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12-08-05
Q: Hi there.
Couldn't help notice your comment to avoid the Kenwood KR-9600 receiver, just curious about your opinion on them. I just aquired 2 of them in near mint condition and they perform flawless. The power rating is 160-WPC into 8 ohms and that's conservative.
Don't take this as a flame, I've heard other comments about them pro's and con's.
Thanks
John MA: Hello John,
I have been waiting for someone to call me on that. The reason is simple,
the KR-9600 uses output ICs which are known to be problematic. At the 160
watt output level they're some of the hardest working ICs in the land, and
are no longer available.
12-02-05
Q: hi i was just wondering what youre opinion is of the vintage marantz receivers-say the 2200 series. i see a lot on ebay and was just wondeing how they stack up to the vintage sansui and onkyo pieces. i thought id read somewhere that the marantz tuners were not too great any input would be appreciated. one more question. i noticed some audio companies that originally had made stuff in japan started making stuff in korea. did this make a big difference in quality? thanx again bruce
A: Hello Bruce,
Stick with the mid-era 2200 receivers (1974-1976) and go for the 2250 and up. I would recommend the 2275. The tuners can compete with Pioneer and Sansui, but they must have a fresh alignment to do so. I have had limited experience with Korean made gear, most of that happened after the 70's.
11-28-05
Q: I just bought my first electric guitar and want to patch it to thestereo . . . don't want a regular guitar amp. My system is incredible and I want to use it for my guitar. Suggestions?
Thanks!
A: Hello James,
Don't do it. Your stereo is not designed to handle the dynamics of an electric guitar. Chances are good that you will blow it up.
11-26-05
Q: I have a lot of old albums. Many are from garage sales. They have a lot of scratches on them. Is there any electronic equipment which I can hookup to my amplifier that would filter-out the noises from these albums?
I have a Marantz stero amp.
Thank you,
Dennis
A: Hello Dennis,
Almost all computer audio recording software that is designed to record CDs includes a "cleanup" function for vinyl. There are some stand alone units from the 70's that you could use with your Marantz, but they don't really work all that well and are somewhat hard to come by.
11-18-05
Q: I recently acquired a near mint Sansui TU-717 tuner and am now "hooked". I have read that its performance can be improved by various modifications. Is it worth the expense and, if so, do you do such work? If not, is there anyone reliable in the Pacific Northwest (I am in Vancouver BC)?
Thanks in advance for your time and reply.
A: Hello John,
The TU-717 is one of my favorite tuners, I use one on my test bench. Yes, I am aware of various modifications that claim to enhance performance. Personally, I do not choose to modify vintage equipment, it's kind of like flaring the fenders on a '55 Chevy. Given the state of commercial radio, I just don't see the point of enhancing garbage.
11-08-05
Q:I acquired some original service manuals from a TV-Stereo shop that was in business in the 70's and 80's. Two of the Pioneer ones, QX-949 and QX-747 say FUW version on the front cover but give no other explanation. Can you tell me what this stands for? The other Pioneer's I have say KCW, KUW, FVZW NBW or FW and the front cover says what they are.
Judy
A: Hello Judy,
I have seen, but do not completely understand, the country codes on Pioneer manuals. The version statement usually indicates for which country the manual is applicable. Usually the only difference between manual versions lies in the power supply and AC power sections as different countries use different voltages and frequencies as well as having different electrical safety standards. There also could be differences in the AM and FM bands. The QX models happen to be 4 channel units, which may or may not be a relative factor. It would take a trained eye on the manual itself to determine for which country it was intended.
11-04-05
Q: I just picked up a pair of ADS L730 floor standing speakers (3 way with 10" woofers). The info plate on the back reads 100 watts nominal, 175 watts maximum, 6 ohms nominal, 4 ohms minimum. Can you explain what all this mean, especially the ohms. I thought speakers were either 8 ohm or 4 ohm etc. Also, what would be the minimum watts per channel, amp or receiver, that you would recommend to use with these type of speakers.
Once again, thanks for your help.
John
A:Hello John,
A speaker's impedance varies with frequency, so they're saying that the lowest impedance the speaker will produce over it's frequency range is 4 ohms. You should use an amp that will handle 4 ohms. "100 watts nominal" is basically a recommendation of the size of the power amp used. "175 watts maximum" means if you put more than that to the speaker you may damage it. I would use an amp rated at a minimum of 50 watts RMS per channel.
11-04-05
Q: What is "damping factor"? I was looking at 2 amps. Pioneer SA-9100, and SA-9500. 9100 says 60 wph. 9500 says 80 wph. So, I'm thinking okay go for the extra 20 watts. However the 9100 says damping factor 70. The 9500 says damping factor 30. So which is better, the extra 20 watts of the 9500 or the higher damping factor of the 9100? I read something that said the higher the damping factor the better control the amp had over the speakers. Would the human ear even tell a difference? Thanks.
Ben
A: Hello Ben,
The damping factor is the ratio of the amplifier's internal impedance to that of the speakers. Generally, the higher the number the better, but, most tube amplifiers have a very low damping factor. Given that tube amps are very well respected for their sonic performance, I'm not sure damping factor is a major concern in regards to audio performance.
11-03-05
Q: Hi There,
I have a Pioneer SX-780 and would like to know if I can connect my Pioneer SA-7100 as a preamp for the SX-780 or is it visa versa.
Sorry for the dumb question.
Bill
A: Hello Bill,
The SX-780 does not have "pre-out/main-in" capabilities so it cannot function as a preamp or separate amplifier. It makes little sense to use the 7100 as a preamp for the 780 since you will eliminate the tuner. You could use the record out on the 780 to feed an AUX input on the 7100, but, what's the point? The 780 is rated at 45 watts per channel and the 7100 at 22 watts per channel.
10-13-05
Q: Having just received an Rt-701 Pioneer from ebay, it appears (without tape installed) that the motor turns just as fast in play mode as it does in reverse or fast forward mode. Is this normal? I am looking for tape locally to test. I have gleaned some info off the net suggesting capacitor failure or IC motor controllers that could cause this. It just seeps that even without tape the paly mode should spin much slower than the reverse mode.
Un-educted in Wyoming
A: Hello Nate,
With no tape loaded the take-up reel will accelerate to high speed, and so will the supply reel in the opposite direction. The difference is in the torque developed by the motor in various modes of operation. Load a tape and call me in the morning.
10-02-05
Q: Just purchased a Pioneer SX 950 on EBay. Sold as sounds great. However there is a lot of destortion and noise on all FM stations even 3+ signal FM Stations. This noise doesn't occur using cd's. I am using a simple wire antenna that works great on my SX 737. I am in a large city, signal has never been an issue. Does this sound like a repair or possibly an antenna problem with the beefier receiver?
ThanksMiles
A: Hello Miles,
Sounds like the FM section is in need of alignment, or perhaps repair.
09-09-05
Q: I am going to be using both Marantz 2230B and 2238 Receivers in the near future - I have inherited them from a German relative. I want to be able to use them as soon as they arrive so given that the UK is 240V and Germany is 110V what should the rating of the fuses be in the back of the units? What type of fuses should they be?
Thanks
Charlie
A: Hello Charlie,
If the units are capable of 240/110 operation, the fuse required for each voltage will be stated on the back of the unit.
09-08-05
Q: Hello,
I own a Pioneer SX-980. Basically, I am writing to see if you have any advice on how to remove the face plate (if it's even possible) so I can get to the buttons and switches in there with my contact cleaner.
Cheers,
MaxA: Hello Max,
First remove the top and bottom covers. Then remove all of the knobs and switch covers. Some of the knobs may have set screws that will require a small allen-head driver. Next, there will be a few nuts holding the faceplate located at the base of the controls. Finally, there will be a few screws to remove from the top and/or bottom of the faceplate.
09-01-05
Q: I'm using a Yamaha CA1010 and a Hafler DH500 (in different systems). I have a question regarding solid state gear and leaving it powered on all the time. I have been told that it is not constant heat that ages equipment but rather the repeated cycle of heating and cooling. This seems to make sense on an intuitive level, but does it have any validity? Is the opposite true?, i.e. that leaving equipment on all the time will cause more problems as it ages.
Over the years I've noticed that the Hafler's fan stays in med. to high gear all the time, even when first turned on and left to idle. Any suggestions?
Thank you in advance, Paul KostaA: Hello Paul,
A subject of much controversy, that. Leaving equipment on all the time wastes electricity, contributes to global warming and costs money. True, the initial turn on electrical surge is the hardest thing any piece of equipment is likely to do all day, but it's designed to handle that. That's why there is a power switch. In the professional world when a piece of equipment is meant to be kept powered all the time the is no power switch. Things generally fail during or after performing work. When your stereo is on, electrons flow and work is performed whether or not it's producing any sound. In theory, the less work over time, the longer the life. It's up to you. I don't know of any long term experiments with identical units, one being switched on and off and one being left on, to establish which method is the best. Personally, I have my way with all of my electronics and turn them on when I need them and off when I don't.
08-15-04
Q: When running two pairs of speakers with my Marantz 2230 receiver in the mode where both main and remote speakers are played at the same time, will it damage my receiver if one set of speakers is 8 ohm and the other pair is 4 ohm nominal impedance?
I have searched the owner's manual and the service manual but can't see where this issue is addressed.
If it is a try and see proposition, would the receiver be likely to give me some warning by feeling too hot, or would it just blow the receiver up at once?
In case the answer is that it would damage the receiver, here's a followup question. When using the 2230 as a preamp, can the preamp out signal be split with a Y-cable successfully and sent to two separate power amps?
Thanks,
Ed
A: Hello Ed,
Running a pair of 8 ohm speakers in parallel with a pair of 4 ohm speakers will produce a load to the amplifier of less than 4 ohms. The 2230 will not drive a load of less than 4 ohms, at least not for very long. In answer to your second question, yes.
08-11-05
Q: have a marantz 2235b, looking for the pre out to main in plugs (2), do you have them? if not any suggestions? i understand they increase the power through the receiver, true? thank you, b.
A: Hello,
Those jumpers are not required on this model. They do nothing to enhance the performance of the receiver. If you must, you can use ordinary RCA cables.
07-18-05
Q: I have a TEAC A-3440 multitrack reel-to-reel tape deck that I used to record original music, but haven't touched in a few years. When I recently tried it - it rewinds & fast-forwards fine - but won't play or record... It tries, but the (pinch roller or captstan?) won't engage. I'd read online once that there's a problem like this that is known to happen frequently w/ this deck, but can't find this info anywhere anmymore. Any help, suggestions would be greatly appreciated - as I now have no way of retrieving or re-mixing anything!
Many thanks in advance,
TimA: Hello Tim,
Yes, this is a common problem. The solution is to do a fairly major teardown of the transport. The pinch roller actuating mechanism must be removed, cleaned, re-lubed and reinstalled.
06-19-05
Q: I own a 1970’s ESS 200W stereo amplifier, with a separate pre-amp. This is a great power amp for my ESS AMT speakers. Everything worked fine until a few days ago, when one of the channels started to distort horribly. The other channel still has clear output. I decided to open up the unit after the pre-amp tested fine, using a different power amp. Inside the amp I found that a couple of capacitors where replaced sometime in the past (I am the second owner), but everything else was left original. I replaced the two capacitors with 100mfd @ 25V, same as the originals, thinking this may be the problem. With the new capacitors there is still the same distorted output. Having the amp open, I decided to bypass the two newly installed capacitors, connecting a piece of wire between the cap’s polarities. Big surprise: the sound came out as clear as light, same like the other channel. But now the downside: After ten-fifteen minutes, one of the finals on the amplifier started to warm-up. I disconnected the amp immediately. What is wrong with it? And how was it possible that the sound was clear with the capacitors bypassed? Please advice what to do. I tried looking up schematics with no luck.
Thank you,
Emil
A: Hello Emil,
I am not familiar enough with this amp to fathom a guess as to what you did when you bypassed the capacitors. I strongly recommend against doing anything like that again. Distorted output can be caused by many things, you are going to have to get the schematic or turn the amp over to a professional. Either way it's better than burning down your house. ESS is still in business, last I checked, try contacting them.
06-04-05
Q: You answered a person interested in buying vintage Pioneer and Sansui receivers as follows: "Look for any Pioneer receiver from the mid 70's, such as the SX-838, or from the late 70's such as the SX-1050. Avoid the later, lower power receivers." Can you be a little more specific on what you meant by " later, lower power receivers" and why you make that recommendation?
Thank You,
JohnA: Hello John,
Sure. In the late 70's Pioneer started using output IC's instead of discrete transistors, in the SX-780 for example. Most of those ICs are no longer available. Pioneer's higher powered receivers from the same time period continued to use discrete components. Having said all that, you may never have a problem with an output IC, but they are known to be problematic. The Kenwood KR-9600 is an example of a high powered receiver, 160 watts RMS per channel, that uses output ICs. About a year ago I saw a replacement IC for that model on eBay for $125.00. The bottom line is that the discrete component designed amplifiers can still be repaired, where the output IC designed models cannot.
04-12-05
Q: My question is about recording speed.
I have been recording with a 4 track unit pretty much
my whole life. Now I have a 2 track unit with a much
slower speed. I've gone from 3/34 to 1/78, what i am
seeing is that the needles on my meters don't react as
fast, is this caused by the slower speed? Also should I
be able to record at the same level on the meters or
not. It seems like when I try to record at the same level
as I would normaly do the tape gets saturated and noisy.
Any help would be apreciated. thanks jay.A: Hello Jay,
Meter ballistics have nothing to do with tape speed. Your recording level
may be different depending on the alignment of the new deck. You should
align the new machine for the tape type you are using.
03-30-05
Q: I'm looking to purchase a vintage receiver Sansui or Pioneer maybe a kenwood made between 77-80. Could you tell me good ones to look for that repair parts are available? Also I've read one of your responses about having the tuner aligned and switched cleaned and or lubed, What does this cost and can any electronic shop do it? Thanks Dennis
A: Hello Dennis,
Parts are available for most receivers, with the exception of cosmetic parts such as knobs or model specific parts such as meters. Make sure you get one that is original and complete. Unfortunately, not every shop can perform the required service. Make sure you have some sort of proof of competent servicing. A competent service including tuner alignment will cost $100.00 and up.
Look for any Pioneer receiver from the mid 70's, such as the SX-838, or from the late 70's such as the SX-1050. Avoid the later, lower power receivers.
Look for the Sansui 7070, 8080, 9090 or separates such as the AU-717 and TU-717.
We do not deal in Kenwood, so I have no recommendations other than to avoid the KR-9600.
If you have something specific in mind, let me know and we can probably get it for you.
03-23-05
Q: I could sure use some help.
I've just purchased a Pioneer Spec 2 Amp. The amp upon start up sequence does this:
1. Protector lamp lights.2. Right side power meter deflects upscale(doesn't matter if the amp input/output is connected)-degree of R/channel deflection depends upon how long between re-starts.
3. If the time between starts is long enough, 2-4 minutes the meter sits about 1/4 deflected and drops down to zero when the protector circuit disengages-if I try to re-start the amp imediately, the protector lamp will not extinguish, the meter sits 2/3's upscale and the amp is muted-it will not operate.
4. The amp on shutdown exhibits some R/channel decoupling noise-right channel only.
5. Once the protection circuit disengages(cold start, wait 5 minutes or so), the R/channel deflects a little, the amp plays beautifully.
6. I looked at the schematic, the power supply excitaion scheems are more complicated than your typical amp, is there a possible voltage (leakage, offset) appearing at the output of the amp that is driving the meter?
7. I was going to check the bias settings, on the basis that perhaps the bias is sitting up on the border line-engaging the DC dectector (adjust VR1) but I'm not sure from the schematic I have what pin numbers on the amp board to use because they are not referenced by number, they're just depicted. If I follow the drawing the meter appears to be placed across the emitter/colector rails of the output transistors-would that be correct?
As you can imagine I'm really disappointed however, I don't want to risk further damage to the amp, if you recommend I'll send it out for service rather then poking around and blowing some impossible to get "matched" transistor.
I very much appreciate your time and effort in response.
Thank you,PeteA: Hello Pete,
I just spent a good part of the day troubleshooting a similar problem on an SX-1010. The problem was related to leakage in the class A transistors that are at the input to the amp section. The symptom was very similar; chaos upon power up and then an apparent stabilization.
If the problem only occurs in one channel, I would suspect a similar scenario. Most power supply problems manifest themselves in both channels at once. Given the current and voltage potential of the SPEC 2, caution is advised. Unless you have a fair amount of test equipment, specifically a Variac, O'scope and a schematic at minimum, I wouldn't recommend fooling around too much.
03-15-05
Q: I recently purchased a Marantz 2250B which works fine but had the usual dial lamps inop and one or two function lamps inop. No big deal I thought, I've replaced lots of Marantz lamps on several different models, so I paid the cash and took it home. When I opened the unit up, which was pretty dusty, but no real corrosion (again no big deal), I saw that the plastic bezel that the fuse lamp panel fits into was melted. A few of the bipin lamps were broken off, or also melted...it looked more like heat damage. Now I've read the pros and cons of replacing 200m/a bulbs with 250m/a ones...I can't read the value on the bad lamps I removed. The question(s) is/are - can the wrong lamps really cause meltdown? (if they are, in fact the wrong ones)- or should I look elsewhere for the meltdown? like general overheating from poor previous storage or excessive dust and such? Or something I'm not thinking about?
Thanks,
JimA:Hello Jim,
Incorrect lamps can melt the surrounding plastic, but they have to be pretty far out of original spec to do it. Some models were prone to damage due to design problems. Sounds like your 2250B spent a lot of time in the "on" mode.
03-06-05
Q: I bought a Marantz 1550 receiver from a guy on ebay last year and the unit
worked fine for about six months. Now it is giving me some problems such as
a loud popping sound when it is turned on, and the left side channel output
dropps off drasticly but can be corrected by grabbing the unit on both sides from the sides and bottom at the same time. (wierd huh?) and finally
the lights on the front panel are dimming. I paid about $200.00 for it. Do you think it would be worth it to have it repaired?
thanks...SteveA: Hello Steve,
As the saying goes "in for a dime, in for a dollar". A competent repair will run you $100.00 and up, but you'll end up with something that should last you a very long time. Given the rising cost of classic gear, you may actually end up even over time.
03-05-05
Q: I hope you can help. Back in 1984, I purchased a JVC A-X50 intergrated amp thats about 65 wpc. I have a seperate tuner and equalizer from the same company. These are connected to a pair of Polk Audio RTA 12c's. When the volume control goes to "3" (out of a possible 10) the system shuts down. I know the amp is 8 ohm and the speakers are 4 ohm, but I like my music cranked up and I can't get it with this system. Short of buying a seperate Adcom amp and power amp for $1500.00 any less expensive options. I want these speakers to rock. I've been living with this cut off at volume contol #3 for 20 years. It's like having a Corvette with a 4 cylinder motor. I took the JVC over the guy trying to sell me Harmon Kardon. I know, should of taken the salesman advice. Please give detail explanation in your advice as I'm totally ignorant when it comes to stereo's.
A: Hello Tony,
65 watts RMS per channel should be plenty, unless the JVC is not capable of driving a 4 ohm load. Try hooking the Polks up in series to one channel
(that means taking the two speakers and connecting the + of one speaker to the JVC left channel +, then take the other speaker - and connect it to the JVC left channel -, then run a wire between the unused + of one speaker and the unused - of the other).
That will produce an 8 ohm load for the left channel of the JVC. If it still shuts down then the JVC is suspect.
03-04-05
Q: I have inherited a Marantz model #2230. Thats the good news. The bad news is that it has two problems. The first problem is a broken stem on the treble control. Where could I find a treble control assembly and the knob? I currently work the treble control with needle nose pliers. The second and worst problem is that the left channel cuts in and out. The symptoms are as follows: The left channel will periodically work for about 5 minutes and then cut out. When it cuts out there is a god awful loud static noise in the speaker. I have cleaned out this unit very well and cleaned the controls with DE-OX-IT to no avail. Additionally, I have been unable to find any cold solder joints. When it was playing it sounded great. Also, I noticed that when the unit was off and I connected the speaker to the left channel I got some kind of static hiss out of the speaker. I have kind of "adopted " the unit and would very much like to fix it. Although I am not an experienced electronic tech I am an electrical engineer by degree and have a base knowledge of both passive and active devices. I also am familiar with test equipment. I just lack the pratical experience. This would be a good learner for me. Any assistance you can offer will be appreciated. I will soon have the service manual for this unit. Thanks.
A: Hello Tim,
You will need to find another 2230, or similar model, to obtain the treble control and knob.
Consider placing a 'wanted' ad: http://www.classicaudio.com/wanted
Isolate the noise problem by separating the preamp and amp sections using the "pre-out/main-in" jacks. Chances are the problem is in the amp section, and related to one or more bad transistors and/or capacitors.
02-15-05
Q: My question is about heat. How much heat is too much? My system is in
a glass enclosed cabinet, I put a small thermometer in there just to
get an idea of the heat. It was 115degrees inside, is this too hot?
Thanks jay.A: Hello Jay,
Yes, I would say that is too hot. I like to keep all electronics under 90 degrees.
01-30-05
Q: I recently purchased a Pioneer SX 1050 to use as an interim replacement
for my ailing Phase Linear amps. I'm thinking now this was a huge mistake.
At any output above background music level this unit produces nothing but
severely clipped,totally unlistenable,garbage.I bought the unit on E-Bay and the seller is reluctant to refund my money.Any comments/suggestions on the diagnosis/repair of this unit would be greatly appreciated.Sincerely,
Ed
A: Hello Ed,
Separate the preamp from the amp section by removing the "pre-out/main-in" jumpers. You can now power another amplifier with the 1050's preamp section, and drive the power section with another preamp. That should tell you where the problem lies.
Follow Up: Ed turned out to live near my shop, and he brought the SX-1050 over for diagnosis. The amp section was clipping on one half of the waveform, both channels, just past the 1 watt level.
01-24-05
Q: Hi...I have a Scott Stereomaster 342 solid state receiver, and it has a 50hz hum, low volume, out of both channels, which is not affected by the volume control at all. Any hints? Thanks.....
Hello Dan,
A: Three words: power supply capacitors
01-20-05
Q: I have a Pioneer SX-1050 receiver, it works well,but when you turn the volume all the way down, there is some static and sometimes crackling coming from both channels. It will sometimes put the thing in protect. The idle current is right at 50 mv. but when checking the DC offset, it is all over the place on both channels, the right being a bit more erratic than the left. I am assuming this is a power supply problem since it is both channels, but also why I am asking for your help. Also, when you switch the tone controls on or off, there is a pretty good "thump" through the speakers and sometimes trips the protect circuit as well. I have replaced the tone control circuit with a known good one, and still the same problem. Thank you in advance for your help, let me know what you think. Thanks alot....Norm.
A: Hello Norm,
The static symptom is usually an indication of a problem in the amp section, but you should be able to see variations in the power supply voltages if that's where the problem is. The thump symptom is usually an indication of a problem in the tone circuit, a shorted electrolytic cap. Check for voltage on the switch, there should be none, and check for voltage at the input and output of the tone circuit.
R: Norm here, onthe sx-1050with the static and popping problem. BTW, this is my home e-mail, the other was work. Anyway, mjust wanted to let you know, the problem was a leaky transistor on thepower supply board. It wasn't shorted or anything, but it checked wierd with a meter, so I replaced it and all was well.....I set the idle current and DC offset and it sounds great!! I found it with your tip of fluctuating voltage.....it was letting DC get on the tone control supply voltage as well.....Thanks a ton for your advice. I hope to talk to you soon.....you have been a great help!!
01-13-05
Q: I just went to components after many years of receivers and am having a power amp problem. I am using a Carver M-1.5T amp, C-1 preamp and Luxman T-117 tuner. The M-1.5T has a very slight but noticeable electric current or electric vibration feel when on and touched--like a hum you can feel but not hear. It does not produce an audible hum or buzz through the speakers (Klipsch Forte). This vibration goes through to the C-1 preamp because it was stacked on top of the amp. Separating the two units with rubber blocks, turning what plugs I could, trying other outlets, even changing out the interconnect between amp and preamp from a braided one to "regular" one does no good.
As I said, if you didn't touch the rack handle on the amp you would never know it was happening, and even then it is very faint. The system plays and sounds great with no hint of sound degredation. I do not have a multimeter or any way of testing, but my question is: am I doing any damage, especially to the Klipsch speakers, by just forgetting about it or should a certified tech see it immediately?
Thanks a lot for your help. I'd hate to ruin any of these components.
Bruce
A: Hello Bruce,
Due to the design of this amplifier, 60 cycle vibration is normal. Many times the vibration, which is created by the power transformer, turns into an audible buzz.
01-11-05
Q: I'm a DJ, and run a Numark CD-Mix2 mixer/cd player through a Crown Power Tech 2 into a pair of Steelsound Eminence loaded speakers, with 15 Delta woofers and APT-50 tweeters. The amp is rated at 300 watts RMS, the speakers at 500. Not too long ago, I popped a tweeter, running with the amp all the way up but the sliders on the mixer down below unity. I don't think anything was running in the red and I didn't hear any distortion, but one of the tweeters blew, just stopped putting out. For my next gig, I stuck in a cheap horn tweeter after the capacitor, and ran at a very moderate level, with the amp halfway up and the mixer way down. It was a 25th anniversary, no need to thump very hard. As I was talking to the husband, I detected a drop in treble. Another tweeter down. A friend of mine in the PA business replaced it with a pretty heavy duty tweeter and also a real crossover. Next came a little louder gig -- actually included some hearing impaired folks who wanted to "feel" the music. Great. Well, same thing, although it took a little longer. Still, I was watching and listening carefully for distortion, and didn't catch anything more than a transient into the red, which I quickly corrected. Everytime it's been that same speaker, though I'm not sure if it was always hooked up to the same channel on the amp and/or the mixer. My friend checked the amp for DC offset, and only detected something minuscule like 0.4mv. I'm thinking of doing my next gig with my backup amp and old speakers, but I'm afraid it could be the mixer. It was recently repaired by a pro for a mechanical problem with the drawers. A washer did fall in during the repair, and when I brought it back, a connecting cable attached to one of the sliders did come loose for a moment while it was opened up, but was quickly reattached and all the connections seem fine. But I still suspect the Crown, since it is used but a pretty recent addition to my system. Any thoughts? Thanks very much!
A: Hello Tom,
The number one cause of tweeter failure is amplifier clipping. Have the amp checked for power and distortion. Of course the amp will dutifully reproduce any square waves that it is fed, so the entire system should be checked for distortion. You may also want to consider putting a "brick wall" limiter in the amplifer's input path to eliminate any harmful transients. In the mean time, put a 1 amp fuse in series with the tweeter. That may save you a few gigs.
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