| LEESTER |
| I have searched different forums to find out how to convert a rack mount equalizer from 110 volt to 12 volt. Can anyone help with a quick explanation? how much work will it be to convert ? |
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| justonemoreamp |
Are these Rane EQ's. I have the pdf file for that. Anybody else it might depend.
Any name brands you have in mind ?
Most all Op-amp based EQ's will need + & - 15 volts to 18 volts depending on the design and chips used.
A really cheap way is to get one of the cleaner 12 to 110 converters, and power it up through a bosch style relay. They handle about 20 to 30 amps and thats is way more power then the EQ's will draw.
Look at the back of the EQ's for the power consumption. It will be in the range of15 to 45 watts at 110 VAC. Thats pretty much nothing.
Other than that your looking a finding DC to DC converters like this one
http://cgi.ebay.com/ws/eBayISAPI.dl...60773&rd=1&rd=1
This is a wide input range DC to DC converter. It works from 9 volts to 18 volts in and delivers + & - 15 volts regulated output possibly with enough current to run one EQ.
I have also seen stacked battery supplies, but ground might have issues with that depending on who made you equipment.
Hope this helps:) |
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| razirafi |
| These are from two Rane equalizers. The one showing the PCB was taken out of its case just to have a look at what's inside.;) |
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| razirafi |
| I don't know if this is the part number... |
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| justonemoreamp |
| quote: | Originally posted by razirafi
I don't know if this is the part number... |
Looks like a modular DC to DC converter to me:) Nice pics THX |
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| pinkmouse |
| You might want to look out for an old Alesis graphic, IIRC, they came with a 12V wall wart. |
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| LEESTER |
Thanks, I spent some time researching this conversion last night with very little success, This is not the first time this forum has helped me out. I bought a cheap samson E62, I'm not sure on the specs, but it's cheap enough that I can experiment on. I want to power it the cleanest way I can. This will be for a SQ car, and I need to hook it up before Spring Break nationals. An EQ was one of the main things I was missing last year, and I just couldn't fork over the cash for a 12 volt equivalent. Please keep an eye on this thread as I intend to update it with some additional pictures once I receive the unit.
thanks |
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| justonemoreamp |
Have you checked out the 31 band Phoenix Gold EQ's on e-bay lately. I saw one go for $85.00 + shipping. These are pretty nice EQ's. I own 4 of them 2 in use, and 2 black face spare. Look for EQ 230 or similar.
They have line drive capability, and seem to be well built, with clip indicators and drive level indicators.
There really isn't much better electronics in most of those other units available after market.:) |
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| LEESTER |
| I've been tracking a few of those eq's as well, I've used Audio Control numerous times, and I was also thinking of using the new 360 from RF. I guess The challenge of something different appealed to me, also the rack equip just looks cool. |
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| justonemoreamp |
Do you remember way back when PPI and Orion had 5 pin DIN plugs on all their EQ's and modules ?
Well inside that DIN cable and plug was + & - 15 volts DC to power all their outboard devices.
Every car amp I see has + & - 15 inside for its op-amp input section. By adding a few turns of wire you could boost its current capacity and then add 3 terminal regulators inside the amps to give you you needed DC power for your EQ's.
But if your not good inside of a amp please have someone that is adept perform these mods, as its not as simply as it looks and sounds, but it is very possible.
Good luck:) |
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| LEESTER |
| quote: | Originally posted by justonemoreamp
Do you remember way back when PPI and Orion had 5 pin DIN plugs on all their EQ's and modules ?
Well inside that DIN cable and plug was + & - 15 volts DC to power all their outboard devices.
Every car amp I see has + & - 15 inside for its op-amp input section. By adding a few turns of wire you could boost its current capacity and then add 3 terminal regulators inside the amps to give you you needed DC power for your EQ's.
But if your not good inside of a amp please have someone that is adept perform these mods, as its not as simply as it looks and sounds, but it is very possible.
Good luck:) |
I'm gonna stay away from modifying my current amps, unless a junk amp can be modified to only be a power source ? Is this is easier than getting a dc-dc converter? I remember the din connectors Alpine used, but they were only signal and remote leads. |
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| djQUAN |
since I have been thinking of doing the same thing for a while now and the thought of running 5 pairs of RCA lines from the front to the back of my car puts me off, I thought about having a look into my 31band EQ........
my unit is a local brand (low cost but nice quality) and I can see a dual mono construction. it contains four boards in all. two holds the main circuitry and two attaches to the front panel containing the slide pots.
it is a dual mono construction and the main board already has on board regulators. it also has two power transformers, one for each channel. the transformers have center tapped outputs so the board accepts two AC terminals and a common making three pins. a SMPS can easily be connected to this, the ground connected to the center tap terminal and +18 and -18 connected on either pins. 18V is needed because of the voltage drop due to the on board regulators. |
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| LEESTER |
| I Recv'd the Eq today, and ripped the top off. I hope these pictures will help to clarify things. Please help tell me what to cut, and what I need. thanks |
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| LEESTER |
| heres another of the exterior |
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| djQUAN |
same as what I saw in mine except mine uses two transformers.
you can connect a +/-18V supply to the connector going to the board from the transformer. the +18 and -18V connected to either red wires (any polarity, +18 to one red and -18 to the other red) and the common connected to the black wire.
you just need to look for a good +/-18V DC-DC converter with around 500mA output current. |
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| djQUAN |
I was able to modify my EQ to be used with 12V.
instead of buying a ready made DC-DC converter, I made a simple fully discrete unregulated SMPS (no need for regulation since the EQ boards already have built in 15V regs.
here's what I took just a few mins back......
a shot of the very simple SMPS:
balanced inputs and outputs! yay!
good enough quality for a little under $100 brand new.
dual mono design. it used to have separate everything except for the power switch and AC input. now I just used a common SMPS for both.
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| Clipped |
over at carsound, they were modding behringer eq's for the car,this was a few years back i think...
but is it even legal to use a non 12volt piece of equipment in IASCA? i havent read the rules concerning this yet. |
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| djQUAN |
| with that modification.....I don't think you can consider my EQ a "non 12 volt" equipment. :) it was but not anymore. :D |
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| djQUAN |
| just want to add the schem that I used for the simple SMPS..... |
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| LEESTER |
| I'm afraid to say, sold my original rack mount eq and got some audio control eqt's, i'm still analogue, and the install went easily. Thanks fo all your previous help, and maybe next time. |
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| richie00boy |
Fantastic Mr Quan :) I'm glad to see that SMPS you did is basically identical to one I'm going to knock up for another project. Did you find any problems/drawbacks with that approach?
Just looking at that rectifier though, are you sure it's drawn correctly? |
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| djQUAN |
ooops. hehehe it's supposed to be a bridge arrangement. :cannotbe:
also, the one I used are schottky rectifiers in two legged TO220's since I already have those in hand.
R1 and R2 adjusts the freq and dead time for the fets.
R3 and R4 set the oscillating freq. with teh values shown, the oscillator runs at 50kHz
since I cannot find the components I used, I substituted ones from the eagle library that should also work.
what I used were: MPSA06 on all small transistors, IRFZ44 fets, and the schottky diodes.
the transformer was an unknown EE core wound with 18+18 turns primary, 28+28 turns secondary.
the supply is powering the amp and has a very small idle current of around 60-70mA without a load and with the entire EQ connected, the idle current is only around 500+mA. there is no heating (except for the onboard regulators of the EQ)
seems to work very well to me. :) |
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| richie00boy |
Did you play with R1 and R2 (560 R) to optimise the dead time? Or just calculate them somehow?
Would you consider a version driving a meatier transformer for maybe an amp? |
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| djQUAN |
nope. I just took what I had on hand and built up the circuit. it does have a little too much dead time though. but still works well without anything heating up.
I'm planning on building a bigger version that can power a car amp but would have to figure out how to incorporate a soft start. other than that, everything else is solved.
planning it to power six channels of P3A, two a little overdriven to get 150x2 and 100x4 |
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| richie00boy |
I'd be very interested to see how you get on.
Do you need soft start? Does the TL and SG chips have soft start? |
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| djQUAN |
the SG chips do have a separete pin just for the purpose, the TL chips can use the deadtime pin for that. my oscillator don't have any. :(
any ideas? I was thinking about powering the oscillator slowly so the SMPS does it in pulse amplitute modulation instead. so the gate voltage ramps up slowly...... |
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| richie00boy |
Yes if the remote pin was ramped it would do that. But it would also cause the MOSFETs to get hot during start up as not fully on, and maybe even not provide all that much soft start action anyway, as the gate voltage is very non-linear.
Ideally you need to start off with shorter pulses of normal amplitude. I think you could do this with a 555 timer, but then you lose the simplicity of the transistor setup. |
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| djQUAN |
well, although it would get hot, it would only be for less than a second so it would be fully on before the sink gets hot.
or if I would use not too much secondary capacitance, I could no longer need soft start. ;) |
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| richie00boy |
I was thinking more in terms of the die temperature rocketing. Although it's probably a minor concern.
I think soft start is needed, you shouldn't have to skimp on capacitance. |
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| djQUAN |
| the last amp I fixed, an orion 225HCCA used PAM for powersupply regulation so I guess that soft start could be accomplished with ramping the gate voltage slowly.....if I increase the soft start delay a bit longer like say 2-3 secs, it might make the fets heat up much slower trather than heat up too quickly at start up. |
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| richie00boy |
Surely if you use PAM, increasing the soft-start period will only make the dies get even hotter? It's probably not an issue though. The other option is to add a traditional resistor/relay soft-start.
Interesting to know that a 'good make' amp used PAM for supply regulation, I really wouldn't expect that of a good design. |
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| djQUAN |
I don't like relays in the main power line. ;) relay on the secondary side? hmmm but that would mean a lot of relays if I include the ones needed for speaker protection.
might as well build it using the schematic and the soft start with PAM. we'll see how it turns out. :)
also, I don't think I would need that much capacitance anyway since it will be driving midbass and up unlike subwoofers which need tons of capacitance. |
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| richie00boy |
| Keep us posted! :) |
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| djQUAN |
| here's where I used my modified EQ. :) took 3 days to complete. |
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| Mike1234 |
| Would this converter work for a Behringer DCX-2496 or DEQ-2496? |
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| N-Channel |
| quote: | Originally posted by djQUAN
nope. I just took what I had on hand and built up the circuit. it does have a little too much dead time though. but still works well without anything heating up.
I'm planning on building a bigger version that can power a car amp but would have to figure out how to incorporate a soft start. other than that, everything else is solved.
planning it to power six channels of P3A, two a little overdriven to get 150x2 and 100x4 |
DJ,
See any of the DC-DC threads either here in the Car Audio forum, or in the Power Supply forum. SG3525 & TL494 are the easiest to implement and have all the functions you're looking for: Softstart, variable deadtime, output sensing, synchronization to an external clock (either slave or master), etc. etc. Plus, they're alot easier to lay out on the pc board than the free-running oscillator is.
Steve |
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| djQUAN |
| quote: | Originally posted by N-Channel
DJ,
See any of the DC-DC threads either here in the Car Audio forum, or in the Power Supply forum. SG3525 & TL494 are the easiest to implement and have all the functions you're looking for: Softstart, variable deadtime, output sensing, synchronization to an external clock (either slave or master), etc. etc. Plus, they're alot easier to lay out on the pc board than the free-running oscillator is.
Steve |
I was trying to do that so I could have a fully discrete amp (no IC's!! :D ) but ended up using TL494 anyway. :smash: |
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