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PostPosted: 16 Sep 2009, 19:47 
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After I have stuffed the PCBs I go back to the chassis and do the point to point connections. I don't mount the transformers yet as it seems much easier to put the amp together without the (heavy) transformers attached. The masking tape identifies the loose wires.
Attachment:
OddBlock-KT88-Series-1-Point-to-Point.jpg
Next I at attached the PCB and transformers and make the final connections. :!: Note that I had the diodes backwards in the PCB photo a few posts back! :!: Thanks Rodney for pointing that out as I had missed it when I checked for proper polarity! :hot: The diodes are placed correctly in the photo below.
Attachment:
OddBlock-KT88-Series-1-Connections.jpg
And some finished photos of the second monoblock. I'll take some better quality photos when I get a chance.
Attachment:
OddBlock-KT88-Series-1-top.jpg
Attachment:
OddBlock-KT88-Series-1-rear.jpg
I'm really enjoying the amps right now :king: but eventually I get them on the scope ... :ugeek:


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PostPosted: 16 Sep 2009, 19:54 
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Its a thing of beauty Gio. Nice work.
Bruce is coming to the Audio Get Together :) I get to hear them!
Uriah

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PostPosted: 16 Sep 2009, 20:27 
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Yes! I had heard that from Bruce. Hopefully there will be a F5 that you guys can compare. My F5 is a few months away - so far I only have the PCBs. :(

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PostPosted: 17 Sep 2009, 06:42 
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RiGuy wrote:
Its a thing of beauty Gio. Nice work.
Bruce is coming to the Audio Get Together :) I get to hear them!

Damn it would be great to hear Bruce's OddWatts matched up against an F5. Maybe I'll check on flights again. :idea:

Gio, what board are you going to use for your F5? Did I miss a good group buy?

Alan

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PostPosted: 17 Sep 2009, 07:14 
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He got them from Peter Daniels at Audiosector.com
Uriah

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PostPosted: 19 Sep 2009, 16:45 
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Hi Everyone, Excuse my ignorance for not knowing, what's an F5? I was tinkering with my system today and swapped out the OBs and put in the amp I use as a reference. A vintage SS Marantz 1060. It has always been a good sounding amp. It still is, but when put on the Martin Logans (and using my tube preamp that has no name yet) it just came out second. It still was very nice, but seemed edgy and the top end didn't soar like I expect from the OBs.

I will probably bring the Marantz to the meet just to see how others feel. I do plan on bringing the original Odd Block project amps and a pair of the early production kit ones as well. I would love to bring the ML speakers, but they aren't designed for travel and even if I did we would probably spend most of the day getting them set just right. How to go about this might make a good thread on another part of the forum.

Good listening
Bruce

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PostPosted: 19 Sep 2009, 18:43 
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Bruce,
Its only the best sounding Class A SS there is!! :) Well, that I have heard anyway. I have heard a tube that blew it away.
http://www.firstwatt.com/downloads/F5-om_sm-080527.pdf
Uriah

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PostPosted: 23 Sep 2009, 16:52 
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Hi Everyone, I checked on the F5. I actually saw the material before - just spaced out on it. I agree completely with the design concept of first watt. All the Oddwatts are designed to be very accurate and quiet at low power output levels. That is a primary reason for using class A operation. Careful matching of the components also plays a big role in this area. I am constantly getting email about various substitutions and the effect on the sound. Some are good, many are not. For example, using different output transformers. Fine, except the NFB loop is based on the characteristics of the ones specified. Others may work, but the NFB may not be correct. The results are unpredictable. It might be better, then again maybe not. There are numerous ways to model the behavoir of the changes and they do provide some insight. Unfortunately the wide range of tolerances combined with inaccurate parameters (specs from manufacturers for example) can easily turn what seems a good circuit into one that is marginal at best. Enuf' soap box. Austin will be fun.

Good listening
Bruce

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PostPosted: 23 Sep 2009, 18:51 
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Those are looking really nice Gio. :up: This is beginning to motivate me to get working on my Williamson amp again now that I have a decent preamp to use on it. :P I need to try one of these F5's everyone is raving about too but I have to finish that little LA4270 hybrid amp first, and still need a good supply for my IRF640 headamp, so I've got lots of projects to finish up.

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PostPosted: 24 Oct 2009, 15:34 
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This is a photo from two weeks back where I tried out the OddWatts with a DIY Lightspeed Passive Attenuator. The source here is a NAD C521i CDP.
Attachment:
KT88-OddWatt+Lightspeed-Attenuator.jpg
I have over 100 hours on the OddWatts now and I am very pleased with them - enough so that a couple of my other DIY amps will be disassembled for parts. I checked the bias again and it was within about 1mA.

Later I added a Behringer SRC2496 DAC / ADC into the mix.


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