Did JBL factor ESR values in when designing networks???

[kelossus]

Got my hands on a PT800/PS1400 stack and looking at the networks all the capacitors are Elytone branded electrolytics.

The tinkerer in me wants to upgrade them all to modern film caps as they are close to 15 years old now. Since every capacitor is a NPE did Greg Timbers/JBL voice the networks with their ESR in mind? Or do the Elytone NPE's have a low enough ESR swapping them for a film cap wouldn't be an issue ESR-wise.

[Ian Mackenzie]

Can you post the schematic?

Typically they bypass non polarised capacitors in the mid and Hf filters with small value polypropylene caps.

If they are not bypassed you could try that as a first option. If your budget will cover it use film caps in the mids and highs and Change couple with Solen Fast capacitors gives a good result

Non polarised capacitors usual have a low esr at low frequencies with large values so they are okay for low crossover points > 300 hertz. People have lots of opinions on the subject mind you and l prefer to Biamp removing the L (inductor).

[kelossus]

Can you post the schematic?

Typically they bypass non polarised capacitors in the mid and Hf filters with small value polypropylene caps.

If they are not bypassed you could try that as a first option. If your budget will cover it use film caps in the mids and highs and Change couple with Solen Fast capacitors gives a good result

Non polarised capacitors usual have a low esr at low frequencies with large values so they are okay for low crossover points > 300 hertz. People have lots of opinions on the subject mind you and l prefer to Biamp removing the L (inductor).

Hi Mate

All the capacitors are bypassed by poly caps. The schematic at the bottom is the HPF used when docking the PT800 on to the PS1400.

82601

[Ian Mackenzie]

Okay,

The next level up is to try film caps in place of the non polarised electro / film bypass caps.
There are numerous brands available. Here for example: https://speakerbug.com.au/index.php?route=product/category&path=25

Following that a more expensive but revered option is charge couple capacitors. This is basically two capacitors in series of double the original value. The centre noted is biased with a dc voltage via a very high resistance like 2.2 Mega ohms. There is numerous examples of this in schematics of the K series JBL systems.

There is one important cost benefit caveat here. Your associated audio components need to be of a uniform quality to any improvements. Otherwise any improvement in transparency in the crossover will illuminate the artefacts like noise, distortion and colourations from those components. Separates nearly always perform better than a wonder box. For example a 20 year old HT receiver won't cut it. But if you have a 20 year old Bryson pre power combination or of that order of quality it would be worth while.

[kelossus]

Thanks Ian

I have a pretty decent Vitus RI-100 Integrated Amplifier. The PS1400 plate amps are cactus and I use an Crown XLS2500 in there place.

Have had charge coupled 250TI's and L212's in the past. Unsure if I will keep these speakers but between them and the 250TI's its hard to pick the better system. Both do things very well and very different from another.

If I were to change the Electro's to Film caps would I have to measure the original ESR of the electrolytics and match them with a series resistor? Or is this not really necessary.

[kelossus]

I have swapped out all the Electro's beside the very large 300uf in the HPF section. Replaced them all with a combination of the Jantzen Cross-Cap and Standard Cap. Also the bypass cap's have been replaced also.

The speakers soundstage has collapsed significantly. Unsure if this is due to the capacitors being brand new or the ESR being thrown out but something sounds off.

[Ian Mackenzie]

Thanks Ian

I have a pretty decent Vitus RI-100 Integrated Amplifier. The PS1400 plate amps are cactus and I use an Crown XLS2500 in there place.

Have had charge coupled 250TI's and L212's in the past. Unsure if I will keep these speakers but between them and the 250TI's its hard to pick the better system. Both do things very well and very different from another.

If I were to change the Electro's to Film caps would I have to measure the original ESR of the electrolytics and match them with a series resistor? Or is this not really necessary.

No. The actual capacitors tolerance value is worth checking.

[Ian Mackenzie]

I have swapped out all the Electro's beside the very large 300uf in the HPF section. Replaced them all with a combination of the Jantzen Cross-Cap and Standard Cap. Also the bypass cap's have been replaced also.

The speakers soundstage has collapsed significantly. Unsure if this is due to the capacitors being brand new or the ESR being thrown out but something sounds off.

Check the values of the replacement caps and your wiring

Its easy to get things mixed up.

Also check the polarity of the drivers with a 1.5 V battery at the amp end of your speaker cables.

Again I have mixed things up on numerous occasions then modifying crossovers.

[Ian Mackenzie]

Thanks Ian

I have a pretty decent Vitus RI-100 Integrated Amplifier.

With that amp what are you doing on these forums...LOL?