tri amping a jvc sp-555wd

atnil

Member
2010-09-27 6:03 pm
I'm a newbie and I was thinking if it is possible to tri amp a pair of jvc sp-555wd speaker. Available for me now are a crossover (behringer cx2310) and equalizer (behringer fbq-15020).
Please recommend a mixer and amplifiers (assuming the spkr above is tri ampable) for this home setup.
Can I use car amplifiers? Please help me.
 

atnil

Member
2010-09-27 6:03 pm
Thank you for your reply. The pair of JVC SP-555WD is working. Its specs just in case: 3 way 3 spkr, 125w power handling cap, 210w music, 35hz- 20khz, 8ohms, 12" woofer, 10 cm mid. I want to triamp this pair of speaker because I can't find a reasonable price of speaker that are triampable ready (like QSC digital cinema series). Besides, I want to try triamping an old speaker before doing that to a more expensive pair.
Could you please show me how to do the tri amping on this pair of speaker?

"You can use car amps but you will need a 13.8 V (nominal 12V) supply that can give you a huge amount of Amperes, ................. and that will be expensive."

I was thinking of a regulated power supply to supply power to 3 car amps. The current rating of power supply will depend on the 3 amps rating. If this is not possible, I'll be using a power amp that will be recommended here in forum.
 
What are the current crossover points and what sort of slope is used?

I used PCBs from Elliott Sound Products; active crossover P09 and P19 amps. Read the articles on the website.

3 car amps per speaker at, say, 20 Watts each (on the low side if you like rock) equals 60 Watts. 60 divided by 12 equals 5 Amps at a minimum. And you will need two of them.


Frank
 

atnil

Member
2010-09-27 6:03 pm
"What are the current crossover points and what sort of slope is used?"

A: Sorry I have no idea. I have no manual for this speaker. I know there's a passive crossover inside the speaker. The tweeter is 4 ohms and 8 ohms for Mid and Low.

"I used PCBs from Elliott Sound Products; active crossover P09 and P19 amps. Read the articles on the website."

A: Do I need to make a active crossover P09? ( Available for me now is a
an active crossover behringer cx2310). The P19 amp from Elliott Sound Products states "It could also be used as a midrange and/or tweeter amp in a tri-amped system". Does it mean I need 3 pcs of P19 amp? Is it sufficient to drive the Bass/Low?

"3 car amps per speaker at, say, 20 Watts each (on the low side if you like rock) equals 60 Watts. 60 divided by 12 equals 5 Amps at a minimum. And you will need two of them."

A: To clarify, I need two power supply? Can I just use one? Shouldn't the power supply Amperage rating equals SQRT of (Power/Resistance)?

Thank you for the reply.
 

atnil

Member
2010-09-27 6:03 pm
Frank,

This is the only info I can obtain from this vintage speaker:
External: JVC SP-555W 3 way 3 spkr, 125w power handling cap, 210w music, 35hz- 20khz, 8ohms
Internal: (1) 4 ohms Tweeter, (1) 8 ohms Midrange and (1) 8 ohms Bass
No manual can be obtain for this speaker.

If this speaker can't be tri amp because of missing information, is there a speaker that can be DIY to suit for tri amping? Anyone tried to do tri amping already?
 

sounddoc

Member
2007-04-16 12:25 pm
Sydney
A pair of multi-channel car amplifiers should provide all the channels you need to drive 6 speakers but powering them is a problem. Maybe you could power them from an automobile battery and keep it charged with a small battery charger that maintains a trickle charge to the cells.

Many of these multi-channel amps have built in crossovers that are adjustable in frequency, but they are designed for sub-woofers so the x-over frequency may not extend high enough for your particular speakers.

What you need to do is get someone with technical skills that can help you uncouple individual amplifiers inside each car amp and extend them out on seperate cables (probably with RCA plugs) that will connect to your electronic x-over outputs.

Because the speaker data is unknown you'll have to experiment a little, just like the rest of us, and do some research! (Google is your friend)

Here is a link to a magazine article that I just turned up by spending 10 minutes searching.
Active 3-Way Crossover (Silicon Chip, January 2003)
Silicon Chip Online - Active 3-Way Crossover for Loud Speaker Systems

It is a 3way Crossover project with adjustable x-over points, with a tuning table at the end of the article. Read it carefully and you should find a few answers to your questions. Let us know how you go.

Sound Dr :cool:
(from Down Under)
 

atnil

Member
2010-09-27 6:03 pm
Frank, Sound Dr... thanks for sharing your time.

I have been thinking two ways to do the tri amping on this speaker. (Correct me please if I'm wrong)
First, Mixer--> Equalizer-->Active Xover-->P19-->Hi
-->P3A-->Mid
-->P3A-->Low

Second, Mixer--> Equalizer-->Active Xover-->Car amp1-->Hi
-->Car amp2-->Mid
-->Car amp3-->Low
Note: P19,P3A from Elliott Sound Products
I have already a Mixer,Equalizer and Active Xover
Car amp will be powered by Regulated power supply
All setup will be use for home only

Questions:
If I connect the P19 amp to the tweeter, do I need to have a 25uF cap in series with the tweeter? Is the 25uF sufficient? I guess The P3A will be directly connected to the Mid as well as the Low.

If car amp1 is 25w stereo and will be driving a two 4 ohms tweeter, then the current will be 5A. Am I right?
If car amp2 is 50w stereo and will be driving a two 8 ohms Midrange, then the current will be 5A. Likewise for the Bass
So, the Regulated power supply will be be rated 20A (5A allowance) and 12V. Again, please correct me if I'm wrong.
 
If this speaker can't be tri amp because of missing information, is there a speaker that can be DIY to suit for tri amping? Anyone tried to do tri amping already?
I have tri-amped my speakers;
Bass Peerless 830868 8"
Mid Peerless 832873 5"
Tweeter Vifa D25 1"
And they work a treat.

Regarding the cat amps, I suppose you could but why would you when you would need a battery and charger or a high Amp 12V supply? I would (have) opt for the mains supply and use one large toroidal transformer.

Questions:
If I connect the P19 amp to the tweeter, do I need to have a 25uF cap in series with the tweeter? Is the 25uF sufficient? I guess The P3A will be directly connected to the Mid as well as the Low.

If car amp1 is 25w stereo and will be driving a two 4 ohms tweeter, then the current will be 5A. Am I right?
If car amp2 is 50w stereo and will be driving a two 8 ohms Midrange, then the current will be 5A. Likewise for the Bass
So, the Regulated power supply will be be rated 20A (5A allowance) and 12V. Again, please correct me if I'm wrong.
Yes, Yes and yes but with a speaker protector in circuit.
I don't follow the second paragraph.

Frank
 

atnil

Member
2010-09-27 6:03 pm
Frank, Sound Dr:

Sound Dr,
Thank you for the link you provided: Silicon chip online


Frank,
It's good to hear you have a triamped system. It must have nice listening to the sound of it. I never thought it can actually be done.
Now, I'm ordering the pcb from esp and build the P19 and P3A amps.

Q1: Is it possible to build one P19 and two P3A amps in a single enclosure? Each amp has its own power supply or just one power supply? OR Does it have to be separate enclosure and power supply for each amp?
How about installing the three amps in/out of the speaker box? (impossible I guess)

Q2: About your tri amped speaker, did you design and build them yourself? Do you know if there 's a kit for a tri ampable speaker? If there's no kit, will you please share your knowledge in building/DIY the speaker? A detailed drawing of the speaker box maybe?


Thank you.
 

atnil

Member
2010-09-27 6:03 pm
Frank,

The second paragraph: (I'm trying to calculate the voltage and current rating of the planned regulated power supply) Following the formula of current= square root of (power/resistance)

"If car amp1 is 25w stereo and will be driving a two 4 ohms tweeter, then the current will be 5A. Am I right?
If car amp2 is 50w stereo and will be driving a two 8 ohms Midrange, then the current will be 5A. Likewise for the Bass
So, the Regulated power supply will be be rated 20A (5A allowance) and 12V. Again, please correct me if I'm wrong."

I'm thinking of a diy power supply that use a torroidal transformer to power the three car amps mentioned above. 12V, 20A power supply maybe?

Also, please see attached image (pasetup4.gif) for my inspiration (dream).
 

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atnil

Member
2010-09-27 6:03 pm
Frank,
It's good to hear you have a triamped system. It must have been nice listening to the sound of it. I never thought it can actually be done.
Now, I'm ordering the pcb from esp and build the P19 and P3A amps.

Q1: Is it possible to build one P19 and two P3A amps in a single enclosure? Each amp has its own power supply or just one power supply? OR Does it have to be separate enclosure and power supply for each amp?
How about installing the three amps in/out of the speaker box? (impossible I guess)

Q2: About your tri amped speaker, did you design and build them yourself? Do you know if there 's a kit for a tri ampable speaker? If there's no kit, will you please share your knowledge in building/DIY the speaker? A link or a detailed drawing of the speaker box maybe?
Or can you please point me to where can I buy already made tri ampable ready speaker?

Thank you.
 
atnil,
I am very happy with my speakers. It can be done and has been many times, such as this, Bi-amping and Tri-amping: Why and How and on Rod Elliott's web site.
My amps and crossovers are built into the base of the speakers and are fed by a balanced input, using XLR connectors, from my pre-amp.
I used one power supply and I really doubt that separate supplies are worth it and are certainly not cost effective.
Either in or out of the box is possible and practical, you really need to think it through first and do many 'doodlings' on paper to see how it will look - lots of measuring too.

My speaker started out as a two-way published in a 1985 now defunct Australian magazine, Australian Electronics Monthly. I did, initially, bi-amp a two way last year, doing one speaker first, and was able to compare them. The passive crossover sounded as if it had a towel draped over the front over it in comparison to the active speaker.

Heartened by the improvement, I added a mid range driver and tri-amped the original passive. It, too, was an improvement so I now have tri-amped speakers. I should point out that this whole exercise started as a result of me setting fire (literally) to my amp while a drunken night with friends listening to the Rolling Stones. The amp took out one bass driver and the rest is now history, as they say.

I had the drivers already (I replaced the burnt bass drivers -both boxes with a Peerless comparable) so I didn't actually have to plan that aspect. You have the JVCs so I would use them. You have a variable crossover, don't be afraid to experiment. Just make sure you don't turn up the volume until they are ready. :)

One thing I do suggest to anyone wishing to go this way is ensure you use good quality drivers that have a wide frequency range so that the driver roll-off is not a factor you need to take into account. Let the crossover do that for you.


Frank
 

atnil

Member
2010-09-27 6:03 pm
Frank,
Thank you very much for all the info you shared. I have a lot of learning to do.
Right now, I'll be concentrating on getting the esp boards and building the amps. Hopefully everything will be smooth during the construction and testing.
Again, thank you for spending time with a newbie.