DIY Audio Projects Forum

I note this day to the history as the day I finished my ODDBLOCK. Woooww man, this thing sounds amazing eventhough I used some secondary quality parts and still using test speakers since this is a prototype. I really mean it cause I haven't even used it with my Sonus Faber speakers yet. There is just a very small amount of hum you hear when you put your ears on the speakers otherwise you don't hear any hum or a thing.
I haven't put a feedback circuit. I'll decide it after hearing it with Sonus Faber.
Bruce, I'm grateful to you for your patience against my never ending questions and all your helps during this long journey and also to the other friends who is sharing all their experiences on this forum. I couldn't accomplish it without you.

My bests,
Ozan

Oh Bruce, what a BEAST you created!!

It is now in an unbelievable level after I connected it to Sonus Faber. I just can't believe it..

No hum with Sonus Faber...

time to see if you can get a self inverting pushpull work on KT150 Bruce

Some further analysis:
The first thing I notice about The Beast (Oddblock) is its grip on the speaker. This grip is probably the reason why the resulting sound is so fast but under control. This thing is greedy about outputting all the nuances and I can't think a tube amplifier faster than The Beast doing this. You feel the muscles while it is performing. That's why I call it "The Beast". This is not a whoopy loopy slopy kind of amplifier. I heard some high end tube amplifiers with my ears, though not the top high end. I believe this thing can easily find a good place among them.

Nice one Ozan.
I love mine as well, it's an amazingly detailed amplifier with a deep (but balanced bass) beautiful detailed mids and clear airy extended highs.
Mine build has a 3 position feedback switch that selects between: Bruce's FB, Zero feedback and a point roughly halfway between these two.
I do like the zero feedback and you describe it well above - but have found once I past the "DIY honeymoon period" that the zero feedback can get a bit fatiguing.
Particularly with heavy complex music. On solo vocal or solo instruments zero feedback sounds great.
I have well damped speakers, so have settled on the mid point for now.

@ TIJ-NIKI the design does work with KT150s and this has been discussed earlier. My CCS sensing resistor (bias) adjustment allows for 120 - 160ma
I can try them one day - but at double the cost of a KT120 for probably negligible sonic gain ) I cant justify it (they do look awesome though.

I used to like soft sounding amplifiers. Now, I really like the realism the beast puts on the table with a very clear portrait. The beast changed something in me. I listened to it 3 and a half hour with no interruption. Lots of clear detail but nothing harsh and no headache. Additionally, when I turn out the lights, I feel like I'm in a concert hall. I would change some parts I used in the prototype. After listening and now, I'm really really in doubt.

Hi, Yes the amps are fast and detailed with a really solid bottom end. I'm glad you like them, I certainly do. There is no particular advantage to using the KT150s other than the "wow" factor. The difference in output when translated into audio loudness is minimal. The cost of the tubes, larger output trannie (has to handle more DC current not audio watts) and possible issues with the CCS don't make it really a great idea. It has been tried with somewhat costly but mixed results. The KT120s do the job well. On the NFB...without it in place the amps are stable under about 99% of imaginable loads. It is there because of the very high level of output available above the audio band. When built with the parts listed they can deliver about 1/2 power at 100KHZ and full power out to about 70K. Far more than needed. The NFB brings the 1/2 power to about 50K and full power to about 35K. Just enough. I prefer using it. Signal to noise is slightly improved and resistance to EMI is a bit better.

Good listening
Bruce

_________________
Some of my DIY Tube Amplifier Projects:

• PoddWatt: 5751 / EL84 Push-Pull DIY Tube Amplifier Project
• OddBlocks: KT88 Push-Pull DIY Tube Amplifiers (Mono Blocks)
• ForeWatt: ECC802S (12AU7 / ECC82) DIY Tube Preamplifier Project
• GrooveWatt: Tube (Valve) RIAA Phono Preamplifier Project

Bruce,
Do you compare oddblocks with other high end tube amplifiers? You play down a little bit, but this one is real good.

Hi, A number of folks have done that for us. Some of the customers of the commercial site have dumped rather costly gear for some of our amps. When I go to audio shows I listen carefully to other amps. It is true that the set ups are difficult to get right in such settings (I know we had fun setting up a few times) but you can tell a lot about amps if you listen carefully. I would put a pair of the KT120 amps up against any others. But then I am a bit prejudiced . When price / cost is a consideration especially for diy I don't think there is much competition.

Now for the disclaimer....I try not to do anything that has commercial implications on forums and recommend that folks seek out and listen to gear on their own. My opinions are my own only.

That said...have a great holiday period. I plan to.

Good listening
Bruce

_________________
Some of my DIY Tube Amplifier Projects:

• PoddWatt: 5751 / EL84 Push-Pull DIY Tube Amplifier Project
• OddBlocks: KT88 Push-Pull DIY Tube Amplifiers (Mono Blocks)
• ForeWatt: ECC802S (12AU7 / ECC82) DIY Tube Preamplifier Project
• GrooveWatt: Tube (Valve) RIAA Phono Preamplifier Project

I have built your poddwatt, forewatt, grovewatt and not the blocks and I can say that the prejudice is real, not for the price but for the self inverting method. "no phase inverter?, is it a set? You use an internal transformer? Wait.. Lm317? Omg that is sooo ridiculous" and basically walk away. I have a feeling that those little cheap chips hurt the pride of many