Guest David H Posted April 1, 2014 Share Posted April 1, 2014 Recently I was surfing the forums and I saw mention of a Nelson Pass design, First Watt amplifier. Naturally I opened my big amateur advise giving mouth and said. "I have always wanted to build one of those" Almost instantly I received a PM from duder1982 that said "I have a set of the Pass F5 boards I am not going to use. I will give them to you if you start a thread about your build." I replied "yeah, sure, cool, awesome...." So here I am fulfilling my obligation, what a fun journey. Thanks duder, I love it. For the chassis I stepped up and purchased the premium pre drilled chassis from DIY Audio. In the mean time I stuffed the board with the available parts I had on hand, and ordered the JFets. The power supply I ordered from Antec, what a beast. The capacitor board I ordered from EBay. The engraving of the face plate I did in house, quite the learning experience, and what a mess. Dave 2 Quote Link to comment Share on other sites More sharing options...
Guest David H Posted April 1, 2014 Share Posted April 1, 2014 After the amp was assembled, and initial biasing was done, I allowed it to warm up the recommended 2 hours before re-biasing. In the mean time I had plenty of time to audition the amp. Really a great sounding unit. The only down side of this amp I can find is that it requires a lot of drive to achieve full output power. Fortunately I had and Amps and Sound SSP - battery operated preamp on hand that will drive damn near anything. I listened to all of the favorites, and I have to give Mr Pass credit, this is a fine piece of gear. Watt is Nelsons motto? What does it matter how much power you have If the first watt sounds like $hit. Quote Link to comment Share on other sites More sharing options...
Guest David H Posted April 1, 2014 Share Posted April 1, 2014 Biasing, and the Fubar. 2 hours has passed, that amp is warm and ready for the final tweaking. Biasing the amp properly requires 3 DVOM's I have 2 on hand, but I had an excellent idea! Why not use my dual trace scope with measurements function as a volt meter. Here is why: In doing this I burned up the JFET's on one channel. I don't recommend it. Boner move!!!!!! New FETS are on the way, as well as a few extra parts. Dave Quote Link to comment Share on other sites More sharing options...
The Dude Posted April 1, 2014 Share Posted April 1, 2014 (edited) All man I am glad to see come to life. Bummer about smoking the fets. Did you use you cnc machine to ingrave the faceplate. It looks really good. Goof job. Edited April 1, 2014 by duder1982 Quote Link to comment Share on other sites More sharing options...
HPower Posted April 1, 2014 Share Posted April 1, 2014 Great looking build Dave!!! I am not surprised you are liking the sound of the F5. I picked a used Rawson F5 up 3 or 4 months ago to try on my Cornscalas and I was also pleasently surprised. Swapping in the F5 for my main amp (Almarro A205A EL84 single-ended-pentode) is different flavor, and one that I enjoy. Several years ago I briefly tried a Rawson F3 with my then KHorns and it did not impress me as much as this F5 is. More pics , please! Quote Link to comment Share on other sites More sharing options...
jwc Posted April 2, 2014 Share Posted April 2, 2014 how cool Quote Link to comment Share on other sites More sharing options...
Guest David H Posted April 2, 2014 Share Posted April 2, 2014 Thanks, I appreciate the comments. Dave Quote Link to comment Share on other sites More sharing options...
Guest David H Posted April 2, 2014 Share Posted April 2, 2014 Did you use you cnc machine to ingrave the faceplate. It looks really good I did use the CNC, just had to slow it down to 40ipm, and a cut depth of .002" per pass. Dave Quote Link to comment Share on other sites More sharing options...
Deang Posted April 2, 2014 Share Posted April 2, 2014 Tim's builds certainly aren't as nice as Dave's, but he can get you behind the wheel of some really good sounding stuff without wiping out your checking account. Quote Link to comment Share on other sites More sharing options...
The Dude Posted April 2, 2014 Share Posted April 2, 2014 Dave would you by chance have any older McIntosh ss like a mc2505 or a short to compare these to. I sometimes are torn between selling some components I have to build the F5Tv2, to purchase another MC2505. Quote Link to comment Share on other sites More sharing options...
Guest David H Posted April 2, 2014 Share Posted April 2, 2014 I have an MC 2100 , which is another great sounding amp. Once I get the Pass up and running again I can do a head to head comparison. Dave Quote Link to comment Share on other sites More sharing options...
The Dude Posted April 2, 2014 Share Posted April 2, 2014 Cool, looking forward to that. Quote Link to comment Share on other sites More sharing options...
The Dude Posted April 2, 2014 Share Posted April 2, 2014 What transformer did you go with, I see antek is back up and running. I have 800va, from primerose transformers. You want to talk about a beast, I now know why some amplifiers are as heavy as they are. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted April 2, 2014 Share Posted April 2, 2014 Nice work, Dave... Quote Link to comment Share on other sites More sharing options...
HPower Posted April 2, 2014 Share Posted April 2, 2014 Tim's builds certainly aren't as nice as Dave's, but he can get you behind the wheel of some really good sounding stuff without wiping out your checking account. From what I just saw in Dave's post, I would have to agree with you Dean. I don't have the skills to take on such a project and I would bet that since Dave is building this for himself vs. Tim's "for profit" build (which he sure has taken some heat for in the DIY communite), I am sure Dave's will be a nicer machine. But for the 400 or so bucks that I paid, it is hard to complain about my F5. Once you have yours dialed in to your satisfaction Dave, it would be interesting to compare it with Nelson's "Real Mccoy" Quote Link to comment Share on other sites More sharing options...
The Dude Posted April 2, 2014 Share Posted April 2, 2014 But for the 400 or so bucks that I paid, it is hard to complain about my F5. Most spend that alone on the deluxe chassis for these. Once you have yours dialed in to your satisfaction Dave, it would be interesting to compare it with Nelson's "Real Mccoy" I all ways tell people that if the diy version sounds just as good as the Real Mccoy, I would just sell the Real Mccoy. Quote Link to comment Share on other sites More sharing options...
mark1101 Posted April 2, 2014 Share Posted April 2, 2014 Nice job. GotHover.........is there anything you can't do? I'm interested in the F5 - 2100 shootout. Quote Link to comment Share on other sites More sharing options...
Marvel Posted April 2, 2014 Share Posted April 2, 2014 Duder/Dave -- Are the boards from the DYAudio website, too? Nice CNC work on the front, Dave. That looks really good. Bruce Quote Link to comment Share on other sites More sharing options...
Guest David H Posted April 2, 2014 Share Posted April 2, 2014 Nice job. GotHover.........is there anything you can't do? I'm interested in the F5 - 2100 shootout. Yes, currently I cant move my right hand. I had carpal tunnel surgery at 7 am. Dave Quote Link to comment Share on other sites More sharing options...
Guest David H Posted April 2, 2014 Share Posted April 2, 2014 Duder/Dave -- Are the boards from the DYAudio website, too? Nice CNC work on the front, Dave. That looks really good. Bruce The boards are from the DIY Website. Thanks, Dave Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.