JBL Concert Speakers: power & Connections?

[kyrvas]

No, that is not a volume control, that is an input control to set the record level and not playback level.

The output level control will act as the volume control.

Glad I asked; that could have been bad! The Output Level control is sure a small knob, but important. . . . here it goes . . .

 

[kyrvas]

Disappointing results . . . let me see if I have this right: rcvr jumpers pulled -> cassette deck out/play connected to rcvr Main In -> power on rcvr -> power on cassette deck -> press play on cassette deck -> tape rolls -> Peak levels advance -> increase Cassette Output Level from 0 to 1 to 5 -> NO speaker output! Is it correct that the buttons on the rcvr have no control over the volume, or monitoring what goes to the speakers; nor does the rcvr Selector switch need be on a specific function, Tape, Aux, etc.???

 

[kyrvas]

Another question, I have been plugging the tape decks into the rcvr's Switched outlet; is that a problem?

 

[lovinthehd]

As long as you don't mind only having power to the decks when the receiver is on. The types of units you don't want to plug into the receiver's power outlets are power amps or anything else with large demands....

 

[kyrvas]

As long as you don't mind only having power to the decks when the receiver is on. The types of units you don't want to plug into the receiver's power outlets are power amps or anything else with large demands....

Thank you lovinthehd - overall it looks like the rcvr needs pro diagnostic help.

 

[lovinthehd]

One thing you might try before servicing is to work all controls, dials/buttons both, a bit to make sure the contacts are okay and not intefering with operation. Could have been put away for a reason, too.....

I had a similar Marantz receiver 40 years ago and it didn't last even 10, though.

 

[TLS Guy]

Disappointing results . . . let me see if I have this right: rcvr jumpers pulled -> cassette deck out/play connected to rcvr Main In -> power on rcvr -> power on cassette deck -> press play on cassette deck -> tape rolls -> Peak levels advance -> increase Cassette Output Level from 0 to 1 to 5 -> NO speaker output! Is it correct that the buttons on the rcvr have no control over the volume, or monitoring what goes to the speakers; nor does the rcvr Selector switch need be on a specific function, Tape, Aux, etc.???

You have that right. The receiver has a major problem. You need to seriously consider the cost/value of repair. It is a very old receiver and the cost of restoration will be quite steep.

On equipment that age, you don't just do a fix, but a total restoration. That will run into several hundred dollars.

I would look at what a good working restored unit would sell for on eBay. Those older receivers do have a following though, and people do pay good money for a good one. I'm not sure why, but they do.

I have never been a receiver guy.

You should now test that BGW amp and see of that is functional. If it is, I would get yourself a decent pre amp and forget receivers. I'm not a receiver guy and consider them a bad idea. In many ways they have been a road to ruin away from high fidelity audio.

 

[TLS Guy]

Another question, I have been plugging the tape decks into the rcvr's Switched outlet; is that a problem?

No.

 

[kyrvas]

One thing you might try before servicing is to work all controls, dials/buttons both, a bit to make sure the contacts are okay and not intefering with operation. Could have been put away for a reason, too.....

I had a similar Marantz receiver 40 years ago and it didn't last even 10, though.

Thanks - I probably have pressed most of the buttons except the filters because there was no sound to hear channel conflicts.

 

[kyrvas]

You have that right. The receiver has a major problem. You need to seriously consider the cost/value of repair. It is a very old receiver and the cost of restoration will be quite steep.

On equipment that age, you don't just do a fix, but a total restoration. That will run into several hundred dollars.

I would look at what a good working restored unit would sell for on eBay. Those older receivers do have a following though, and people do pay good money for a good one. I'm not sure why, but they do.

I have never been a receiver guy.

You should now test that BGW amp and see of that is functional. If it is, I would get yourself a decent pre amp and forget receivers. I'm not a receiver guy and consider them a bad idea. In many ways they have been a road to ruin away from high fidelity audio.

Okay, a new direction. I started this thread to simply power four (not necessarily at the same time) JBL concert speakers, determine that they work and sound good, and then determine their value for sale. They take a large footprint where we now have them and would be glad if someone bought them at a fair market price, AND they met their needs.

First, they need testing!

Regarding the BGW amp, can I connect the JVC cassette deck to the amp, then my small test speakers to the amp, then crank down the Output Level on the cassette deck; power them both on, then slowly increase the Output Level knob?

Is that what you mean by testing the BGW? Also, do I really need a pre amp?

 

[-Jim-]

Yes, the methodology we discussed for the Marantz would apply to the BGW. You don't need a Pre-Amp if you use the JVC KD-V6 as the source. Again turn the output (volume) control all the way down on the JVC KD-V6. Connect the Line Out (Play) RCA connector on the rear of the JVC KD-V6 to the corresponding Right & Left inputs on the BGW amp.

Connect the speakers as described earlier. Turn on the BGW Amp. Put a tape into the the JVC KD-V6 push play, and slowly turn the Output Level up. The sound should come through loud and clear on the JBLs.

 

[TLS Guy]

Okay, a new direction. I started this thread to simply power four (not necessarily at the same time) JBL concert speakers, determine that they work and sound good, and then determine their value for sale. They take a large footprint where we now have them and would be glad if someone bought them at a fair market price, AND they met their needs.

First, they need testing!

Regarding the BGW amp, can I connect the JVC cassette deck to the amp, then my small test speakers to the amp, then crank down the Output Level on the cassette deck; power them both on, then slowly increase the Output Level knob?

Is that what you mean by testing the BGW? Also, do I really need a pre amp?

Your best way to test them is via the BGW as you describe.

In terms of sale I have a feeling you think this equipment is worth more than it is.

First those speakers are not JBL speakers. They are custom or DIY speakers built with JBL parts. I doubt they are very good. For one thing they look way over ported to me. JBL pro speakers of the time using woofers like that did not have nearly that much porting. Back then this market was not aware of Thiel and Smalls paper. There were no modelling programs. So seldom would a speaker like that be much good.

The Marantz can go on eBay parts or repair. There are quite a few hobbiest restorers who would pick that up. I would put it up with an opening bid of $10.00

Now there are two ways to go here.

You could sell the speakers, BGW and mixers as a package deal to someone who wants to do disco.

The four speakers may be $100 each if you are lucky.

The BGW though highly regarded is one of their lower power offerings at 100 WPC. I have done an eBay search and would put a value of $150 to $175 for that amp.

The mixers hard to know, as the condition is unknown. There are likely noisy faders at least.

So if you sell it as a package may be $750 to $850 the lot.

The other option, and this will almost certainly get the most money is to part out the speakers.

If you sell the drivers as pairs and they are JBL drivers they all would probably make decent cash on eBay. There is always a good market for older drivers from restorers.

If the crossovers inside are JBL they will make money also. If not they are worthless.

If your interest is purely sale, then parting out the speakers will fetch you the most money, as long as the drivers are JBL and the model numbers are clearly visible and they all work.

 

[kyrvas]

One thing you might try before servicing is to work all controls, dials/buttons both, a bit to make sure the contacts are okay and not intefering with operation. Could have been put away for a reason, too.....

I had a similar Marantz receiver 40 years ago and it didn't last even 10, though.

lovinthehd - Rethinking your suggestion to work the controls, how about "deoxit" which I see mentioned on this site. I'm assuming it deoxidizes electrical contacts; not an omega-3 fatty acid antioxidant? Perhaps that could hold an answer to why no audio out to speakers?

 

[lovinthehd]

lovinthehd - Rethinking your suggestion to work the controls, how about "deoxit" which I see mentioned on this site. I'm assuming it deoxidizes electrical contacts; not an omega-3 fatty acid antioxidant? Perhaps that could hold an answer to why no audio out to speakers?

May help, may not....the receiver may simply be dead. When working the controls was there any audio at all, even static/scratchy sounds?

 

[kyrvas]

Yes, the methodology we discussed for the Marantz would apply to the BGW. You don't need a Pre-Amp if you use the JVC KD-V6 as the source. Again turn the output (volume) control all the way down on the JVC KD-V6. Connect the Line Out (Play) RCA connector on the rear of the JVC KD-V6 to the corresponding Right & Left inputs on the BGW amp.

Connect the speakers as described earlier. Turn on the BGW Amp. Put a tape into the the JVC KD-V6 push play, and slowly turn the Output Level up. The sound should come through loud and clear on the JBLs.

Okay Jim - that's my next step. Using what is available to me from my BIL gives me an idea that it functions. Regarding speakers, the JBLs are in storage about 35 miles away; so, I am using small 30 watt portable speakers for this testing in my house. Once this arrangement produces sound, I'll take it back to the JBLs and see (actually listen) for some beautiful sounds.

 

[TLS Guy]

May help, may not....the receiver may simply be dead. When working the controls was there any audio at all, even static/scratchy sounds?

It is beyond Deoxit. I had a look at the service manual last night. The is an excess current detector circuit, which activates a cut out relay. So the preamp and power amp are getting no power, but the radio is.

If he is not going to keep it, he will loose money having it fixed, assuming the power transistors are available. Most likely there is a shorted power transistor activating the cut out..

 

[kyrvas]

May help, may not....the receiver may simply be dead. When working the controls was there any audio at all, even static/scratchy sounds?

NO sounds, static . . . only lights and words on the display indicating that the Selector knob was on tape, aux, am/fm, etc., and meter needles moving.

 

[kyrvas]

It is beyond Deoxit. I had a look at the service manual last night. The is an excess current detector circuit, which activates a cut out relay. So the preamp and power amp are getting no power, but the radio is.

If he is not going to keep it, he will loose money having it fixed, assuming the power transistors are available. Most likely there is a shorted power transistor activating the cut out..

Good info TLS guy - am not pursuing repairs; either sell. if functioning. or the various items go to the electronic recycling here in CA. BTW, the Marantz rcvr is a beast at 40 lbs.

P.S. Just had an afterthought, since you are knowledgeable in the internal working components; could I test if the amps are getting power by using an Volt Meter on the speaker connectors?

 

[TLS Guy]

It is beyond Deoxit. I had a look at the service manual last night. The is an excess current detector circuit, which activates a cut out relay. So the preamp and power amp are getting no power, but the radio is.

If he is not going to keep it, he will loose money having it fixed, assuming the power transistors are available. Most likely there is a shorted power transistor activating the cut out..

Good info TLS guy - am not pursuing repairs; either sell. if functioning. or the various items go to the electronic recycling here in CA. BTW, the Marantz rcvr is a beast at 40 lbs.

P.S. Just had an afterthought, since you are knowledgeable in the internal working components; could I test if the amps are getting power by using an Volt Meter on the speaker connectors?

No.

I can tell you since both channels are dead it is not getting power. Otherwise you would have to entertain a fault in both channels. The power supply was quite complex and the protection advanced for its date. The output transistors are direct coupled which is unusual for receivers of that date. Since the output stage is direct coupled, protection needs to be robust, or the shorted transistor blows up the speakers, which at that time was a common occurrence.

After looking at the service manual something is shorted, and the most likely cause is a power transistor or power transistors.

Do not take that unit to a recycling center. Because of its age, the ethical thing to do is to make it available to an enthusiast restorer via eBay.

 

[kyrvas]

Your best way to test them is via the BGW as you describe.

In terms of sale I have a feeling you think this equipment is worth more than it is.

First those speakers are not JBL speakers. They are custom or DIY speakers built with JBL parts. I doubt they are very good. For one thing they look way over ported to me. JBL pro speakers of the time using woofers like that did not have nearly that much porting. Back then this market was not aware of Thiel and Smalls paper. There were no modelling programs. So seldom would a speaker like that be much good.

The Marantz can go on eBay parts or repair. There are quite a few hobbiest restorers who would pick that up. I would put it up with an opening bid of $10.00

Now there are two ways to go here.

You could sell the speakers, BGW and mixers as a package deal to someone who wants to do disco.

The four speakers may be $100 each if you are lucky.

The BGW though highly regarded is one of their lower power offerings at 100 WPC. I have done an eBay search and would put a value of $150 to $175 for that amp.

The mixers hard to know, as the condition is unknown. There are likely noisy faders at least.

So if you sell it as a package may be $750 to $850 the lot.

The other option, and this will almost certainly get the most money is to part out the speakers.

If you sell the drivers as pairs and they are JBL drivers they all would probably make decent cash on eBay. There is always a good market for older drivers from restorers.

If the crossovers inside are JBL they will make money also. If not they are worthless.

If your interest is purely sale, then parting out the speakers will fetch you the most money, as long as the drivers are JBL and the model numbers are clearly visible and they all work.

TLS Guy - this is more good info; I like being educated.

Yes, I naively I do think they are worth more. But a high price is not my main reason for selling.

JBL concert-style speakers: "seldom would a speaker like that be much good" but if they sound good (relative to the listener and the environment) and can project sound for a family outdoor gathering, or party, there may be an interested buyer(s). Please define "over ported". BTW, I only took a photo of one speaker cabinet; there are others with a JBL logo in the lower corner.

Marantz on eBay: wouldn't pursue that since they are heavy to ship, but maybe I can contact a local restorer.

"a package deal . . . Disco": that's a really good thought; which would help us (my wife's in this also) move this equipment.

The BGW amp: "$150 to $175" sounds reasonable.

Mixers: my BIL was using the Mackie Onyx1620 at his work station before he was hospitalized.
I have no clue how to test for a noisy Fader.

"sell it as a package may be $750 to $850" - another good sound to me.

"part out the speakers": OH boy, although I know how to use a screwdriver, there are other things for me to pursue at this stage of life. The right person at the right time could possibly benefit form these. Your advice to sell as a package is definitely worth pursuing.

Thank you very much for taking all this time on my project.