Guest Posted September 15, 2002 Report Share Posted September 15, 2002 Hi,I'm wondering if someone could explain to me some of thedetails of bypassing pots. In particular, I'm wonderingif people actually disconnect the leads from the pot andthen connect/short them together, or whether they leavethe wires on the pot and short "in place".Thanks, Link to comment Share on other sites More sharing options...
kkantor Posted September 16, 2002 Report Share Posted September 16, 2002 Disconnect the pot, and connect the appropriate wires directly together. Be sure you understand which wire belongs where, and that varies from model to model. -k Link to comment Share on other sites More sharing options...
Guest Posted September 16, 2002 Report Share Posted September 16, 2002 Thanks for the reply.I ended up doing what you suggested mostly out of lazyness -it was a lot easier to simply remove and connect the wiresthan soldering in a new connection between the two terminals,since there were already wires connected. (I used the circuitdiagram available here to figure out which wire was what -thanks to whoever made that available.)I am wondering how much of a difference there would be betweenthe two methods, however. It would seem that if one shorted thetwo terminals in place then some current would still flow throughthe pot - I guess this would just be wasting the current capacityof the amp? Is that why removing the pot from the circuit altogetheris suggested?Also, how much of a sonic difference does the direct bypassmake? (Compared to the original setup with pots centered.)My mid/tweets weren't functioning before the bypass so Idon't have a reference for comparison.Thanks, Link to comment Share on other sites More sharing options...
tysontom Posted September 17, 2002 Report Share Posted September 17, 2002 >>Also, how much of a sonic difference does the direct bypass >make? (Compared to the original setup with pots centered.) >My mid/tweets weren't functioning before the bypass so I >don't have a reference for comparison. >>Thanks, Disconnecting the level controls ("pots") on AR speakers (you did not mention which model) is certainly one way of ensuring reliability. There would be no level controls to oxidize, no "dropouts" or other related problems. However, the speaker won't sound exactly right or natural. Using the AR-3a as an example, the sensitivity of each driver (woofer, midrange and tweeter) is not identical, so the level controls can help to get more uniform output across the frequency spectrum. The midrange driver in that speaker has greater sensitivity than the tweeter, and by putting the mid-range control on the "dot" and putting the tweeter at close to full output better balances the output of the speaker. Bypassing both controls will also give the AR-3a a somewhat unnatural "presence" or mid-range brightness to the sound, unless the listening room is inordinately "dead."A better -- though admittedly more difficult -- solution would be to completely rebuild the existing level controls or put new ones in their place. --Tom Tyson Link to comment Share on other sites More sharing options...
kkantor Posted September 17, 2002 Report Share Posted September 17, 2002 Not all crossovers use the pots in exactly the same way. Sometimes, they form part of the circuit no matter how they are set, and it is best to leave them in circuit. Often they are simply "series elements" that work best when removed fully. I guess I should have been more careful with my answer. Happy to help further if you can mention the product, or can trace the exact crossover design.Ken KantorIntelligent Audio Systems, Inc. Link to comment Share on other sites More sharing options...
Guest Posted September 18, 2002 Report Share Posted September 18, 2002 Thanks to both replies. I suppose I should have described mysituation more fully before.I have a pair of 2ax's, whose pots were definiately at theend of the lives.Based on information on this forum/site (and help from a friendwith a steadier hand than mine), I managed to remove the grill,and discovered that the surrounds on the bass driver were alsoon their last legs.Although I'm not sure this was the ideal kit for the driver,I obtained the generic 10" surround replacement kit fromparts express and managed to replace the surrounds. I didn'treplace the dustcap, however - nor did I remove and replace theoriginal. I don't know how severe the danger of misaligning thecone is in practice. I had other minor difficulties followingthe instructions due to the wire mesh on the drivers protectingthe cone - this prevented me from manipulating and shimming thecone independently from the support frame, so I ended up gluingthe surround to both the cone and the frame simultaneously, usinga light magazine to weight the surround down while the glue set.I then checked the mid/tweets by manually shorting the pots,and they appeared to be okay. I briefly attempted to solder ashorting wire onto the pot terminals, but given the wire andsolder already on the terminals, and the confines of the cabinetwith the other wires in place, I found that this was beyond myskills. So I ended up heating the terminals till the old solderliquified and simply yanked out the wires. I then twisted andtaped together the relevant wires, repackaged everything, andcalled it a day.I am not particularly keen on reopening the cabinet in the nearfuture, but I would appreciate any feedback/comments you may haveto offer. Also, there are a few questions that I still have.First, is the putty/driver seal reusable? I had gotten some fromparts express when I ordered the surround kit, and so I used thenew ones, but it wasn't clear to me in the end whether that wasreally necessary (the old putty still seemed fairly pliable).I also put a lot less putty on that was originally there - itseemed as though the amount that was originally there was overkill.Second, I noticed that parts express sells stuffing material thatisn't the fiberglass material which is what I believe is in my2ax's. I wasn't very careful about handling the fiberglass - Iwas thinking that getting the non-toxic material may be usefulin the future. Are the materials essentially equivalent?I apologize for the length that this message has grown to,and if I've made any terminological errors - I didn't knowanything about speaker internals/repair 2 weeks or so ago.Thanks for the forum! Link to comment Share on other sites More sharing options...
kkantor Posted September 20, 2002 Report Share Posted September 20, 2002 I'm travelling, so forgive the brief reply. I can answer in greater detail later, if you want. Not a problem.1- What you should do with the existing pots in the 2ax's depends on their mode of failure: open wiper, open element, or various types of shorts. If you, or your friend, knows how to test them with an ohmmeter, you can make a decision. Replacement is possible, as is substituting a fixed power resistor. If you leave things as is, Tom T. gave a pretty good description of what you will hear. And there is no substitute for listening and judging. 2- As long as a decent air seal is preserved, don't worry about the putty. I use thin, adhesive foam weatherstripping, myself. 3- Replacing the fiberglass is not recommended unless you have means to test what you do. There are good replacement materials out there, but they don't swap at a 1:1 ratio, and so require some experimentation to get right. You can always get new fiberglass water heater insulation, if you need some in better shape than what you have. Put rubber kitchen gloves on when you handle it, and all should be fine. Other than a little itchiness if you rub against it, the main health issues with fiberglass involved workers who were making hundreds of speakers every day for years. And that would drive most people crazy first. -k Link to comment Share on other sites More sharing options...
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