Parasound HCA-3500 common ground??

Phasewolf

I really need a SDA owner to tell me if this amp is common ground before I hook my SDA cable back in. I so want to just plug in the cable but not willing to take a risk when I can just ask.

As for the amp it sounds really nice I will report more later on this once I can really use my speakers.

drumminman

According to a quick search it's a true dual mono design and pics show it has two power cords. I'm guessing it's not common ground. Call Parasound and ask.

You can also check with a multimeter.

Phasewolf

I had a DMM but my friend killed when he set to measure resistances and put the leads into a 440 outlet.

I have seen posts saying it was common ground and that it was not so I am a bit lost on which way it works. I have things to do in a few but when I get back I will dig into this more. I should build the AI-1 and there would be no worries one way or the other but as of now I am broke.

My friend is going to bring his DMM over this weekend as I really need to re-bias the unit one side is hotter then the other which is not uncommon with this unit and it only takes a bit of time to do. Better safe then sorry plus it will sound it's best that way.

drumminman

Phasewolf wrote: »

Better safe then sorry . . . .

^ ^ ^ +1

F1nut

Absolutely not and you can't strap the negative outputs either.

TNHNDYMAN

Damn that's a hell of a nice amp to have and not be able to use on your SDA's. Hopefully you could sell it and recoup your money to apply to an amp that you determine is suitable before purchase. Definitely better safe than sorry, I hate to see the 2.3's destroyed.

Good luck on researching it and finding a workable solution.

Phasewolf

Yes I knew not to strap the neg terminal that can burn up lots of parts. But how about using the AI-1 would that do it for me with this amp?

zingo

AI-1 should work fine if your SDAs are pin-blade.

zane77

Make up a Dreadnought for it, that's what I did for my non-common ground amp

F1nut

But how about using the AI-1 would that do it for me with this amp?

The stock AI-1 or the Dreadnaught will work perfectly with the amp and your SDA SRS 2.3's.

Phasewolf

Well I need to find a good transformer then. What is the 1000VA ones cost I did not need one at the time so I never looked into it.

F1nut

You would have to order 10 of the 1000VA transformers. Your best bet is to order the stocked 800VA version from Avel, item number Y236906. It should run about $130.00 shipped.

You will need an enclosure, so contact Larry (Toolfan66) to see if he has any available. While you're at it, you should upgrade the cable and terminations. I prefer MIT cable and Neutrik connectors.

F1nut

Here's an idea of what can be done, http://www.polkaudio.com/forums/showthread.php?142058-A-slightly-different-take-on-the-Dreadnought&highlight=slightly

Phasewolf

Thanks. I just got a DMM and the reading showed 0 on the display so is seems that it is common ground. So am I good to go? I will build a Dreadnought when I get the cash the amp wiped me and I am hoping to get back to working soon as I can finally feel most of my leg most of the time.

And again thanks a lot for all the help.

F1nut

I don't know how that is possible, it is 2 separate amps in one chassis with 2 separate power cords.

F1nut

Straight from Parasound's site, "Independent power supplies for each channel for true dual-monaural operation."

Phasewolf

And you are correct but looking at the print the amps are tied together on the output at the ground if I am recalling it right. I tried the cable and it was fine.

Phasewolf

Yes the power supply is such the ground for the amps are tied for what ever reason.

F1nut

Hmmmm.....if the grounds are tied together, why 2 power cords and can it really be called a true dual mono design?

Phasewolf

Yes I do get what your saying and maybe I looked at the print wrong but it works fine I played about 20 minutes of music and many levels and no smoke or odd sounds yet... I will report back in a day or so if anything changes or if it dies but I (think) I am in the clear.

Phasewolf

I can not put to words how good this amp sounds with the SDA cable the bass is buttery smooth and completely effortless. The highs are sweet and surreal this is the best amp I have had to date. My wife sat down with me wile I was getting it setup and was playing music and is not longer upset about me spending money or why we had to get yet a other amp and is digging out disks to play on it. It sounds nothing like the sunfire I was running.

This amp is a true beast and about the limit of what I can spend but I really picked a good one. Wile the Onkyo may be not good for a 2 channel music system and a good per would take me so much higher I am in love with how it is sounding they matched up very well and I have no regrets.

F1nut

This amp is a true beast and about the limit of what I can spend but I really picked a good one.

Indeed you did, it is a nice amp and I'm glad you're enjoying it.

Beardog had one, which I heard, but he wasn't using SDA's. Mark has the highly modified BBQ version, which I'm 100% positive is not common ground. Hence, my comment that yours was not either. Must have been one of the things they changed.

While the Onkyo may be not good for a 2 channel music system and a good pre would take me so much higher...

You need a good tube pre amp with an HT bypass

Could be common grounded thru the chassis to equalize bias, lower the noise floor

A common ground isn't needed for the bias and a non-common ground dual mono amp should have a lower noise floor by design.

Schurkey

F1nut wrote: »

Absolutely not and you can't strap the negative outputs either.

Several manufacturers made or make product with a shared ground (common-ground design) and describe their product as "dual mono". Apparently Parasound is one of those manufacturers.

Why do you suspect the negative outputs can't be strapped? Far as I know, the only amp designs that can't have the negatives strapped are those that use a "bridged" or "balanced" design--the negative terminal is in opposite phase and amplitude to the positive terminal, instead of being passive. Am I wrong?

Polkie2009

I've heard about some big power amps needing 2 power cables and that would have made me also question if it was a common ground amp. You are brave Phasewolf, I would have been too afraid to try running that amp to my SRS2's p/b without a Dreadnaught. Looks like you're setup is doing fantastic, enjoy bro!

Phasewolf

Yes it is sounding very good I still need to redo the bias. I know how just have not had the time to as of yet but it's on my list to do.

I also want to install a 30A outlet for my amps but that is still down the road.

FTGV

Schurkey wrote: »

Several manufacturers made or make product with a shared ground (common-ground design) and describe their product as "dual mono". Apparently Parasound is one of those manufacturers.

Why do you suspect the negative outputs can't be strapped? Far as I know, the only amp designs that can't have the negatives strapped are those that use a "bridged" or "balanced" design--the negative terminal is in opposite phase and amplitude to the positive terminal, instead of being passive. Am I wrong?

You are correct on all counts.As long as the negative speaker terminals are at ground potential then strapping is permissable.This is applicable even with mono amps in separate chassis as long as they meet that requirement.According to the schematic the 3500's negative terminals are tied to ground(non bridged/balanced output) so can be strapped.

F1nut

As I noted above, I based my comments on the BBQ version figuring that part of them was the same. Obviously, I was mistaken.

Schurkey

Phasewolf wrote: »

I also want to install a 30A outlet for my amps but that is still down the road.

Don't you mean a pair of 15 amp outlets? A 30-amp outlet is going to need a very strange power cord end, and you're going to need two outlets to permit both amplifier power cables to connect. My reading of the back panel illustrated in the owners manual is that each channel pulls a maximum of 1200 watts, which (far as I know) is easily accommodated with a 15-amp breaker. Two power cords...two 15-amp breakers, two 15 amp outlets are needed. Not one thirty-amp breaker/outlet.

Each of my amps connects to a dedicated outlet attached to a dedicated circuit breaker via 10-gauge in-wall cable. The preamp and source components share another dedicated outlet/circuit breaker.

Phasewolf

I guess I will setup duel dedicated outlets with 20 amp breakers and 10 or 12 gauge and call it a day then.

drumminman

Glad it's workin'out for you. As F1 said, a tube pre with that amp would be an outstanding combination.

F1nut

I guess I will setup duel dedicated outlets with 20 amp breakers and 10 or 12 gauge and call it a day then.

Use 10 gauge and a 30 amp breaker to a single 20 amp rated outlet for the amp and you'll be fine.