Somehow I missed your post. Sorry about that. Anyway, having built Seal Electronics Opti-Mos I can say for my "ears" I am very pleased. Having owned various speakers in the Klipsch line since 87' I have tried many different SS amps in an effort to find one that didn't impart the hardness with horn loaded speakers that SS is known for. Until the Opti-Mos (O/M) I exclusively used Mcintosh power amps and preamps. While tubes offered a wonderful midrange and top end I always found them lacking punch in the bass. (I'm not much of a guitar player but I won't have anything except a tube amp here!) Over the years Mac has become ridiculously expensive which eventually led me into DIY. My first DIY amp was one of Hugh Dean's
(Aspen Amplifiers)AKSA 55W kits. I was totally amazed at the level of sound quality and value it offered. At the time I had an Adcom GFA-535 in my HT system. That little 55W AKSA flat blew the Adcom away top to bottom. Hmmm I thought, "There must be something to this DIY thing." At that point I was hooked. In the meantime I found it necessary to educate myself in basic electronics so I asked the wife to pick me up a electronics 101 book on her next trip to the library. What she brought home was a basic electricity and electronics text book written by Randy Slone of Seal Electronics. After a number of lengthly phone conversations I purchased one of his O/M kits. The rest is history. To get back to your question, Randy has developed what he calls a soft clip circuit that basically emulates the soft clip of a over driven tube. So I felt this would be a good test for a pair of KSF 10.5's I have in a HT system. This speaker gets real bright rather quickly as the volume is turned up. Simply put I was blown away at what I heard next. Sweet and smooth through the mids and top end. Yep without any doubt the soft clip circuit showed it's worth. What about the bass you ask? Well I'm old school in that if you want realistic bass it takes big power and the 200W O/M has it in spades. Best bass response I have ever heard period. Clean, deep and tight. Again this is only my opinion as "sound" is subjective to the listener.

Seal Electronics will introduce a discrete Class-A preamp in the near future. A new amp called the Totem Pole which by the way can be operated in Class-A is available now.

Thanks,
Brad Kizer

If you build another kit sometime and have a digital camera, maybe you could post some pics of the build-up. Sounds interesting.

Be sure to post on this thread, where I've specifically asked for information about the amp. That will keep the rules for general forums in order.

Did I over step the posting rules by mentioning Seal Electronics new product releases? It appears that I might have. If so please edit my post so that I am in line with the "Posting Rules". My humble apologies.

I'm pretty interested in this amp, and I think others may be as well. That's why I asked about it. I hope some of the High Efficiency folks will see this, as it appears to be a viable alternative to higher-powered push-pull valve amps. Lots of horn enthusiasts like push-pull tube amps for subwoofers and other applications that need some oomph.

We're all having a blast here, if you ask me! Thanks for posting!

Let me start by telling you a little about my self, I am an automotive technician by trade, and just started with electronics as a hobby. I have only built one PCB project and got hooked (IR 12 relay control board I use for my theater lighting). It was time for me to look for anther project to build, when my brother in-law said why don’t you build an audio amplifier, I laughed at him and thought he was crazy! But then I got curios and started my research on the web. When I realized that it was possible to build my own audio amplifier,I furthered my research and found many different amplifier kits, from very simple ones, to more complicated ones. By this time I had my goals set, not just to build any ordinary audio amplifier, but to build ultimate amplifier, something I can use for my home theater system,that is better then I already have! In my year long research, I heard a lot of good things about Randy Slone and his OPTI-MOS amplifiers. I purchased one of his books (High Power Audio Construction manual) and decided to build one of his amplifiers, even thought it looked more complicated. People were comparing it to some major high end power amplifiers, and I had to hear it for my self. I finally ordered my two OTI-MOS amplifier modules and his auxiliary control board. When I received the parts I was blown away the quality of the parts, BIG heat sinks weighing in at one pound each, that’s were I new these were some serious amplifiers, so the construction began. I started with the auxiliary control board, which was a little hard at first because component placements are not marked on the PCB,but once you get started it’s not too bad. I completed and tested the auxiliary control board with no problems, and was ready to start on the amplifier modules. I found that the best way to start is to do your inventory and separate all the components into groups at the same time, this saves a lot of time. Assembling the amplifier modules were time consuming but pretty straight forward, I had no problems at all. By this time I had to start thinking about the power supply,and the enclosure, I had a five disk CD player that never worked well from brand new,so I gutted it out and modified the face plate and using it as the case for now,because my plan is two build a 4 or 5 channel amplifier. These amplifier modules are easy to incorporate into any enclosure,which is a good thing because I’m not too good with working with metal. Now it came down to the power supply, by this time Randy Slone had come out with his new low impedance power supply board that I seen on the ZUS audio web site, when I saw that board I had to have it, because it was a nice clean set up. So I finally got my power supply (800VA 50+50 transformer) and low impedance board with 80,000uf of capacitor reserve, now all I had to do was wire it up. The wiring didn’t take two long; by this time I was getting a little nervous, but that’s what it’s all about, getting that adrenalin flowing. Once the wiring was done all I had to do was to set the bias which consisted of measuring DC voltage between to clearly marked points on the PCB, and it was ready to rock!!!!!!! When I heard it for the first time it blow me away! This has to be the best sounding amp I ever heard!! It has excellent bass control and a wicked top end I am very pleased!!! I will post pictures as soon as I can figure it out! I am a newbie at this whole thing. One more thing did I mention it has power to spare!! It’s running two pairs of speakers (15” Cerwin Vega D9’s and energy C7’s) and it barley gets hot!

Pat Ciardullo