| K200 B5 PA head help [message #25969] |
Wed, 01 March 2017 16:10  |
Drjones1106
Messages: 19
Registered: March 2017
Location: Seattle
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Junior Member |
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Hello all, I'm new to this great place and have some questions about a Kustom K200 B5 pa head that I lucked into.
The First question is about output. It isn't stated on the back of the amp, and the speakers were not included. From what I found here they should be 4ohms, but I saw something about 8ohm in parallel? There are two output jacks, but the schematic just show them as tip to tip. Would someone clarify for me please? I have a 8ohm bass cab or a 412 stereo @ 8ohm/channel or 16ohm mono. Can I just run both jacks to the stereo cab inputs? Should I pick up a new cab?
The second question gets into the nitty gritty. The reverb is not functioning at all and channel 2 is dead. On the reveb side I've looked over the tank thoroughly, no broken wires, continuity tests show nothing open. So I moved to transistors on the board. one is completely dead. I also tested the trannies on the channel two board, finding one faulty reading. So replacement time! Both broken transistors are the pet8002 or se4002. I saw here about replacement with 2n3904 or 3906 or possibly 5088/89? I have plenty of both as well as many other types, so give me a recommendation, what works/sounds best in your opinion?
Question the third. I intend to use this as a guitar or bass amp. Ideally I'd like to mod one channel to be more suited to bass. I've seen some comments about switching input caps, but no values mentioned. Should I just be working harder and using a R-C calculator? anything worked well for you?
Q4: I've also seen on here comments about not overloading the preamps with a high gain signal, like overdrives/fuzzes/etc. I build effects and was hoping to use this amp as a clean amp specifically for pedals. Is that a bad idea? Its sounded great when I tried it out with some stomp boxes.
Q5: I also would like a master volume. It couldn't be as easy as wiring a pot to the output wire with lug 1 to ground, right? That'd be crazy.
I'll also be replacing the two prong cable for a grounded one, but that's old hat.
Thanks for any help. I'm really glad to have found this forum. It's already been an invaluable help to me.
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| Re: K200 B5 PA head help [message #25972 is a reply to message #25969] |
Wed, 01 March 2017 18:25  |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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Welcome to the place.
The amp will work best with a 4 ohm load. Because the two output jacks are wired in parallel (tip to tip), if you plug in an 8 ohm load to each of the two jacks the amp will see a 4 ohm load. So, your 4X12 cab would work best with each 8 ohm pair connected to each of the jacks.
As for the replacement transistors, you need to use the correct type as a replacement. The SE4002 is an NPN silicon transistor, so a 2N3904 would work, not a 2N3906. Just be sure to install the replacements with the pins in the correct positions and they should work just fine.
As for adding a Master volume, you might be able to add one at the input to the power amp. I've never tried it, but I would guess that it could work.
As for using the amp with FX, you shouldn't have any problems. The input circuits are really no different than any other amp. Lots of guys here use them with pedals all of the time.
Again welcome to the place.
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| Re: K200 B5 PA head help [message #25975 is a reply to message #25969] |
Thu, 02 March 2017 06:12 |
stevem
Messages: 4774
Registered: June 2004
Location: NY
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Senior Member |
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Hello and welcome!
You might try out auditioning different brand Transistors as they do sound very slightly different from one another just like IC chips do.
I can't see a need for a master volume in this type of SS amp as they sound like crap when you push the preamp too hard, and as you have seen popping the first gain stage transistor is easy at times!
If you just gotta have a master volume on one of the channels I would go with a 25K pot.
If anything these amps are known for there nice crunch when up loud enough and playing guitar which comes from pushing the output stage.
The amp will output 100 watts of clean power so if you fo not want / need it thst loud it will output a little more than half that wattage into a 8 ohm load.
[Updated on: Thu, 02 March 2017 06:17] Report message to a moderator |
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