I was wondering if anyone could answer an amp / speaker question. How can I determine if I have a problem internally in the QLS that could potentially be causing amps to blow? I previously had a Nikko Alpha 1 and a Hafler 120 horizontally bi-amped and after 3 hours of moderate volume I lost the right channel in the Nikko. It was hooked up to the bass. So I decided to pick up a pair of Adcom GFA 555's, and I am planning to vertically bi-amp. I have one Adcom hooked up to the left speaker, with one channel into the bass and the other channel into the mid high. I am waiting on the other Adcom which will be here in the morning. I was getting all my wiring ready, etc, and I had the left speaker only running. No patch cords or speaker wires were hooked up to the right channel. It sounded great (for one channel). After letting it run for a couple hours again at moderate volume, I started to hear a crackle coming out of the speaker. I immediately turned everything off, but I am afraid I may have done damage to my amp that I just got. Does anyone have any ideas as to what could be going on? Could I have a problem in my crossovers? I'm sure I have the connections right. If I blew another amp I'm going to be a little upset. If I have a problem I don't want to even hook up the other Adcom when it arrives until I have fixed the problem. Help!

RH speaker Bass section killed the Nikko RH channel.

LH speaker killed the Adcom. Which part of the speaker killed what channel of the Adcom?

Did you have the speaker straps disconnected ? (small wire between the two sets of binding posts at the back of the speaker).

Can you provide a schematic of exactly how you had the components wired?

It seems strange to me at this point that both speakers are causing amp failure, and will be stranger if it is both bass sections. We'll wait for that confirmation.

tlgibbs, have you checked the amps to make sure it's not the fuses that have blown? That would of course be the best scenario, because the amps themselves could be still ok.

Man, this is not good. I feel for you. Hopefully the troops will rally :yes:

[QUOTE=Kencat;1387103]

RH speaker Bass section killed the Nikko RH channel.

LH speaker killed the Adcom. Which part of the speaker killed what channel of the Adcom?

Did you have the speaker straps disconnected ? (small wire between the two sets of binding posts at the back of the speaker).

Speaker straps are definitely disconnected.

Can you provide a schematic of exactly how you had the components wired?

I don't know how to provide a schematic, but I will try to verbalize: I have the left pre-out from the receiver split into two. Each of the two resulting pre-outs is input into the Adcom, one into the left in and one into the right in. The two speaker outs from the Adcom are wired to the QLS, the left channel into the bass terminal posts and the right channel into the mid high terminal posts. I believe that this is the correct configuration for a vertical bi-amp, no? I don't think it matters whether the left Adcom output goes into the bass or mid high, or the right goes into the bass or mid high, as both Adcom channels receive identical input from the pre-amp (which was split).

Further, it should not matter if I am powering the left channel, the right channel, or both, since each channel has it's own amp. Currently only the left speaker is being driven.

It seems strange to me at this point that both speakers are causing amp failure, and will be stranger if it is both bass sections. We'll wait for that confirmation.

tlgibbs, have you checked the amps to make sure it's not the fuses that have blown? That would of course be the best scenario, because the amps themselves could be still ok.

I turned the system back on briefly, and everything is working normally. However, I don't trust the setup. Could it just be a overheating issue? The Adcoms have available optional auxiliary fans, but I don't have them. Maybe driving the QLS for several hours causes too much heat buildup? The amp is completely out in the clear, with no obstructions above or beside it.

Man, this is not good. I feel for you. Hopefully the troops will rally :yes:

Thanks

tl,

I was rereading your other post again. You mentioned you had the Adcom bridged for mono. Is this what it failed on? The wiring could be a bit more complicated if this is the case. Also, bridged mono reduces the low impedance ability of the amp.

The single Adcom should have been able to power both speakers at normal to sort of high volumes by itself in stereo mode. The QLS-1 shouldn't be that much more of a load that my Q2's....I don't think????. The Adcom distortion indicator lights should have been lighting up as well if something was amiss, or the fuses just popped.

I've never seen my Adcom blip a light on ever.

EDIT: Tlgibbs - I posted this before seeing your response. If it seems out of context, that is why

I was wondering if anyone could answer an amp / speaker question. How can I determine if I have a problem internally in the QLS that could potentially be causing amps to blow? I previously had a Nikko Alpha 1 and a Hafler 120 horizontally bi-amped and after 3 hours of moderate volume I lost the right channel in the Nikko. It was hooked up to the bass. So I decided to pick up a pair of Adcom GFA 555's, and I am planning to vertically bi-amp. I have one Adcom hooked up to the left speaker, with one channel into the bass and the other channel into the mid high. I am waiting on the other Adcom which will be here in the morning. I was getting all my wiring ready, etc, and I had the left speaker only running. No patch cords or speaker wires were hooked up to the right channel. It sounded great (for one channel). After letting it run for a couple hours again at moderate volume, I started to hear a crackle coming out of the speaker. I immediately turned everything off, but I am afraid I may have done damage to my amp that I just got. Does anyone have any ideas as to what could be going on? Could I have a problem in my crossovers? I'm sure I have the connections right. If I blew another amp I'm going to be a little upset. If I have a problem I don't want to even hook up the other Adcom when it arrives until I have fixed the problem. Help!

I am paying close attention to this thread.....I have had this happen to me...... after tripping circuit protection relays on my amps. It sounded like I was listening to music through amplified rice crispies. Snap crackle and pop. I hooked it up to a different speaker and the sound was the same, snap , crackle and pop.... I thought I had blown the amps...... I turned everything off fora while. When I turned the stereo back on I used my tuner instead of CD it sounded fine. So I thought it might be the cd .....after trying the tape deck it was ok too , by the time I tried CD again it sounded normal. I havent run it for hours since ....I pray it doesn't return. Don't know what the hell it was ( amps preamp or CD player but it wasn't good.) Gave the same kind of symptom as a dirty volume control pot.

Do you have any other speakers to try??? See if it still happens to another set. Process of elimination!!! I hate these things especially if they are intermittent. Good luck feel for ya!!

[QUOTE=Kencat;1387138]tl,

I was rereading your other post again. You mentioned you had the Adcom bridged for mono. Is this what it failed on?

No. I only had it bridged for mono for a very short period of time. Currently the lever is switched to normal or stereo mode.

The wiring could be a bit more complicated if this is the case. Also, bridged mono reduces the low impedance ability of the amp.

The single Adcom should have been able to power both speakers at normal to sort of high volumes by itself in stereo mode.

Right. It is in stereo mode but both channels of the stereo are going into one speaker. I'm preparing for the arrival of the other Adcom which will power the right speaker.

The QLS-1 shouldn't be that much more of a load that my Q2's.... I don't think????.

I wouldn't think so either...

The Adcom distortion indicator lights should have been lighting up as well if something was amiss, or the fuses just popped.

I've never seen my Adcom blip a light on ever.

EDIT: Tlgibbs - I posted this before seeing your response. If it seems out of context, that is why

[QUOTE=Augy;1387158]I am paying close attention to this thread.....I have had this happen to me...... after tripping circuit protection relays on my amps. It sounded like I was listening to music through amplified rice crispies. Snap crackle and pop. I hooked it up to a different speaker and the sound was the same, snap , crackle and pop.... I thought I had blown the amps...... I turned everything off fora while. When I turned the stereo back on I used my tuner instead of CD it sounded fine. So I thought it might be the cd .....after trying the tape deck it was ok too , by the time I tried CD again it sounded normal. I havent run it for hours since ....I pray it doesn't return. Don't know what the hell it was ( amps preamp or CD player but it wasn't good.)

Yes, and I have turned the system back on twice now for brief times, and everything seems to be normal.

Gave the same kind of symptom as a dirty volume control pot.


Hmmm..... Interesting. Possibly the problem is in the pre-amp (receiver)?

Do you have any other speakers to try???

Yes, but I have not tried them yet. I'm hesitant to run the amp until it acts up again -- don't want to damage it

See if it still happens to another set. Process of elimination!!! I hate these things especially if they are intermittent. Good luck feel for ya!!


Thanks

My 2 cents..Don't these particular speakers require a very robust amplifier which is 2 Ω stable to drive the bass ?:scratch2:

Dave

[QUOTE=avionic;1387239]

My 2 cents..Don't these particular speakers require a very robust amplifier which is 2 Ω stable to drive the bass ?:scratch2:

Yes they do. That is why I chose the Adcom. It is stable down to 2 ohms

I've been reading pdf manuals on the GFA 555II and GFA 555. They do not employ any electronic or current limiting circuitry on the outputs. They only use fuses on the DC rails. There is also a thermostat that cuts out power to the transformer if temp exceeds set point, and it will reset once the temp is back down. All this doesn't sound like it would cause crackling; it would be a total power outage.

Augy, I believe you had a bad relay on the Nak though right? This would be acting like a bad contact and could cause all the snap, crackle, pop stuff, as you say like a dirty pot, but the Adcom doesn't have any output relays. You may be on to something though, it could be coming from the receiver (preamp) with a dirty switch, or any of the pots, or a source device (I have a tuner with a selector switch that will cut out a channel once in a while or cause it to sound bad).

tlgibbs, if you haven't already, download the manuals from the Adcom website. The GFA 555 manual sucks, get the 555II manual as well, it's well done with a lot of good info.

Running the Adcom on another set of speakers sounds like a good idea, especially if they are "normal" speakers, to prove that there is nothing abnormally wrong with the amp. Run with some other control devices as well. All the focus on the poor old amp though is forgetting that the Nikko also had trouble (although it is not nearly as capable as the Adcom). Is the Nikko permanently dead?

Seems like a lot stuff to check out here tlgibbs. And we haven't even talked about the speakers themselves yet.

Well, I found a problem. I don't know if it is the problem, but it is a problem. Some wise person once said "check the obvious stuff first." I found a bad patch cord from my cd player to my receiver. It had been hooked up forever, and when I gave it a wiggle it literally fell out of the back of the receiver. It was not making good contact. And yes it was the right channel. I don't know if this is the culprit or not, but I replaced the patch cord. I also went to good stereo shop and got some really nice high end patch cords with splitters to split the signal from the preamp to the power amplifiers. 70 bucks for a pair of "Y" adaptors and patch cords, but they are well insulated and the guy at the shop said it is what I need for this type of application. I got the second Adcom this morning and as we speak I have sound coming out of both of my speakers.:banana:

I am being pretty cautious for now. I don't want to push anything until I get more confidence in the whole setup. I'm keeping my fingers crossed. If everything works I will get pictures posted of the new setup if anyone is interested. Thanks for all the tips, especially kencat.:D

I love it when a plan comes together :thmbsp:.

Fingers crossed for ya that it all works perfectly.

If everything works I will get pictures posted of the new setup if anyone is interested. Thanks for all the tips, especially kencat.:D

Yeah, dang those simple problems eh? Heh, it was a team effort tlgibbs. I think Augy got the thinking going in the upstream component direction, which is where you most likely have found the problem. The more suggestions you get on an issue like this the better. One guys' thoughts make another guy think of something he wouldn't have otherwise. Even if an idea isn't exactly right, it sparks more thinking toward the right one. Hopefully you are all set now :D

OK, it's been 3 hours now, how's it going? What do think of the sound? Should be some nice tight deep bass rolling around there. In fact maybe you aren't even real impressed at the moment. Give em time and re-listen to some stuff you haven't heard in a while but you think you know pretty good.

Pics of your setup would be most appreciated I think :yes:

Now, next step - a real good pre-amp. There's some gold to be mined there for sure.

After replacing cables, isolating components, etc., I have good news and bad news. The good news is that as near as I can tell the QLS and the two new Adcom GFA 555's are A-OK. However..........

Apparently along with the bad patch cables I also have a bad receiver / preamp. The right channel is fried in my Yamaha cr2020, which I am using as a preamp. I have always liked it, but now I must either repair it or replace it. Any thoughts are always appreciated....... Thanks

Now, next step - a real good pre-amp. There's some gold to be mined there for sure.

Right now sounds like a good time for a good real pre-amp.

Right now sounds like a good time for a good real pre-amp.

:yes:

Don't skimp on it either. A really good preamp will make a huge difference in sound quality.