1.2 tl's with bi-amp'd Adcom GFA 585's
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Posts: 13
I've had these speakers on and off since new in 1990 and used many different amplifiers. I just hooked up a pair of GFA 585's and I have to say, they've never sounded anything like this. Sound stage is even more pronounced and instruments are all over the place. Just wondering if anyone else has tried this setup? On a side note, I've updated the tweeters to the 198's.
SDA SRS 1.2tl's
Adcom GFA-585's
Adcom GFA-585's
Answers
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Welcome to the forum
Are you using the AI-1 non common ground interface cable?
Show us what you've got there. -
585s are common ground @honestaquarian.
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So using one on each still doesn't pose a problem? Said two in use.
Are they being ran in mono? Running 450 into tweeters makes little sense to me. I'm not following -
Fairly certain they can't be run as mono blocks. Note that description states bi-amped as well.
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Just wait til you update those crossovers. They will have you smiling like the Joker on April Fools Day.The Gear... Carver "Statement" Mono-blocks, Mcintosh C2300 Arcam AVR20, Oppo UDP-203 4K Blu-ray player, Sony XBR70x850B 4k, Polk Audio Legend L800 with height modules, L400 Center Channel Polk audio AB800 "in-wall" surrounds. Marantz MM7025 stereo amp. Simaudio Moon 680d DSD
“When once a Republic is corrupted, there is no possibility of remedying any of the growing evils but by removing the corruption and restoring its lost principles; every other correction is either useless or a new evil.”— Thomas Jefferson -
That's my configuration with two Yamaha M-65's. A little less power, same effect.
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Fairly certain they can't be run as mono blocks. Note that description states bi-amped as well.
My bad i was looking at the 585se
450 8 ohm
600 4 ohm
1000 bridged
I now see plain 585 @ 250 wpc 8 ohm and 400 4 ohm correct does not look like it is bridgable
I stand corrected
Move along -
I still have no idea how two '585s can power 1.2TLs without an isolation transformer in the SDA interconnect cable, unless one amp is powering the midwoofers and the other is powering the tweeters. If that's the case, I'd expect the midwoofer amp is doing all the real work, and the tweeter amp is loafing.
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I still have no idea how two '585s can power 1.2TLs without an isolation transformer in the SDA interconnect cable, unless one amp is powering the midwoofers and the other is powering the tweeters. If that's the case, I'd expect the midwoofer amp is doing all the real work, and the tweeter amp is loafing.
While I tend to agree with @Schurkey, at the same time if the Original poster says it made the speakers come alive for him then who are we to argue?? -
I have one running the tweets and the other the mid-bass. I initially thought the same thing in regards to too much power, but on occasion I like to listen to my music very loud and these can do that. These speakers suck the life out of an amp as you all know. Every so often I would under-drive the tl's with the 555's and get the distortion alert. Doesn't happen with these.
And yes, the tweeter amp is definitely loafing but I really can't tell much difference in the heat output between the two. I'll have to shoot them with my lazer thermometer after a good run and see what that says.SDA SRS 1.2tl's
Adcom GFA-585's -
nooshinjohn wrote: »Just wait til you update those crossovers. They will have you smiling like the Joker on April Fools Day.
I've been looking at the crossovers all over the place. There are alotta options out there. Any suggestions?SDA SRS 1.2tl's
Adcom GFA-585's -
Talk to @VR3 or @westmassguy about that.^^^
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A fellow here by the name of Gimpod makes a nice crossover board if you want to start fresh.
Around 14 years ago, I purchased a pair of SRS2’s from a guy. He was powering them with two GFA-555's.
In the manual, he had written "Adcom GFA-555, one or two." Seems he had been blowing woofers/tweeters out running them with a receiver. Someone at Polk warranty department told him buy one or two of them GFA-555's and you won't have any more problems.Salk SoundScape 8's * Audio Research Reference 3 * Bottlehead Eros Phono * Park's Audio Budgie SUT * Krell KSA-250 * Harmonic Technology Pro 9+ * Signature Series Sonore Music Server w/Deux PS * Roon * Gustard R26 DAC / Singxer SU-6 DDC * Heavy Plinth Lenco L75 Idler Drive * AA MG-1 Linear Air Bearing Arm * AT33PTG/II & Denon 103R * Richard Gray 600S * NHT B-12d subs * GIK Acoustic Treatments * Sennheiser HD650 * -
I have one running the tweets and the other the mid-bass.
The '585 has a single power transformer serving both channels. You'd have more available current supply to the midwoofer drivers if you just used one amp for left channel mid/tweet and one amp for right channel mid/tweet. Of course, you'd need an isolation transformer with this arrangement.And yes, the tweeter amp is definitely loafing
As is, both high-amperage draws (left and right mid-woofers) are pulling on the same power supply, in the amplifier used for the midwoofers.
As long as you're testing, find out what the DC offset is on each channel of both amplifiers.but I really can't tell much difference in the heat output between the two. I'll have to shoot them with my lazer thermometer after a good run and see what that says.
For the record, the "laser" has nothing to do with the temperature-sensing of your infra-red thermometer. It's just a pointing device.
Who's telling you you have "too much power"?I initially thought the same thing in regards to too much power,
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#Schurkey Great information. I have considered running one amp to each speaker but quite frankly haven't spent enough time looking into the transformer. You can never have too much power.
SDA SRS 1.2tl's
Adcom GFA-585's -
Have you heard how your 585's sound in the bridged mode? You may not like their sound as it does change. In my case a single Adcom 555 sounded better than the bridged pair I had on my polks.
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motorstereo wrote: »Have you heard how your 585's sound in the bridged mode? You may not like their sound as it does change. In my case a single Adcom 555 sounded better than the bridged pair I had on my polks.
They are not bridgable from my understanding -
^^^^^Ok then; after a bit of research I see you're correct and they're not bridgeable.
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motorstereo wrote: »^^^^^Ok then; after a bit of research I see you're correct and they're not bridgeable.
the SE versions are -
I have a question, it was posed somewhere else and no one answered. Now I am not going to Bi-Amp (can't anyway) but if you do attach one amp to the top inputs and another to the bottom does this change the impedance load presented to the amp?
Let's say one amp to the mid driver input on both speakers, one amp on the tweeter input on both speakers.Just a dude doing dude-ly things
"Temptation is the manifestation of desire which equals necessity." - Mikey081057
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Shouldn't it all goes through the same crossover.
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Shouldn't it all goes through the same crossover.
I'll accept it haha. I was just curious and never got around to satisfying that curiosity by asking until now. Thanks Ivan!Just a dude doing dude-ly things
"Temptation is the manifestation of desire which equals necessity." - Mikey081057
" I have always had a champange taste with a beer budget" - Rick88
"Just because the thread is getting views don't mean much .. I like a good train wreck doesn't mean i want to be in one..." - pitdogg2
"Those that don't know, don't know that they don't know." - heiney9
"Audiophiles are the male equivalent of cat ladies." - Audiokarma Member -
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The overall "speaker" impedance is a goofy composite of the "Tweeter" impedance and the "mid-woofer impedance".
How the tweeter impedance varies from the midwoofer impedance will affect the impedance presented to the HF vs Mid-and-Low frequency amplifiers.
'Course, it's all frequency-dependent anyway. The impedance presented to the amplifier is a complex interaction of driver and crossover properties as installed in the cabinet, modified by the instantaneous frequencies being reproduced AND with SDA speakers, the instantaneous difference between L and R channels.
Knocking all that down to a single number such as "6-ohm impedance" is a gross simplification. -
SCompRacer wrote: »A fellow here by the name of Gimpod makes a nice crossover board if you want to start fresh.
Around 14 years ago, I purchased a pair of SRS2’s from a guy. He was powering them with two GFA-555's.
In the manual, he had written "Adcom GFA-555, one or two." Seems he had been blowing woofers/tweeters out running them with a receiver. Someone at Polk warranty department told him buy one or two of them GFA-555's and you won't have any more problems.
@westmassguy sells @gimpod crossover boards
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