Parasound HCA2200II or HCA3500 safe with SDAs?

Larry Chanin

Hi All,

I'd like to upgrade the Parasound HCA2003 (200w/ch @ 8 ohms) amplifier currently feeding my SDA-1Cs. I have Parasound amps for all my channels (HCA1500As for my side and surround back channels) and I'd like to stick with Parasound.

I was considering buying an HCA2200II (220w/ch @ 8 ohms) or a HCA3500 (350w/ch @ 8 ohms) on the used market, but I'm concerned that they might not have a common ground design that is compatible with SDAs.

The owner's manuals don't say much, but they state that the amps are dual-mono which may present a problem.

HCA2200II:
Dual mono circuit topology for superior separation past 20kHz
(It has one power cord.)

HCA3500:
Each channel of the amplifier has its own power supply including an independent 1.4 kVA toroidal power transformer and 97,600 uF of filter capacitance. This dual-mono configuration provides the high levels of power needed for some of today’s more sophisticated speaker systems. (It has two power cords.)

Does anyone know whether these amps are incompatible with SDAs?

Thanks.

Larry

I-SIG

My HCA-2200 seems to be doing great things with my SDA-1C Studio's. Those Parasounds seem to have a lot of protection schemes. It would seem to me that if there was a problem somewhere one of those protection schemes would have kicked in on my amp by now. I think the Parasound amps are a strong combo with the SDA's. I bet madmax would agree as well.

Wes

Larry Chanin

Hi Wes,

Thanks very much for the response. That certainly relieves me regarding the HCA2200.

I guess what got me wondering was that folks tell you to avoid using mono-blocks with SDAs. I was concerned that the one or both of the subject amps might be dual mono blocks in a single chassis. With two power cords going into the HCA3500 it sure gives that impression.

Thanks again.

Larry

I-SIG

No prob, Larry.

I'm sure someone will correct me if I'm wrong, but I've gotten the impression that most "dual-mono" amps in the same chassis thingies are probably mostly common ground or even standard amps with more seperation or more parallel circuitry.

Wes

dorokusai

Mono-Block and Non-Common Ground amplifiers aren't a problem provided you use the A1-I. SDA's can operate on any kind of amplification.

The HCA-2200 and HCA-3500 are dual mono designs, true enough. The HCA-3500 has no jumper across the power supply legs....while the HCA-2200 does. The HCA-2200 MKII is a John Curl design, and to the best of my knowledge does not have a jumper. Both amplifiers will, for the sake of your speakers, require the A1-I.

I will have a definitive answer tomorrow, on the 2200, as I am not at my house to check my files.

Larry Chanin

Hi Mark,

Thanks for the explanation.

I guess if I go this route it looks like I'd have to build an A1-I since they're no longer sold. I think they have the instructions on the McGowan Brother's SDA web site.

Larry

amulford

Where is the McGowan Bros. website?

Larry Chanin

Hi amulford,

Here's a link to it.

McGowan Bros. Polk/SDA Page

The site is not very active, but there's a lot of good SDA-specific information there. It requires a no-cost registration to access much of the information.

If you're interested in the instructions to making an A1-I, it's if the Files section.
Duh! Now I know why I remember it being on the site... I put it there. :rolleyes:

EDIT: There's also information on the making an A1-I in the Photo Albums section in a folder titled "D.I.Y. AI-1 Interface".

Larry

Larry Chanin

Originally posted by dorokusai
Mono-Block and Non-Common Ground amplifiers aren't a problem provided you use the A1-I. SDA's can operate on any kind of amplification.

Hi Mark,

When I went out to the McGowen SDA web site I found the warning shown on the linked file. Basically it says that some SDA-1Cs need a plug adapter and a crossover modification before they can work with an A1-I. In my case I've got one of the unlucky earlier SDA-1Cs.

INSTRUCTIONS FOR USING THE SDA NON-COMMON GROUND AMPLIFIER INTERFACE


Larry

dorokusai

Yea there is a revision list, it is in the SDA Compendium as well. I think it's just best to make or use the A1-I in every case, that way the user doesn't have to think twice about anything.

PolkWannabie

Awhile back one of the engineers at Polk stated that usage of the A1-I would cause at least a slight reduction of the SDA effect. I don't have that email/post any more but something to at least be aware of ...

dorokusai

Well if anyone can tell me they "hear" that reduction, let me know. I have ran both, and notice zero difference.

F1nut

Ditto

dorokusai

The HCA-3500, HCA-2200 and HCA-2200 MK II are dual mono designs and non-common ground amplifiers.

Larry Chanin

Hi Mark,

Thank very much for the confirmation.

Larry

I-SIG

Originally posted by dorokusai
The HCA-3500, HCA-2200 and HCA-2200 MK II are dual mono designs and non-common ground amplifiers.

Uh-oh. I guess I better get busy making an AI-1.

What signs should I notice of there is a problem?

Wes

dorokusai

When your speakers make a loud shriek, start buzzing and choking like Russman passing out on his back after a Rum bender.

Larry Chanin

Originally I sent an email to Parasound technical support. When I didn't hear from them after a few days I posted here at Club Polk.

This morning they responded and I spoke with Tony Pointes, 415-675-7273.

Tony said that while the power supplies are independent, the output sections have a common ground. He said there should be absolutely no problem.

Well, Wes sorry to stir things up, but if you're not experiencing problems maybe that's the reason.

Larry

dorokusai

Thanks for further clarification. I thought I was pretty exact in my previous email to Tony, but apparently that wasn't the case.

Emlyn

I was concerned about the potential problem with dual mono designs as well when I was looking to get a Rotel RB-1090. Ken responded with this suggestion:

"Hello,
I would believe that there shouldn't be any problems, Rotel has indicated that the left channel ground and the right channel ground are connected, or common. If you wanted to be on the safe side, you could use a Volt/Ohm meter (VOM) set to the lowest resistance setting and place one probe on the left channel's negative terminal and the other probe on the right channel's negative terminal and you should read 0 Ohms. If so, all's well with your SDAs, Rotel is a fine company and they should sound very good.
Regards, Ken"

I tested the Rotel and it read 0 Ohms. Works great too. I've also tested a Parasound A21, which isn't dual mono, but I just wanted to be sure it was common ground before hooking it up to a twin blade connected pair of SDAs.

Larry Chanin

Originally posted by dorokusai
Thanks for further clarification. I thought I was pretty exact in my previous email to Tony, but apparently that wasn't the case.

Hi Mark,

I only spoke to Tony briefly. I merely read to him the warning in the SDA'a owner's manual and asked whether these amplifiers were of a common ground design.

Did Tony happen to respond to you via email? If so, I'd be interested in seeing his response if you still have it.

Thanks very much.

Larry

Larry Chanin

Originally posted by Emlyn
I was concerned about the potential problem with dual mono designs as well when I was looking to get a Rotel RB-1090. Ken responded with this suggestion:

"Hello,
I would believe that there shouldn't be any problems, Rotel has indicated that the left channel ground and the right channel ground are connected, or common. If you wanted to be on the safe side, you could use a Volt/Ohm meter (VOM) set to the lowest resistance setting and place one probe on the left channel's negative terminal and the other probe on the right channel's negative terminal and you should read 0 Ohms. If so, all's well with your SDAs, Rotel is a fine company and they should sound very good.
Regards, Ken"

I tested the Rotel and it read 0 Ohms. Works great too. I've also tested a Parasound A21, which isn't dual mono, but I just wanted to be sure it was common ground before hooking it up to a twin blade connected pair of SDAs.

Hi Emlyn,

That's very helpful information.

Wes: Do you suppose you could give it a try and post your results?

I' rather not buy an amp, test and find out, Opps!

Thanks.

Larry

dorokusai

I spoke with him some time ago, when I first bought my SDA's, and just documented the answers for my file on Word.

Question: Is the Parasound HCA-1500 considered a 'Common Ground Amplifier'? Response: No. I'm sure I could have elaborated further, but I presumed it either is, or is not. This was when I owned that model.

That response alone is what drove me to pick up the A1-I from a Polk member that was building them at that time. Whatever, its all about double checking and re-checking anyways.

I had the same issue, emailed with no response at that time, called them and simply read my email to him. I have contacted them quite a few times over the past 2 years, and they usually are extremely timely in the responses.

Just as a side note, my CTC BBQ, has no continuity between the negative binding posts, in effect Non-Common Ground.

Wes - If it hasn't blown up yet, don't worry about it. Do what Ken suggested, that would be the best idea, and if it's all clear, then crank it up.

Larry Chanin

Originally posted by Larry Chanin

I' rather not buy an amp, test and find out, Opps!

Well, so much for self control. :rolleyes:

This whole thread just moved from the theoretical to the experimental for me.

I just purchased an HCA2200 MK II.

I'll let you know how things go when I receive it.

Larry

DarqueKnight

When making an inquiry to a manufacturer about whether a particular amp is common ground or not, you should also ask if the grounds of the two channels (or the grounds of the two amps, in the case of monoblocks) can be strapped together with a piece of wire if the amp is not a common ground design.

With Adcom's non-common ground amps, all you had to do was connect a piece of heavy gauge wire between the negative negative binding posts. With Adcom's monoblock amps, all you had to do was connect a piece of heavy guage wire between the negative binding posts of the two amps.

dorokusai

I did ask that, and he(Tony) said that they have no experience with modifications on those amplifiers. They consider the strap to be a modification. I am sure that it is possible, I figured it was a no-brainer. I don't stray from manufacturer information unless it's out of warranty.

kelley

Ditto on connecting Denon monos that way

I-SIG

Originally posted by Larry Chanin
Originally I sent an email to Parasound technical support. When I didn't hear from them after a few days I posted here at Club Polk.

This morning they responded and I spoke with Tony Pointes, 415-675-7273.

Tony said that while the power supplies are independent, the output sections have a common ground. He said there should be absolutely no problem.

Well, Wes sorry to stir things up, but if you're not experiencing problems maybe that's the reason.

Larry

Larry,

You da man!!!!

Thanks for the good news. I've been listening to my stupid alarm clock radio all day today.

Time to really crank the SDA's and let 'em rip!!!

Wes

I-SIG

Originally posted by dorokusai
Wes - If it hasn't blown up yet, don't worry about it. Do what Ken suggested, that would be the best idea, and if it's all clear, then crank it up.

I'll borrow a multi-meter form work Monday and check to be safe. I kinda figured I was okay if nothing has happened at this point, but still...

Wes

Larry Chanin

Originally posted by I-SIG
I'll borrow a multi-meter form work Monday and check to be safe. I kinda figured I was okay if nothing has happened at this point, but still...

Wes

Hi Wes,

I sure hope your test on Monday doesn't prove us wrong because that's the day my seller is shipping me my HCA-2200 MK II.

Larry

I-SIG

Here's the scoop on the HCA-2200. When I checked the ohm's across the negative speaker terminals, with SDA cable unhooked of course, I got about the same reading as when simply putting the two leads together. In other words, I got continuity.

Wes