I have a pair of vintage (amp killers) Infinity RS 4.5’s which are well above my pay grade. I’m trying (on a small budget) to acquire amplification to drive them (Bi-amped) safely. Therefore I’ve been searching the used market. I’ve been offered an opportunity to purchase a pair of Haflers (9180 & 8270) along with a 945 pre-amp, all for $850. I have also been exposed to an opportunity to purchase some Adcoms (545ii’s). I don’t want to make a big mistake by purchasing something that isn’t up to the task. I’m dying to hear these speakers and would appreciate some counsel from you good folks. Thanks, in advance!
I don’t have any experience with the Haflers, but the Adcoms will drive the Infinities.
If I’m not mistaken, I think Nelson Pass was involved with the Adcom amps. His designs would ensure enough current.
The Adcom amps were slightly grainy as I recall. Nelson Pass designed the GFA-555 and is the sweet spot in the Adcom line. I had a Hafler preamp and amp in college for a short time. David Hafler was with Dynaco for some time and ventured out on his own with value oriented kit amplifiers. They were a good value in their day, but I’d steer clear of them today. They sound coarse to my ear. I changed from Hafler to GAS Son of Ampzilla with no regrets. Replaced the DH-101 preamp with an AGI 511a, again no regrets. Toyed with an early PS Audio phono preamp as well. Blew away the Hafler, IMO a better match at your price point would be Forte amplification. Built like a Brick Sh**-House. The Forte Model 3 is 200 WPC and a little sweeter sounding while still having an open and detailed sound. Another option is the Forte Model 4a, 50 WPC class A all the way. The Fortes have a robust power supply and don’t shy away from low impedance loads.
Partnered with Threshold preamps you can’t go wrong for vintage amps with these. The Forte preamps are just so-so IMO.
From what I’m seeing, the Forte amps might be out of my current price range? I do prefer to bi-amp these speakers. I’m wondering (since I do own an Adcom pre-amp), If I should buy one of this guy’s Adcom 545ii’s for the top sections and search for a GFA 555 to drive my bottom ends? It would certainly look nicer to have matching equipment but I wasn’t sure if the Adcoms would support the 2-3ohm dips?
I believe you are cutting your self short with the Adcom 545’s, IMHO. Just a thought, and a totally different direction, have you considered the PS Audio S300 used? One may just do the trick.
Agree there are many alternative options to consider, but if you want to stay with the Adcom/Halfer line, here are some considerations-
I can’t speak to the newer Halfer amps you referenced, however, used to help my dad build DH200/500 amps as a kid & I’ve owned both Adcom 545 & 555 as a young adult.
Both are great foundation points on a budget. With a few tweaks you can vastly improve their soundstage and remove much of the graininess/harshness @weedeewop referenced
Nelson has posted several options on DIYAudio, or if you prefer not to do it, Musical Concepts / Musical Design offers upgrades depending on the level you wish to take them.