View Full Version : Hafler XL280 or Adcom GFA-585LE for L100T

05-02-2009, 02:44 PM
hey ya all, new board member here...

I'm the original owner of a pair of L100T's I got back in 1990 or so. I'm finally getting the 2214H woofers refoamed after many years of neglect... My stack is an Adcom gfp565 preamp, Adcom 555-II tuner, an inexpensive Yamaha CD player, a Denon quartz/beltdrive turntable, and I have both of the above amps...

the GFA-585 is a real beast. it dims the lights in the room when I switch it on. I believe its rated at 250W RMS DC to daylight, but only if you put it on a dedicated 15 amp A/C circuit :blink: Its also a real monster to lever up onto my amp shelf which is at the very top of a narrow 'closet' built into the living room wall, I think it weighs like 80 lbs.

i've always liked the xl280, its just a sweet amp, never given me any grief, and its whats up on my amp shelf right now... I think it was rated at 140W RMS dc to daylight per channel, but we pulled something like 200 watt RMS sine waves out of it on my friend bench with a dummy load (a 8 ohm heater element) and a signal generator input and it just got warm (we put fans on the heatsinks)...

I listen to a wide range of music, from acoustic modern folk music to bebop & free jazz to loud rock of the SRV variety, and even occasionally Reggae or somekinds of modern rock. Got a big house, and when the girls are gone, sometimes I like to crank it up, hard.

so... whats the consensus? stick with my XL280, or lever that adcom back up in its place? The adcom probably has 3dB more headroom than the Hafler, but at the expense of dimming the lights :rockon1:
at 91dB/watt, I'm not sure the L100T's need that kind of power :)

05-09-2009, 03:03 PM

so, no-one is going to discuss the relative merits of using one or the other of my two amps for my L100T's? I'm shocked, I tell you, shocked! :banghead:

(j/k! but I'd still love to hear from the cognoscenti aboard this good ship Lansing...)

05-09-2009, 04:09 PM
OK, I'll bite. I missed the post first time around and normally don't visit here.

I've had Hafler gear almost continually since the 80s, when I first purchased a preamp and amp in kit form. They were fun and lasted many years. These were popular amps to mod back then with many, many POOGE articles written in the publications know known as AudioXpress. See them for back copies if you're interested.

Currently, I use a Hafler P500 (pro version of the DH-500) and a DH-220 (similar to your Xl-280). All of them have the Musical Concepts driver boards and upgraded power supplied. If you like the XL-280, then you'll _love_ these upgrades.

The problem, here, is that I'll never get any return on investment for the cost of the upgrades, which of course I did myself. Still, sonically, there's quite a performance bump up in their use.

One other thing to consider on the Haflers is that the output devices are pretty well No Longer Available so treat it well.

I've never had Adcom gear but perceive them to be of similar build and design as the original Haflers.

All the above, to say that I'm a confirmed Hafler guy with the predisposition to them.

Frankly, given the speakers involved, you're likely to have some internal bleeding if you drive them hard with either amp.



05-09-2009, 04:53 PM
Sounds like you're sold on the adcom, get better lights!

05-09-2009, 05:05 PM
Oh yeah, for about the dimming lights.....

If you've got lights dimming with a single 250wpc amp, there are other problems outside of the system itself. Deal with those first before moving on to amp decisions.



05-09-2009, 06:25 PM
Oh yeah, for about the dimming lights.....

If you've got lights dimming with a single 250wpc amp, there are other problems outside of the system itself. Deal with those first before moving on to amp decisions.



the entire house needs rewiring, no doubt. big 1950 'California Ranch' house, wired with a single 100A main feed and only a very few 15A circuits for outlets. right now, there's only one wall outlet even close to my stereo, and its shared with my computer systems which are all on a big UPS.

The GFA585 owners manual (http://www.adcom.com/data/manuals/gfa585manual.pdf) states that it can deliver upwards of 100 amps into low impedance loads, has 72000 uF of filter capacitance, and states...

...plug into a standard grounded 120V/60hz outlet with a minimum capacity of 15 amps and should have a dedicated branch circuit ...in some systems using very low impedance highly reactive loudspeakers, a dedicated 20 amp branch circuit is recommended....

I'd have to re-wire this wing of the house, not an easy task with the way the house is constructed (concrete slab, so wiring has to be overhead, and very low sloped roof, so very small overhead crawlspace for wiring access, and vintage wood paneling in the living room, so in-wall wiring is going to be difficult). What I'd ideally do would be to bring 3 seperate legs of romex down here from the main breaker panel, each on their own 15A breaker, one for my computers, one for the amp, and one for the rest of the stereo with about 6 outlets... being careful that both the amp and rest-of-stereo circuits are the on the same phase.

05-10-2009, 03:36 AM
Get the rewiring done if you want to run the heavy iron. Our house was built in 1954 with 100A service, and I was 'dimming lights' quite a lot.

Cost about $2k to get it to 200A with 2 dedicated 20A outlets (one for my computers and one for audio), and some new wiring, etc. All the toys are happy now. :bouncy:

05-11-2009, 08:51 PM
I think the biggest issue isn't dimming lights when the power supply first comes up, I think it's the line sag you get when the amp starts to really draw against the wall. If you run it off of the same breaker as a plasma TV you might only be getting 115 or fewer volts to the amp. Most output stages have an unregulated power supply to the output transistors. When the line voltage sags so does the output power. I'm not saying you would really notice it but it's something to think about.

When I used L100t's with my main system I drove them with an Adcom 5802 (I changed amps more than speakers in those days). It's probably the best of both amps you're considering, more power and MOSFET output. We have the speakers in another room now running off of a large receiver at about 100 wpc. They definately liked running off of a big amp better than a small amp.