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how old is my K200? [message #1506] Tue, 14 May 2002 10:10 Anonymous I would like to know how old my K200 is. The decal on the back of the head reads: Kustom, Chanute, Kansas, Model Number: J895RV, Serial Number: 5824. the front of the head says: Kustom by Ross Inc. The cabinet is a 2x15 with the ports covered by grill cloth. The cabinet logo plate says: Kustom by Ross Inc. Unfortunately the speakers have been changed to EV's. They are 8ohm's each. They were wired in series but I changed them to paralell for a 4 ohm total. Is this the correct impedance? can someone help? Report message to a moderator

Re: how old is my K200? [message #1507 is a reply to message #1506] Wed, 15 May 2002 07:48 Anonymous The amps with covered ports are 1966 or1967 units.Maybe some one on the site can pin it down with the serial #. 4 ohms is ok, but do not go below that with another cab on the amp with out going to serise wiring. the cabs with 3 15" where 2.7 ohms and that was pushing it!Any time you half the impedence of the speaker load its like doubling the amps output wattage! Report message to a moderator

Re: how old is my K200? [message #1509 is a reply to message #1507] Wed, 15 May 2002 08:12 Anonymous Steve, Thanks I hope someone can give me an exact date. I think you're right . I thought that when the speakers are wired in series it adds the resistance and when they're wired in paralell you divide the value into 1 and add it and divide that into 1. Eg. 2-8ohm speakers Paralell: 1/8ohm=.125+1/8ohm=.125 =1/.250ohm=4ohm. Series: 8ohm+8ohm=16ohm. It's my understanding that it takes more power to drive series wired speakers because of the higher resistance. Am I wrong? I'm so confused! Report message to a moderator

Re: how old is my K200? [message #1510 is a reply to message #1509] Wed, 15 May 2002 10:10 C4ster Messages: 686 Registered: June 2001 Location: Mukwonago, WI (Milwaukee... Senior Member No. When the impedance (resistance) is raised, the current goes down and the resulting power is less. Current = voltage divided by the impedance I=E/R. Then the power = voltage times the current P=ExI. If your ouput voltage is a constant 20 volts, then a 16 ohm load would result in an output of 25 watts. An 8 ohm load would be 50 watts, a 4 ohm load would yield 100 watts and a 2 ohm load would be 200 watts. The only problem with this scenario is that not all amps can handle loads less than 4 ohms. Kustom 200 amps can only handle 4 ohms and anything under that they get squirrely. Also, if the output transistors are not large enough, the transistors can be fried and other components can de damaged. Also, the audio difference between 50 watts and 100 watts is barely noticable. Doubling the power has the effect of raising the sound output about 3dB. 3dB is a noticable change in volume not a doubling of the sound level. I hope this helps. Conrad Report message to a moderator

Re: how old is my K200? [message #1512 is a reply to message #1510] Wed, 15 May 2002 21:52 Anonymous So, you're saying that series wiring takes less power than paralell? Would the amp be louder? Is the K200 a 100watt amp? I always thought it was. Report message to a moderator

Re: how old is my K200? [message #1513 is a reply to message #1512] Thu, 16 May 2002 09:00 C4ster Messages: 686 Registered: June 2001 Location: Mukwonago, WI (Milwaukee... Senior Member Actually, the higher impedance load will PRODUCE less power for the same input. Yes, the K200 is a 100 watt RMS amplifier. RMS is the best rating to use. It actually means how much power (Sound, heat, etc) the amplifier will deliver to a load. Kustom's were rated at 100 watts into 4 ohms. If you attached an 8 ohm load to the amp, the output would less than 100 watts. But because of the internal resistances of the amp itself, the output would not be 50 watts at 8 ohms, the output would actually be a little more. There are a lot of factors that affect the output of an amplifier, the greatest is the load the amp is driving into. The result is similar to adding light bulbs to an electrical circuit. The more lights you add, the more current you draw and the more power you use. There is a limit to the number of lights you can add and there is a limit to an amplifier. It is usually rated in impedance. The limit may be 8 ohms,4 ohms or 2 ohms. It's not exect, but you get the idea. A small K100 is only rated at 8 ohms Conrad Report message to a moderator

Re: how old is my K200? [message #1514 is a reply to message #1513] Thu, 16 May 2002 10:22 ET Messages: 146 Registered: October 2000 Location: Charlotte NC Senior Member this one is fun...my head hurts..but its fun...just for grins..wanted you impy gurus to analyze the picture in last months acoustic guitar rag that shows the basist for Credence CCR playing his 400 kustom head into 4 of the big Sunn 2x15 colesium cabs..now the back of the 400 has a pair of speaker jacks on each side which on that rig is a sperate amp even though it runs off the same single power tranny..a rather large beast similar to those seen at on the side of the road at a small power substation serving 500,000 homes!! all the same Don was explaining to me that, I think, with each of those cabs at 8 ohms you'd be running a 4 ohm load per side to get the max 100watts per side out of that amp for the technical 200 wattrms rating thus the 400 on the front panel? Report message to a moderator

Re: how old is my K200? [message #1515 is a reply to message #1514] Thu, 16 May 2002 12:32 Anonymous OK I think I have it now. I should wire my cabinet in paralell because it will match the output of the amp. 4ohms vs. 16ohms. How can I tell the output? By the way I took the head apart and found pot codes that were from 1966 so I think that's when it was made. Thanks for all the help everyone! Report message to a moderator

Re: how old is my K200? [message #1516 is a reply to message #1506] Thu, 16 May 2002 13:09 ET Messages: 146 Registered: October 2000 Location: Charlotte NC Senior Member I also want to note an agreement on the perceived volume into a single cab at the wattage rating.. I firmly believe there are other factors that contribute to perceived volume...for example.. I have a PV CS400 power amp rated well above the rms output of my kustom 400 but I get as much volume and a tighter bass from my kustom, in fact I have to go to the CS800 model to match the bass punch..now I do recognize the difference a Crown CE1000 can make driving some cast frame speakers...more clarity and punch for sure...but in that 100 to 400 watt range I"m not sure I can beat my old solid state babies..I"d be interested to hear from ya'll on what makes up the rest of the story on percieved volumne and punch... I do know larger value filter caps on the kustoms help with headroom btw....enjoying the thread..thanks ya'll...ET Report message to a moderator

Re: how old is my K200? [message #1517 is a reply to message #1516] Thu, 16 May 2002 16:54 Anonymous To answer your first question. The J895RV would be a 1967 or older map. The J=Jensen speaker cabinet and the RV= Reverb/Vibrato the 895 was the retail price at the time with the cabinet. These amps were the Wide panel. Now to the impedance issue. A amplifier works best at the impedance stated. The older amps didn't state much. The wide panels, K200's and so on ran 100 watts RMS on a 4 ohm load. Speakers are speakers, the impedance is used to wire a cabinet correctly to a amp. 8 ohm amp with two 16 ohm speakers wired in parallel will be 8 ohms. Two 4ohm speakers wired in series will be 8 ohms to the same 8 ohm amp. Volume, headroom, will be the same. This is why speaker companys offer different impedances. Keep in mind, the end result of what you want to drive for cabinets. You can't rob Peter to pay Paul. Running an amp incorrectly is costly. IF you need more sound, add another cabinet with another power amp to drive the second cabinet. To double the volume, you will need 10 times as much power. Tricking the amp by lowering the impedance, will in effect double the power output, but the amp is running twice as hot, and lowering the ava. headroom. The wide panels and K200s can handle two 8 cabinets, that would bring the total impedance to 4 ohms. So be sure all speakers in the cabinet(s) are the right impedance for the wiring arrangement, and wired in phase. JBL'S move inward with a positive voltage applied, most all other brands move outwards when voltage is applied. Mixing brands, in the same cabinet, or having two cabinets side by side with different phased speakers will really take the bottom end and punch out of your sound. A simple flashlight battery is a good source for testing cone movement. Don Report message to a moderator

Re: how old is my K200? [message #1519 is a reply to message #1517] Thu, 16 May 2002 18:44 Anonymous Wow, that's everything I wanted to know. The interpretation of the model number is so simple but it flew right by me. Again, I'll wire it paralell with my 8 ohm speakers for a 4 ohm load to the 100w amp. I certainly don't want to damage my amp because of a stupid wiring error. Thanks. Report message to a moderator

Re: how old is my K200? [message #1520 is a reply to message #1517] Thu, 16 May 2002 18:45 Anonymous Wow, that's everything I wanted to know. The interpretation of the model number is so simple but it flew right by me. Again, I'll wire it paralell with my 8 ohm speakers for a 4 ohm load to the 100w amp. I certainly don't want to damage my amp because of a stupid wiring error. Thanks. Report message to a moderator

Re: how old is my K200? [message #1521 is a reply to message #1517] Thu, 16 May 2002 18:45 Anonymous Wow, that's everything I wanted to know. The interpretation of the model number is so simple but it flew right by me. Again, I'll wire it paralell with my 8 ohm speakers for a 4 ohm load to the 100w amp. I certainly don't want to damage my amp because of a stupid wiring error. Thanks. Report message to a moderator

Re: how old is my K200? [message #1524 is a reply to message #1510] Sat, 18 May 2002 11:53 Anonymous For what it's worth, another way to calculate output power from the output voltage is to square it and divide it by the impedance: 20 * 20 = 400 400 / 4 = 100 watts. Report message to a moderator

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