JBL C50 SR7 Amp questions

[Megaladoink]

Hello my JBL friends.
I recently purchased a pair of C50 SR7's. In fantastic condition.
Now my question is power. I have (2) Carver TFM-15cb Power Amp and (1) Carver PreAmp CT-17 .

So my questions are:

1) Should I try and bi-amp these beauties?

2) Is this a use-case to use the Bridged feature for the power amp? Bridged gets 300W Mono

3) When do you use bridged?

 

[Nyjblbob]

If you do bi-amp, Yes recommended, you can then bi-pass the Lx5's.
but you will need an adjustable Electronic X-over. with Volume Levels.
there are plenty of old Rane,Ashley, Furman, EV, Crown units for cheap.The carver will be fine on the woofers.
But use something small and sweet for the horns "tubes"? A little 8 wpc or less,
Rebuilt Magnavox
would be perfect.

 

[Megaladoink]

If you do bi-amp, Yes recommended, you can then bi-pass the Lx5's.
but you will need an adjustable Electronic X-over. with Volume Levels.
there are plenty of old Rane,Ashley, Furman, EV, Crown units for cheap.The carver will be fine on the woofers.
But use something small and sweet for the horns "tubes"? A little 8 wpc or less,
Rebuilt Magnavox
would be perfect.

By bypassing the LX5 you mean dont connect to the typical (B) (R) inputs.. connect to the ones labeled (1) LF (2) (3) HF (4) ?

and only connect my carver to the LF. Find another more gentler power amp for the HF connections.. like something 'tube' . Maybe a Mcintosh 225? Or I have a Pioneer SA-9800 laying around. (I am aware these are very different beasts)

Cheers,
Chris

 

[Nyjblbob]

Im not sure you understand real bi-amping. you would just totally disconnect the 4 wires to the xover those go directly to the woofer and horn.
you'll need to make new terminals for the connections.
that horn with 5 watts will be louder than the woofer with 200 watts
You never posted pictures.
Do the Le15 woofers still have the Tan Landsaloy surrounds?
if yes, that is the first thing you have to have done. New Foam surrounds.

 

[Nyjblbob]

Here's the big issue!
Anything you do except for the Re-foam of the woofers, A necessity, would be for your own listening pleasure.
You always have to keep re-sale value in mind. no Mods you do to them will really add any additional value,
except to a flipper or just for the component values

 

[twiiii]

Remember its about quality not quantity. 8 watts is not enough for peaks.

 

[Mr Boochie]

Hello my JBL friends.
I recently purchased a pair of C50 SR7's. In fantastic condition.
Now my question is power. I have (2) Carver TFM-15cb Power Amp and (1) Carver PreAmp CT-17 .

So my questions are:

1) Should I try and bi-amp these beauties?

2) Is this a use-case to use the Bridged feature for the power amp? Bridged gets 300W Mono

3) When do you use bridged?

Did you go down the bi-amp route? You know, I'd prolly fix the crossovers (if needed) and keep the unit OEM, as much as possible. Today, these speakers are so rare to find in good condition. Do your speakers have sculpted grilles?

 

[BMWCCA]

Assuming you meant S7R (not SR7) you have a 2-way system with passive radiators. Easiest way to see if bi-amping does anything for you would be to simply get an Ashly XR1001 (or equivalent) and set it to 500Hz to match JBL's crossover specs. Take the LF output from the Ashly to your biggest amp and run that output directly to your woofer. Take the HF output from the Ashly to a similar or smaller amp and run it directly into your HF horn. Alternately, connect the HF amp outputs directly to the LX5 inputs with the LF disconnected. Adjust levels on either the amps (if there is such) or the Ashly, and see what you think. This way nothing is irreversible in case you either don't like it, find no difference or improvement, or want to sell the speakers. I don't think you can hurt anything by trying. Just don't short the outputs or inadvertently send output from one amp back into the other amp.

 

[Nyjblbob]

Agree except for the setting of 500Hz on the active X-over. With the Lx5's, the 8 ohm Le85's actually raises the x-over point to 700- to 800 hz or so.with a 16 ohm 375 the Lx5 is a 500hz x-over.
That is one of the big problems with that combo. that driver doesn't want to go below 700hz ,
especially with the short horn.,and the Woofer doesn't like to play above 500 cps.

 

[Nyjblbob]

Remember its about quality not quantity. 8 watts is not enough for peaks.

True the heavy cone Le15's like a bit more punch to get them pumping.

 

[BMWCCA]

Agree except for the setting of 500Hz on the active X-over. With the Lx5's, the 8 ohm Le85's actually raises the x-over point to 700- to 800 hz or so.with a 16 ohm 375 the Lx5 is a 500hz x-over.
That is one of the big problems with that combo. that driver doesn't want to go below 700hz ,
especially with the short horn.,and the Woofer doesn't like to play above 500 cps.

So, if you set the electronic crossover to 500Hz for the LF, and then use the HF output to feed the JBL HF through the LX5, would that not accomplish the same thing? Just asking.

 

[Nyjblbob]

Yeah