amp when I pick up a 16 ohm speaker.

If anyone has suggestions for a good replacement other than the Jensen, let me know.

Thanks again....Tom

Tom
Kustom K200B-2 w/ 3 12's
Fender Vibro Champ (72) Given to my son
1970-72 Gibson SG w/ Bigsby per Ser. # Also given to my son
2005 Taylor T5 - C2 (Koa)
Alvarez AJ60
2010 Taylor 814ce Tobacco Burst

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Re: Looked inside K200B2 [message #10592 is a reply to message #10591] Tue, 03 March 2009 17:15 Go to previous messageGo to next message
LesS is currently offline  LesS
Messages: 477
Registered: December 2002
Senior Member
Hey Tom,
Just an idea- you might find your 8 ohm Jensen less objectionable if you mounted it in the lowest position in your 3x12.

If you like the aluminum dust caps, you can always add them yourself to a speaker.
To put them on you need to use speaker glue.
A great source for the caps is ebay - you can get two 4 inch aluminum JBL caps for $17 shipped.
See ebay or the website: www.myaudioaddiction.com
He also has 3 inch aluminum caps which would look more correct on a Jensen that a 4 inch.

-Les S

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Re: Looked inside K200B2 [message #10598 is a reply to message #10269] Thu, 05 March 2009 08:25 Go to previous messageGo to next message
rodak
Messages: 511
Registered: October 2001
Location: Georgia
Senior Member
Can you just put the aluminum caps over the existing paper dome, or is it better to replace it? If the latter, how do you go about replacing it?

Another good source for the JBL domes is Weber Speakers: www.tedweber.com. Terrific guy to deal with, and extremely knowledgable about all things speakers.

www.combo-organ.com

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Re: Looked inside K200B2 [message #10599 is a reply to message #10598] Thu, 05 March 2009 11:39 Go to previous messageGo to next message
chicagobill
Messages: 2005
Registered: April 2003
Senior Member
I think it depends upon a couple of factors. If the original paper dome is solid and not vented, and the new metal dome doesn't touch it when in position, the metal dome can be glued in over the original.

Most likely though the metal dome will be flatter than the original one, so the paper one will need to be cut out first. It can be removed with a sharp knife. I'd just cut it off right at the glue line, being careful not to cut the cone itself.

If the original dust cap is vented, the new metal cap should also be vented. These are the metal caps that look like they have a black dot in the center of them. This is actually a mesh or screen covered hole.

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Re: Looked inside K200B2 [message #10600 is a reply to message #10269] Thu, 05 March 2009 12:13 Go to previous messageGo to next message
stevem is currently offline  stevem
Messages: 4733
Registered: June 2004
Location: NY
Senior Member
A while back I managed to repair a broken voice coil wire on one of the CTS 10s in my K100-8 that was not working.
When I removed the aluminum voice coil cover I fould that two where stacked togetheir!
I always wondered why that driver has less high end when it was working, and now I know why! LOL!

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Re: Looked inside K200B2 [message #10610 is a reply to message #10600] Fri, 06 March 2009 21:25 Go to previous messageGo to next message
LesS is currently offline  LesS
Messages: 477
Registered: December 2002
Senior Member
Re: "Can you just put the aluminum caps over the existing paper dome, or is it better to replace it? If the latter, how do you go about replacing it?"

Hi Rodak,
The caps are a little bigger than 4 inches, so you can put them right over JBL caps (which are something like 3.94 inches.)
You need to use speaker glue.

I have actually put these on top of paper caps that were about 5 inches. It looks a litle odd when you have the speaker out of the cabinet but behind the grille cloth it looks perfect - you cannot tell it.
-Les S

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Re: Looked inside K200B2 [message #10612 is a reply to message #10269] Sat, 07 March 2009 13:25 Go to previous messageGo to next message
rodak
Messages: 511
Registered: October 2001
Location: Georgia
Senior Member
Thanks for the info. I guess I'd rather replace the existing paper cap, if possible, to avoid affecting the high-freq response (I guess this would be less of an issue for larger speakers, right)?

What sort of precautions should be taken to avoid getting foreign particle in the voice coil gap? I'd be afraid of having bits drop down in there while cutting the paper cap off. i guess I could do it upside down.

I don't have any plans to do this now, just reaearching in case I ever have the need to.

www.combo-organ.com

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Re: Looked inside K200B2 [message #10617 is a reply to message #10269] Mon, 09 March 2009 06:23 Go to previous message
stevem is currently offline  stevem
Messages: 4733
Registered: June 2004
Location: NY
Senior Member
As long as what might fall in the gap is not magnetic you can vacume it it out.
Also if you hav someome hold the speaker on edge while you cut on the lower side of the dome nothing will fall in anyway.

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