My sincerest apologies; My communications have been terribly slow, and my turn-around time for refurbished equipment is getting out of hand. I have customers waiting up to four months for their equipment, and that’s no good. I wouldn’t want to wait that long!
I never anticipated such a level of interest! Many thanks to all of my customers; it’s a pleasure to help you build your music systems, and I love hearing people’s comments after they get their gear back.
I like to say “YES!” to everyone’s projects, but I have taken on more work than I can possibly keep up with. I am buried in emails, and it’s getting hard to find time to work at the bench. Things are snow-balling on me.
It’s a good problem to have. It means I’m succeeding, but I won’t be for long if I don’t limit the scope of what I do.
Adcom GFA-535 owners; Has it always bugged you, how the right channel of your amp buzzes through your speakers more than the left channel? Yeah, me too. The buzz is a buzz-kill… so I killed the buzz! With this thing I made.
Now, the GFA-535 is a legendary little amplifier, deserving plenty of buzz, but it’s too bad so much of it comes out the speakers. Oddly, the GFA-535’s bigger sibling—the GFA-545—using the exact same amplifier boards as the 535, is nearly silent as a stone. What’s going on?
The Adcom GFP-750 preamp was designed as a companion piece to the GFA-5802, with matching aesthetics. It’s a MOSFET based, single-ended Class-A preamp designed by Nelson Pass. Conceptually, it’s similar to the Pass Aleph P and the ‘Bride of Son of Zen’ DIY project.
Here’s a custom GFA-555 I built for Mark in Michigan. This is a fully dual-mono conversion with all the tweaks. Each channel has its own, dedicated 500VA transformer, for 1000VA in total, replacing the single, 850VA stock unit.
Hi Everyone, it’s been a long time since my last blog entry. I’ve been so busy refurbishing amps and preamps! My wait times are getting a little long, but that’s a good problem to have. Customer emails were getting hard to track, so I’ve implemented Freshdesk, a cloud-based helpdesk ticketing system. (No affiliation.) Highly recommended! I can set due dates and track status, how long since I last contacted someone, etc… It’s reduced my own stress and improved my customer service. My queue may be long, but my customers are kept well informed.
Even better! I made a few revisions to the original boards, and I can now say that these are better quality boards than the originals! These have plated through-holes for a more solid solder connection, and greater pad strength. They are also less affected by heat cycling. Even with poor soldering, a plated through-hole is extremely reliable.
How many inputs do you really need? For my second system, at my workbench, I really only need one, and that’s to listen to whatever is playing on the main system.
Few people have heard of this product, but for a short time, Adcom made a great little 50WPC integrated amp called the GCA-510. (Good Control Amp ,where’s the F?) It was essentially a GFA-535 with a smaller, lower-voltage power supply, and a passive preamp built in. Apparently, Adcom was going after the UK market, land of small but high-quality integrated amps. (More people sharing walls with neighbors, and we Yanks are so rude with our big amp stacks.)
Here’s an awesome amp I just finished for a customer in NYC. This was really fun to build! He wanted a high-current version of the GFA-545, so we went all-out with dual Avel 500VA transformers, gigantic 27,000uF filter caps, and a truly dual-mono layout throughout. This amp has dual power cords, fuses and power switches.
The sound is just incredible! Perhaps the best one yet. Super clean and powerful, and never seems runs out of gas, right up to clipping. I’d say it has an effortless sound to it. I measured 162W at 8 ohm and 272 at 4 ohm just before clipping! That’s only 50W short of a perfect doubling of power at half impedance. That is one stiff power supply!