• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

pictures miniblok 1 and miniblok 2 by fred nachbaur

just thought i would post the pictures since i bought a camera. hope you like.


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the SET amp definitely colors the sound, like that 50s clean guitar sound, but it is nice and the bass is very full for a small little amp like this. the PP is 3.5 watts vs the 1 watt and sounds more accurate. im still waiting to put in some better bypass capacitors on the cathodes. the ones i put in are low quality. i probably prefer the PP, it is clean and very HIFI to my ears. on fred's web site he compares the outputs and the harmonic frequency graphs and the PP is much lower in first order harmonics and the output frequency wave is almost identical to the input signal whereas the SET it is somewhat rounded.

thanks for commenting. :cheers:


2004-04-02 4:00 pm
Graphs are not the best indicators of sound. I've been wanting to do a little P-P like that so I'm encouraged by your comments. Depending on how efficient your speakers are the SET could be straining a bit. My 6EM7 SET sounds great on La Scala but sucks on mini monitors.
Hi Folks,

I built two of Fred's Miniblok's. Easy to build as a first tube project and still going strong. I had a conversation going with a couple of posters but I can't seem to find it. I might do a little Youtube video about the build, and my thoughts on this wonderful little amp.

Fred's build description kept the cost down but I spent more money than perhaps I should have for something that in my butterfingers might have turned out crap. Luckily for me it all turned out fine, and as a first project I would recommend it to anyone...

I'm fairly sure that no-one on this site knows as little about tube amps as I do, except the self-confessed noobs perhaps, but the great thing about this forum is that if you ask, there will usually be someone willing to pitch in. I know this from experience...
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2012-05-27 7:34 pm
i'm running them through a pair of celestion 5s vintage speakers they are about 89dB and it sounds great to me. yeah some of those very sensitive klipsch speakers would be fine but not necessary for my needs.(it is tempting though)

if you build the PP have fun and enjoy it does sound very good.

The thing about flea watt amps is that it may actually produce more music than you have previously realized but it will be unheard because the sensitivity is not high enough to reproduce the microdetails.