• 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.

Fred Nachbaur's "SET MiniBlok"

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L

lightspeed

Member
Joined 2011
#1
Hi Members,

Still pondering my first hifi tube build and found this interesting DIY build by the late Fred Nachbaur titled, 'Simple, Single-Ended-Triode Amplifier' aptly titled, 'SET MiniBlok'. After much reading, I am intigued with an SET amp despite some of it's quirks. The entire parts for the MiniBlok are about $100. Seems like a good first build (for the poweramp section of a tube hifi system).

The SET MiniBlok is low cost and appears to be a project I can complete. Also, it appears to be an approachable first build as it does not require me to jump-in deep waters and spend upwards of $500+ in parts. Building a more expensive, complicated and involved SET Monoblock build may find myself not being able to complete it. Eventually I would prefer to build two SET Minibloks for stereo.

I have years experience in wiring, soldering and drilling out a blank chassis (from scratch).

This 'SET Miniblok' amp puts out 1 watt and as a result, I need to match it with high sensitivity speakers (a.k.a efficient drivers) in order to produce an acceptable and usable volume level.

Question #1 please:
Is Fred Nachbaur's 1-watt SET MiniBlok DIY tube-amp still considered a viable approach to a first build?

Question #2 please:
Has anyone reviewed this SET MiniBlok amp project?

Question #3 please:
Is there still support for this project? I sadly learned that Fred Nachbaur passed away in 2004. However his website is still being hosted. See link below for description:

A Low-Cost Single-Ended Triode Amplifier

Thank you very much for your help.

uc


An externally hosted image should be here but it was not working when we last tested it.
 
#2
You said --"I have years of experience in wiring,soldering ----" as long as you are safety conscious as regards high voltages when working with tubes I don't see a problem as a "first build " .



I will let others answer Question #2 and Question #3.
 
#5
Unless you already own some high efficiency speakers, or plan to use it to power desktop speakers that you listen to nearfield, I would suggest that you look for a design that has at least a bit more power.

IMO, the best way to get into tubes is to start with an old console stereo amp and rebuild / modify it. If you're patient and look around you can often find derelict consoles for $25 to $50 locally and pull the parts. The most popular donors are Maganavox but there are plenty of other brands too. Check local yard sales, thrift stores, flea markets, Craigslist, etc. There are plenty on Ebay too, but you'll pay more.

Here's a few threads dealing with some of the popular Maggies:

Magnavox Flea Power: Getting More Out Of The 8600 Series - A Lot More! | Audiokarma Home Audio Stereo Discussion Forums

More Fun With Magnavox: The 9300 Series | Audiokarma Home Audio Stereo Discussion Forums

Rx For the Magnavox 8800 Series | Audiokarma Home Audio Stereo Discussion Forums
 
#6
Not sure if you got the answer you wanted. I don't think there is true support for Fred's site, it is just hosted statically.

There is nothing wrong with the MiniBlok design. If need support, you can lean on this forum.

It is an inexpensive design, 1 tube/channel, back-to-back power transformers. However, those cost saving tricks can be applied to other designs. You will have to buy an output transformer; the cost might surprise you.
 
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