Jump to content

Winter project


JunktionFET

Recommended Posts

Little known fact about Joe (maybe) is that I'm an audiophile. I love vacuum tubes, analog technology, vinyl, and high quality loudspeakers. I'm mostly into vintage equipment, or new equipment with fairly simple circuitry. I find that music sounds more organic or natural when there's less "stuff" in the way. I've designed and built speakers and crossovers of my own, and have refurbished old speakers with new veneer and components.

One of my best friends (since middle school) is a brilliant electrical engineer. He too is into high end audio, except he designs and builds his own amplifiers. On countless nights we've auditioned various designs, trying to find the clearest and more realistic sounding combination of parts.

Anyway, I've always liked the idea of "mono-blocks" as opposed to a single "integrated" stereo amplifier. Basically a "mono-block" is a single channel amplifier that is positioned very close to whatever loudspeaker it is attached to. The idea is that you perhaps get better stereo separation, but you also considerably shorten the length of current-bearing wire that connects the speaker. You have a stereo pre-amp (or receiver) of course which is what your input devices connect to, be it a PC, DVD player, turntable, etc.

Vacuum tube mono-blocks are usually stunning to look at because the power tubes are mounted on top of the chassis. The glow from the filaments and blue haze from the electron cloud inside are all part of the visual appeal:

_Issue22_images_Sixpac1_zpsfdb986ef.jpg

Years ago I had an idea to do something similar, but with solid state components. And being a car and Peugeot nerd, I wanted to make it somewhat car/engine themed. I figured I could use an intake manifold as a heat sink, and what better manifold to choose than the XN6! So my friend designed an amplifier circuit for me to build. It's one of the simplest amplifier designs known as "Single ended class A". There's just one output transistor and literally just a handful of ancillary parts. It's so simple in fact that you don't even need a PCB--you can just point-to-point wire the sucker together.

Fast forward to present day... Just the other night I dug the XN6 manifolds I collected those years ago out of storage. This winter is going to be the one where I actually follow through and build these mono blocks. Here are the manifolds. I think that once I mount them on top of a slim chassis, they're going to look slick. I intend to illuminate the inside of the runners with amber lighting, so this warm glow sort of emanates from the four ports.

2014-09-30183220_zps365bdb01.jpg

Link to comment
Share on other sites

Well, I have never heard of a mono block but the idea sounds intriguing.

I found out from dumb luck and from delving into audio that home speakers can be an easy rebuild. I have been finding high end units from garage sales (Boston Acoustics A60, A70s; Cerwin Vegas) and all they need is the woofer refoamed. The foam degrades after 25 years or so. Guaranteed.

The rebuild kits on ebay are like $25 or something. Easy diy. Comes with instructions. That's all they need from my experience.

I have heard it said that the old cabinets are heavier and better built. New in the early 80's the cost was over $200. You go to a garage sale, see some interesting examples, pull the cover off to expose the woofer foam. If its old, its probably in pieces, or you can poke it, and it crumbles.

I have bought several pairs, and the price has been in the $5-10 range. Chances are, if I don't buy them, no one will and they end up in a dumpster.

-Bill

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...