Jump to content

Easy Does It


Recommended Posts

DJK,

O.k. I did the test again as you said. I couldn't turn it up very loud though, my girlfriend was on the phone. Here it is.

In stereo:

40Hz/ 1KHz

Left .129v and .139v

Right .172v and .188v

In mono:

Left .052v and .051v

Right .054v and .054v

I guess the problem is just in stereo mode(?)

Tom

Link to comment
Share on other sites

Guess I have to get hold of Everett Audio Repair in Washington (they are the only ones doing authorized Carver service). I sent the unit to them a couple of months ago. For a flat rate fee they are supposed to do everything to it save for cosmetics, a new pc board and/or transformer. When I got it back they said they put in a new volume control and new speaker relays (it was dropping channels at low volume).

Thanks a bunch,

Tom

Link to comment
Share on other sites

mdeneen

Well, it started about 8-10 years ago and I just recently got fed up with it. It's being measured at the speaker terminals with speakers connected in AC volts. This is from the speakers's terminals and no the amps. The VOM is auto ranging and in this test it was in millivolts. I realize this isn't much current for a good measurement but it's all I could do and not get the little woman miffed. It was done with a noise generator from an old analyzer (HH Scott 830z from about 1978 or so)and there is no balance adjustment on it. It's really not a pink (white) noise but sounds like some alien space Hovite landing. It oscillates about 10 times a second.

There are two led meters on the receiver and the left one does not read as high in stereo mode. Out of seven steps in the meter the left channel is on average one step behind. I can tell the difference barely as well. I've tried changing speaker cable (from 16ga. lamp cord to 12ga. Monster Cable), different eq (previous one was fried anyway), new interconnects (from the cheap factory ones to Monster Interlink 300's) and took the 3bx out of the loop (plan to keep it that way). So the only thing that has remained constant is the receiver. This must be a high current amp because I'm not sure if I want to be around with this thing at one watt. On this thing it's that's about 12 o'clock.

If you need more info I'll try to get it to you. I'm not as techie as my sibs (General Electric Aircraft engineers and the like) but some of it did trickle down.

Link to comment
Share on other sites

I got the resistors now. Please bear with me. Do I just connect them to the terminal on the speakers from pos. to neg.? or between the pos. and neg. of the speaker cable at the speaker end without being attached TO the speaker. OR just to the pos. end of the cable in series to the pos. terminal on the speaker. Sorry if this wasn't obvious to me. Thanks!

Tom

Link to comment
Share on other sites

Well that took a while to do. Had to let the resistors cool down for 10-15 minutes at a time. This a lot of info so I hope it goes in a decipherable direction. These are the readings and notes I took. If you want I can e-mail the Excel file.

The 10v readings were noted as an average due to lack of stabilization.

0.1v / 1.0v / 10v

Left Channel

20 Hz .102 / 1.002 / 9.91

200 Hz .099 / .988 / 9.92

2kHz .096 / .994 / 9.93

20kHz .102 / .987 / 9.86

Right Channel

(Control Reading)

20Hz .102 / 1.005 / 10

200Hz .099 / 1.004 / 10.05

2kHz .097 / 1.004 / 10.02

20kHz .102 / .998 / 9.99

Average deviation: -.0395833v

Notes: Values are given in AC Voltage.

Volume on receiver: Max.

Loudness: Off.

EQ: Flat but engaged to +/- 6db range.

Frequency selected for test was set at +6db.

Stereo mode selected.

Balance: Centered at all times.

Some of the control values are not at an exact "whole number" but it was as close as I could get it. After I re-read your last message I saw that you said to have all amp levels to maximum. Did you mean just volume (that's what I did) AND tone controls (because I had them disengaged as well as the loudness).

Let me know!

Tom

Link to comment
Share on other sites

-mdeneen

Thanks for all your help! If sending a six pack through the mail was allowed I'd do it.

Is there a way to tell at what point the amp would clip? Some sort of I/O test? This one is rated (conservatively) at 150/wpc but I've read articles of the 130/wpc model creeping up to 164/wpc. Maybe there is an adjustment on a mini-potentiometer pot inside the unit to center the output meters. For now I'm blaming the fried tweeters on the 3bx. It's old and dirty (inside) so there may have been the combination dirty connections and over-db(ing) the speakers. The new drivers are in so maybe I'll take the bulbs out. Do you know of a specific value of fuse that would work for this. An in line fuse holder sounds to be a cleaner design than the contraption I put in there a few days ago.

Tom

Link to comment
Share on other sites

I'm sure mdeneen means well but he isn't helping you.We already determined that there was nothing wrong with your amp.We did determine that you had a bad volume control.Measuring channel balance with the volume control wide open is pointless. Unless you listen that way.All that is important is the channel balance in the normal range that you listen in.Your measurements indicated a 2~2.5dB imbalance at the volume level you were measuring at.>>In stereo:

40Hz/ 1KHz

Left .129v and .139v

Right .172v and .188v

In mono:

Left .052v and .051v

Right .054v and .054v<< The stereo mono switch is after the volume control and closed feeds the amp exactly the same signal.Obviously the amp is OK and the volume control doesn't track.

Putting the resistors on was pointless.An amplifier is a constant voltage source.At levels below clipping it will keep the voltage the same no matter what you use as a load.It will measure the same voltage into 4,8,16,or an open circuit.>>FWIW, bulbs in your circuits add considerable series resistance << Oh really? Pray tell how much? Most lightbulbs exhibit cold to hot ratios of more than 20:1 That means it is like it isn't there unless you are clipping the amp.>>I think 3A fast acting would be my starting point. If this blows at what seems like lower volume than is possible with your speakers, try 5A.<< A 3A fuse offers litle or no protection.A 5A fuse would never blow.A Klipschorn has a 5.5 ohm minimum impedance ~250hz.I used to demonstrate how low the average power was in music by wiring a 1A fuse inline with a 200 watt MC2205 and turning up the volume until the meters were banging against the end stop and the red powerguard light came on.The fuse held.How big of a fuse do you think he needs? Sell me the DBX if you are just going to let it collect dust.

Link to comment
Share on other sites

Just my thoughts, you might be overdriving the input stage to yur power amp. and introducing clipping there. If so you would blow tweeters at normal loud listening levels. i.e. your signal is clipped no matter what volume you set your amp to.

it could happen...

Regards,

bill rawls cool.gif

Link to comment
Share on other sites

This may sound dumb but here it goes. Has anyone ever considered to check the X-Over to make sure it's doing it's job correctly? A bad X-Over can fry a horn tweeter fast.

------------------

Onkyo TX8511

ADCOM GCD-700

KLIPSCH CF3,s

KLIPSCH CF4's

KSW-300

Link to comment
Share on other sites

djk:

First, a MC2200 does not have meters!!!!!!

Second, I blow 1 amp fuses all the time with my Belles (added in-line fuse) using amps as small as MC225.

Maybe you need to hook speakers up to that amp.

Regards,

bill rawls cool.gif

Klipsch Belle

Klipschorn

Altec A-7

MC2105

MC225

Dynaco Mark III's

Dynaco ST-70

Audio Note Kit 4

and a lot of 1 amp fuses......

Link to comment
Share on other sites

Have you talked to Trey? He helped me out the other day. He would have some insight I'm sure. I haven't had the same problem but if I were I would...

1. Switch speakers (you know, switch your left channel speaker to your right and vice-versa)

2. Remove all sound manipulators...e.g. EQ

3. All tone controls set to 0

4. Run'em hard

You see I can't imagine having to run a lightbulb or anything else inline to keep from blowing speakers. You need to find the real problem and fix it. It may be the Carver it may not. I'm not a genius like some of these guys helping you I just think that there is a problem. Call Trey and talk to him about the X-Over, I couldn't tell you how to test the X-Over so I don't even want to try. I discovered I had a bad X-Over by isolating the horn and listening. Then I switched horns and the other horn did the same thing...there are only two things in a speaker that can be bad, a X-Over or the speaker. Unless of course there are unusual components that I'm sure someone will point out to me. I've read this thread and boy you would think that us regulars on the BB could give our suggestions and try to help. Not be a know it all. I'm not saying that I know how to fix it I'm just offering advice from my experience. You might want to borrow another receiver from a friend. I run a CD player, DVD and that's it. Just power and source. I try to keep it clean. A long time ago I ran an EQ and it added a POP in certain passages of certain songs. I traced it to the EQ and eliminated it. I didn't even have it adding anything, all settings were at 0, I just had it in the loop for the spectrum display. ( dancing lights looked neat smile.gif ) I hope I have helped and not confused or offended anyone. Lets keep this BB a friendly one.

------------------

Onkyo TX8511

ADCOM GCD-700

KLIPSCH CF3,s

KLIPSCH CF4's

KSW-300

Link to comment
Share on other sites

We are all here to help. Most of us work hard and we play hard. Just as in NASCAR we bump and rub - it is all in good spirit and fun. At the same time we help each other. I think this is understood.

We do not need self-apointed forum monitors.

If you don't want to play with the big boys, stay off the playground.

I don't take offense if someone pokes at me and I mean no offense if I bump someone else in a curve. It is how men work and play.

Bob G will let us know when we get out of hand.

Regards,

Bill Rawls cool.gif

Link to comment
Share on other sites

quote:

Originally posted by bill rawls:

We are all here to help. Most of us work hard and we play hard. Just as in NASCAR we bump and rub - it is all in good spirit and fun. At the same time we help each other. I think this is understood.

We do not need self-apointed forum monitors.

If you don't want to play with the big boys, stay off the playground.

I don't take offense if someone pokes at me and I mean no offense if I bump someone else in a curve. It is how men work and play.

Bob G will let us know when we get out of hand.

Regards,

Bill Rawls
cool.gif

LOL

------------------

Onkyo TX8511

ADCOM GCD-700

KLIPSCH CF3,s

KLIPSCH CF4's

KSW-300

Link to comment
Share on other sites

mdeneen--

Ya know, a sweeping signal is about the only thing this old H.H. Scott doesn't have. I can't complain about much though. Only paid a C note for it 17 years ago and used to sell for a grand. Pretty sure the friend who's gonna check it out has one that does.

To All--

I really do think the bias problem and the blown tweeter problem are mutually exclusive.

The bias problem was there even when the receiver was driving four other speakers and a sub.

The first blown tweeter(s) I'm almost positive that was from keeping the eq at the same settings for the old speakers and the second one was from the 3bx and a hot signaled cd from the girlfriend (I'm not tellin' her that smile.gif ).

Didn't mean to stir up any heated debates of what it might be but as we used to say in the auto parts business "Hold the phone closer to the car so I can SEE what the problem is". It's just tough to do.

BTW-- Does anyone know of an equipment (stereo) rack, ya know the kind that's only 19" wide on the inside and all your stuff can just bolt into some mounted angle-irons on the component's rack ears? I'd like to have one that is furniture grade, not industrial looking, on casters and 22" deep or more. The closest thing I found is from Middle Atlantic Products but it's gonna cost a bundle when all the parts get assembled (around a grand or so!!). I didn't want to go with the shelf type cabinets but if I must the closest one to fit the bill is from Studiotech called a U-48 or U-60. There again $1,200.

Thanks guys.

------------------

Tom

KLF-20 Mahogany

Carver Receiver MXR-150

Yamaha PF-800 Turntable/ Sure V15 Type V Cartridge

Carver TL-3100 CD

Yamaha K-1020 Cassette

dbx 1231 EQ

dbx 3bx Series Two (mothballed)

H.H. Scott 830z Analyzer

Monster Interlink 300 mk II

Original 12ga. Monster Cable

dbx 200 (mothballed)

dbx nx-40 (can't beleive I still own this thing! Mothballed)

Technics R&B Series SB-7 (mothballed)

Technics R&B Series SB-3 (mothballed)

Yamaha NS-W2 (mothballed)

SAE 5000A (mothballed but perfect shape)

Link to comment
Share on other sites

>>First, a MC2200 does not have meters!!!!!!<< Yeah Bill,you're right.I went back and edited it to read MC2205.I guess the point was that a 1A fuse can pass 300W peaks without blowing.BTW the fuse would blow instantly if you turned off the powerguard.I really feel that the lightbulb is the answer for people that like to play it loud every now and then.Klipsch had such a problem with their KG tweeter diaphragms blowing that they started putting .9A self resetting fuses (Raychem PolySwitches) in some of their models.These are too slow/too big to work 100% of the time so I resorted to the 561 lightbulb trick.I did this back when the diaphragms were $4 each.Now that they are $40 a pair.....>>BTW-- Does anyone know of an equipment (stereo) rack, ya know the kind that's only 19" wide on the inside and all your stuff can just bolt into some mounted angle-irons on the component's rack ears? I'd like to have one that is furniture grade, not industrial looking, on casters and 22" deep or more. << Just buy the rack rails from Mid Atlantic and bolt them into a furniture rack.18 space rails (31.5") are only $20 a pair.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...