Aragon Amps with SDA speakers

bugsnt

Hi All,

New SDA owner here... I want to use either one of my Aragon amps 8008BB or 8008x3 to power my SDA-2Bs.
I am aware of the need for common ground on the amplifier end.

From my reading here...

Do I need to take a measurement between the the two negative binding posts 1st?

Can I simply connect a wire between the two negative posts on my 8008BB?

With the 8008x3 amplifier ... do I connect all 3 negative posts?

I want to ensure that I don't damage either the amps or speakers before I go any further.

Thanks for any input.

zane77

Use an ohm meter and measure the resistance between the negative post of the two channels you want to use for your SDA's. It should read very close to zero ohms. If it does you are safe to use the amps. Or you can contact Aragon and ask them if they are common ground or maybe someone with some experience with these will chime in.

DaveHo

Take a look at this article from Indy Audio Labs(new owner of Aragon & Acurus): http://www.indyaudiolabs.com/blog/2013/4/11/common-ground-amplifier-designs ,3rd & 4th paragraphs

zane77

Looks like you will need a Dreadnaught or AI-1 interface for this amp

Schurkey

You can go ahead and measure resistance, but I've measured three 8008BBs, and they're all ~20 ohms between the channels on the negative terminals. They are semi-common-ground, or partial-common-ground, and they sound like **** with my 1Bs. I have every expectation that the 8008X3 is the same.

Another member here has an 8008BB, and it actually shut down when used with his 3.1TL. (I think they were 3.1TLs.)

A simple jumper wire between the negative binding posts of the two channels is all it took to instantly and completely fix the problem for me. The other member also tried a jumper wire, but ultimately preferred the Dreadnaught isolation transformer. The isolation transformer is not an option with my 1Bs. It is for your 2Bs. If you use the 8008x3, you'd jumper the two channels that drive your 2Bs. There's no need to jumper the third channel. If you choose to use the isolation transformer, you don't need the jumper wire.

http://www.polkaudio.com/forums/showthread.php?74472-The-AI-1-Dreadnought-Project-Pt.1

The link above is the best start. There are many other threads but that's the one to begin with. Search for "Dreadnought" (proper spelling) and also "Dreadnaught" (commonly used spelling) on this site.

For the record, Indy Audio Labs does not recommend the jumper-wire solution; but wouldn't tell me why except that it was "safety" related. I discount their concern, as I've been using the jumper wire for years without problem.

FTGV

Schurkey wrote: »

For the record, Indy Audio Labs does not recommend the jumper-wire solution; but wouldn't tell me why except that it was "safety" related. I discount their concern, as I've been using the jumper wire for years without problem.

Likely because the purpose of the two 10ohm resistors is to tie each channels circuit ground to chassis "safety' ground separately.The resistance eliminates the potential for ground loops that could occur if there was a direct connection to the chassis.However jumpering the negative terminals does not negate the chassis connection ,it just changes the resistance due to them now being connected in parallel.

Polkie2009

Schurkey wrote: »

You can go ahead and measure resistance, but I've measured three 8008BBs, and they're all ~20 ohms between the channels on the negative terminals. They are semi-common-ground, or partial-common-ground, and they sound like **** with my 1Bs. I have every expectation that the 8008X3 is the same.

Another member here has an 8008BB, and it actually shut down when used with his 3.1TL. (I think they were 3.1TLs.)

A simple jumper wire between the negative binding posts of the two channels is all it took to instantly and completely fix the problem for me. The other member also tried a jumper wire, but ultimately preferred the Dreadnaught isolation transformer. The isolation transformer is not an option with my 1Bs. It is for your 2Bs. If you use the 8008x3, you'd jumper the two channels that drive your 2Bs. There's no need to jumper the third channel. If you choose to use the isolation transformer, you don't need the jumper wire.

http://www.polkaudio.com/forums/showthread.php?74472-The-AI-1-Dreadnought-Project-Pt.1

The link above is the best start. There are many other threads but that's the one to begin with. Search for "Dreadnought" (proper spelling) and also "Dreadnaught" (commonly used spelling) on this site.

For the record, Indy Audio Labs does not recommend the jumper-wire solution; but wouldn't tell me why except that it was "safety" related. I discount their concern, as I've been using the jumper wire for years without problem.

Great info here Schurkey, I've seen you post about the Aragon 8008bb before using it with SDA speakers. Years ago I was wanting to get a 8008bb to run my SDA/SRS 2's but realized I couldn't do that without some type of modification. (At the time IndyLabs wrote to me about the 20 ohm difference, they wouldn't tell me it would be ok to strap the negative posts) I eventually gave up trying to find a used 8008bb settled for a used Parasound 1200 II( still runs great!) I bought from one of our awesome polksters here. Maybe someday I'll try finding a good used Aragon 8008bb, a lot of people said they sounded fantastic.

drumminman

The Dreadnought is the way to go. I've built one with both the Avel-Lindberg 800VA toroid and 1000VA. The latter was audibly better, but the smaller was no slouch. Both produced improvements with my common ground amp.

You can build the smaller one, including enclosure and binding posts for around $200 - $225.

Schurkey

Polkie2009 wrote: »

Maybe someday I'll try finding a good used Aragon 8008bb, a lot of people said they sounded fantastic.

There's two 8008x3 amps on Audiogon right now. The first one started out at $1150, and is now down to $1000; it's been for sale for a long time. The second one--and there are two ads for the same unit--has been listed about a week at $850. $850 is a pretty fair price. I bought my 8008BBs for about that same price, but that was back in 2005 or so. Used Aragon amps are increasing in price. Even the Acurus-based "Aragon" amps of the Klipsch generation seem to be increasing; as are the Mondial Acurus and Aragon prices. Everything except the Home Theater processors seems to be going up. A Stage One processor is an outright BARGAIN right now--a FIRST-CLASS, THX-certified processor selling for below the price of brand-new Chinese junk. (If you can live without 96-24 decoding, and the very latest movie-decoding formats.)

The 8008x3 uses the same amp circuit--including the full 12 output transistor per channel set--as the BB. There are significant differences in the power supply, case styling, and the 'x3 doesn't have the XLR (balanced) input sockets that the BB has.

Polkie2009

oops

Polkie2009

That case design on the 8008BB is a solid sender, plus you have to love the balanced inputs. You got ya' a good deal on yours Schurkey!

Schurkey

Polkie2009 wrote: »

That case design on the 8008BB is a solid sender, plus you have to love the balanced inputs. You got ya' a good deal on yours Schurkey!

Got a better deal on the Palladium IIs, and it just kills me that I can't use 'em with the SDA 1Bs.

bugsnt

Thanks for all the input and advice.
I had emailed Indy Labs but I never got a response back regarding my questions.

Funds are a bit limited right now so the Dreadnought option will not be an option right now.

Guess I can try to strap the two negative posts on the 8008BB and give it a try.

Schurkey

bugsnt wrote: »

Thanks for all the input and advice.
I had emailed Indy Labs but I never got a response back regarding my questions.

Funds are a bit limited right now so the Dreadnought option will not be an option right now.

Guess I can try to strap the two negative posts on the 8008BB and give it a try.

The jumper has been working for me for years. Don't worry. You'll be fine. You're gonna LOVE how that 8008BB (or the 8008x3) works with your SDA 2Bs. The Aragons are so...effortless.

bugsnt

@Schurkey

I bought my 8008BB and 8008x3 way back when Mondial was the owners and have loved both amps ever since.

I'm running into the RCA inputs only on my 8008BB, Do I need to do anything to the XLR inputs?
Any advice?

Thanks much... I'm so looking forward to this weekend.

Schurkey

bugsnt wrote: »

I'm running into the RCA inputs only on my 8008BB, Do I need to do anything to the XLR inputs?

Nothing you aren't doing already (I suspect.)

The XLR inputs require a shorting bar between two of the three sockets in each connector. The amps come with these bars installed. By "bars", I mean a short, U-shaped piece of solid-core copper wire that poke into the individual pin sockets.

I forget for the moment which two pins need to be jumpered...but...I have every expectation that you've already got these jumpers in place in the XLR connectors.

One of my used amps came to me without these bars. I suppose the previous owner used the XLR connectors instead of the RCA connectors. I made replacements from the ground wire in a piece of scrap household electrical wiring. Might have been 14 gauge "Romex", and probably less-than-one-inch pieces bent to fit.

headrott

Sorry, I didn't see this thread until now.

I used to own an Aragon 8008bb made by Mondial (I sold it though). Schurkey is correct. the 8008bb would go into protection mode over and over with my 3.1TL's without using an AI-1. You will need an AI-1 to use the 8008bb with your 2B's (assuming your 2B's can use the AI-1, which most likely they can (if they have the pin/blade connection, definately they can).

Also, with your 8008bb when using the RCA inputs, you need the jumpers (as brought up before, I believe) in between pins 1 and 3 of each XLR jack. It is required for proper functon.

I hope this helps.

Edit: You can also "strap" the grounds on the binding posts, but it reduces the audio quality. I highly recommend the AI-1 instead.

Schurkey

headrott wrote: »

You will need an AI-1 to use the 8008bb with your 2B's (assuming your 2B's can use the AI-1, which most likely they can (if they have the pin/blade connection, definately they can).

ALL 2Bs can use the AI-1, early production speakers will require an ultra-simple and inexpensive modification.

headrott wrote: »

You can also "strap" the grounds on the binding posts, but it reduces the audio quality. I highly recommend the AI-1 instead.

Several folks have said this. I have some amount of difficulty believing it; but I can't test for myself because my speakers are incompatible with the AI-1.

One wonders how an AI-1 compares to a single conductor of equivalent or larger gauge size (Let's say 14- or 12-gauge) run between the negative terminals of the SPEAKER instead of the negative terminals of the amplifier. Connecting at the speaker would require a much longer wire than at the amplifier, but removes the lengths of speaker wire from that part of the circuit--in other words, common-grounding directly at the speaker may actually be more "direct" than common-grounding at the amp. This is something I CAN try, and probably will in the next week or so.

TennMan

Schurkey wrote: »

...
One wonders how an AI-1 compares to a single conductor of equivalent or larger gauge size (Let's say 14- or 12-gauge) run between the negative terminals of the SPEAKER instead of the negative terminals of the amplifier.

I was under the impression that the AI-1 was an isolation transformer. If so I don't believe a length of wire would be an equivalent to it, or a replacement for it, no matter what gauge wire you use.

pitdogg2

Schurkey wrote: »

One wonders how an AI-1 compares to a single conductor of equivalent or larger gauge size (Let's say 14- or 12-gauge) run between the negative terminals of the SPEAKER instead of the negative terminals of the amplifier. Connecting at the speaker would require a much longer wire than at the amplifier, but removes the lengths of speaker wire from that part of the circuit--in other words, common-grounding directly at the speaker may actually be more "direct" than common-grounding at the amp. This is something I CAN try, and probably will in the next week or so.

Why would this not be considered a direct short? It would still not have the needed ground at the amp?

bugsnt

MORE MYSTERY now...
I was originally told by the seller that the SDAs were early SDA-2B... BUT I have not confirmed it yet.

Would the situation change any if my speakers were SDA-2A?
I understand that the AI-1 and Dreadnought might not be an option for SDA-2A?
Can I still strap the neg posts on my Aragon for SDA-2A?

Thanks again.

pitdogg2

bugsnt wrote: »

MORE MYSTERY now...
I was originally told by the seller that the SDAs were early SDA-2B... BUT I have not confirmed it yet.

Would the situation change any if my speakers were SDA-2A?
I understand that the AI-1 and Dreadnought might not be an option for SDA-2A?
Can I still strap the neg posts on my Aragon for SDA-2A?

Thanks again.

Nope SDA2a are a harder speaker to drive There is no A1 for Blade/Blade interconnect as BOTH large and small blades carry signal. SDA2a are 4ohm and dip lower into 3 possibly lower.

Yes the situation would change and not for the better....

Schurkey

TennMan wrote: »

I was under the impression that the AI-1 was an isolation transformer. If so I don't believe a length of wire would be an equivalent to it, or a replacement for it, no matter what gauge wire you use.

pitdogg2 wrote: »

Why would this not be considered a direct short? It would still not have the needed ground at the amp?

A longer jumper wire between the negative terminals of the speakers accomplishes EXACTLY the same thing as a jumper wire at the negative terminals of the amplifier. It is a dead short BETWEEN THE CHANNELS on the GROUND side of the circuit. Therefore, it must be used with amplifiers like the Aragon which are already "mostly" common ground except for some small amount of resistance between the channels on the negative side. It is NOT a substitute for an AI-1 when using any bridged or otherwise fully-non-common-ground amps like the "inverted-channel" Carver amps.

My comments are in relation to those who say the AI-1/Dreadnought "sounds better" than a foot of plain wire of suitable guage at the back of the amp. I'm wondering if the difference is the inclusion of the full length of speaker cable in the SDA circuit versus providing a common ground directly at the speaker terminals.

bugsnt wrote: »

MORE MYSTERY now...
I was originally told by the seller that the SDAs were early SDA-2B... BUT I have not confirmed it yet.

Would the situation change any if my speakers were SDA-2A?
I understand that the AI-1 and Dreadnought might not be an option for SDA-2A?
Can I still strap the neg posts on my Aragon for SDA-2A?

pitdogg2 wrote: »

Nope SDA2a are a harder speaker to drive There is no A1 for Blade/Blade interconnect as BOTH large and small blades carry signal. SDA2a are 4ohm and dip lower into 3 possibly lower.

Yes the situation would change and not for the better....

The 2A may require more current from your amplifier, but a true Aragon amplifier like your 8008BB or 8008x3 will wet it's pants with laughter at the thought that a 3-ohm load is "difficult" for it. The Aragon amps are known to drive one-ohm loads. My 1Bs were a nominal 4-ohm load before I replaced the SDA inductors with iron-core units having less DC resistance, they're surely 3-ohm (or less!) speakers now.

With 2As, you will need the jumper wire, either between the amplifier negative terminals or between the speaker negative terminals. As said, the 2As aren't compatible with the AI-1 or Dreadnought version of the AI-1, so it's not a matter of whether you "can" strap the negative posts, that jumper wire is the only solution, and an absolute requirement.

Remember that early 2Bs will have the blade/blade interconnect sockets, but a minor modification to the speakers makes them fully AI-1/Dreadnought compatible.

headrott

I will just say that when I was refering to the 2B's, I was assuming no alterations to them by the OP.
That said, it becomes a totally different story if they are 2A's and this has been addressed already.

Last, I have heard the differences between the AI-1 and strapping the negatives on the Aragon. I have done both and I know that the AI-1 sounds better.

Polkie2009

headrott wrote: »

I will just say that when I was refering to the 2B's, I was assuming no alterations to them by the OP.
That said, it becomes a totally different story if they are 2A's and this has been addressed already.

Last, I have heard the differences between the AI-1 and strapping the negatives on the Aragon. I have done both and I know that the AI-1 sounds better.

For what it's worth, I've read numerous times where folks have used the AI-1 instead of their interconnect cable (p/b) with a common ground amp and found it to sound better.