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December 29, 2014 / billo44

Abby Clones

Made these over the summer after finding a pair of Fostex FE 167E drivers in

the junk shop.

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They are based on a design by Cain and Cain and called Abbys.

They also owe something to the Voigt Tapered Quarter wave pipe.

My friend David helped with the tricky bit clamping and glueing the cabinets together one weekend this summer.

After a good long time running in the drivers they sound pretty good.   Finally I got a speaker switch on Yahoo so I can compare the Clabbys (cloned abbys, not my pun…) with my Crysler CE 1II.  Repainted the switch in gold hammerite, the gold lame boob tube of the paint kingdom, and updated the speaker terminals.

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Note the 8 Ohm dummy load so I can listen to the EL 34 single ended amp through headphones.

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November 6, 2013 / billo44

EL34 ultra linear single ended amp. Designed by Iwamura Yasuo

This amp caught my eye when I was looking for my next project late 2012.

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I have been buying parts little by little since January 2013.

This amp was one of four amps designed by well known Japanese designers, sponsored by the transformer maker Noguchi.  The contest was to make the best EL34 amp for under 400 USD.   The four amps were featured in the audio magazine MJ.  I picked this one based on looks and the performance curves (since I can’t read Japanese).

For a time they were offering a kit with the four transformers and an aluminium box pre-cut… but they were out of stock by the time I got around to ordering.

This is my study build in a nasty plain aluminum box.  Next I hope move it into a nicer (and bigger) case with a wooden front and sides and maybe a brass top.

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Here is a dry build without everything hooked up underneath.

I am using Russian made electro harmonix EL34/6CA7 EH tubes.

I was lucky to find Matsushita 6SJ7GT (glass tube) on auction, and I had an old Matsuhita rectifier tube (nice flat top).

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Here is the case with all the holes cut out as per the plan.

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Showing the first problem , there isn’t enough room for the alps blue pot, I want to use, and the second problem…

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It’s all very crowded near the transformer terminals.

Lesson learned is that I need a case at least 50 mm deeper front to back… Never mind, for now I will move the pot over to the right…

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The large knob (Ooh err) covers up the original holes.

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11-02-2013

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Local 100v AC supply has an un-polarised plug  although myself I will use a polarised three pin plug with safety earth.

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11-06-2013 Getting closer to ‘smoke test’ time.  One heater wire still adrift, the input wires and the lug boards to finish….IMG_7075

Here are the remaining parts of the circuit mounted on lug boards.

Note the lug boards screwed to special tool #14, a grubby bit of plank, to secure them for soldering (special tools 1~13 are all various types of special stick).

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Getting ready for the Smoke Test… 8Ω 200W dummy load, variac, bulb tester, safety glasses….

Got some knackered old speakers to try if the first test goes OK.

Also have an old signal generator, 2 channel audio voltmeter, oscilloscope ready but don’t really know how to use them yet.  Planning to learn!  Any advice or links?

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Here we are with all the dots joined up at last….

This was a first for me since it has been my first point to point build from a schematic without the support of a forum and without build instructions (that I could read).

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Smoke test was negative…  the amp is now running in on the bench… Sounds good!

Ahhh!  Need to find a way to contact Mr. Iwamura. the designer to say thanks, it really sounds nice!

September 23, 2013 / billo44

CD Klon (Shigaclone) Mark II ‘Classic’

Here is the Mark II CD player with separate board and laser using original black gates for power supply and C.  Still a work in progress, but I can’t stop listening to it long enough to finish it…

Note also integrated power supply.  Needs a lot of tidying…

Front view

IMG_6228 With a ‘butty box’ enclosure for the exposed 100 VAC bits…

Trying out a different laser unit which sounds fine…

The DAC behind is one of Peter Daniels non oversampling DAC Kits AFAIK no longer available in this form, but still sounding great.

September 4, 2013 / billo44

Trio W-38

This was a very lucky find in a junk shop in early 2011. Face

1,500 Yen or about 15 US Dollars these days.  Dates from 1961 or 62 which makes it older than me…

I set about trying to restore this one and was helped out by various folk; Bob, just outside Boston, was very helpful, and various folks on the UK Vintage Radio Repair and Restoration forum (link at the bottom), Andrew G. who had painstakingly built an excellent amp from the amplifier stage of his W-38.  He compared the sound favourably with the legendary Quad 2 amplifiers which got me thinking!  (Cant comment on that  since I have still never heard a Quad 2…).

When I started work on the amp/receiver there was very little output.

Here is the top side after cleaning…

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And here is the underside with a lot of electrolytic capacitors in need of replacement.

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Not a circuit board in sight, all wired point-to-point.

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And after replacing 98% of the capacitors…

Still sounded terrible!

My friend Bob suggested I try the headphone output, and it was OK so I worked through the signal with an oscilloscope and found a dirty speaker phase switch  I cleaned all the signal path slide switches and replaced the final 2% of the leaky electrolytic capacitors and the thing woke up and sounded lovely playing through the aux input.

After about three weeks of re-listening to favourite albums I then got around to fitting a direct input to the amp stage.

Trio W38 direct in (4)

Connects to pin 1 of the front two of the 6BM8 valves.

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This is a pretty inconspicuous and fully reversible modification, mounted using existing screws… but leaves the volume control on the back of the unit.  This is OK by me…!

The volume control on the front doesn’t do anything! ….. I hate it when people turn down the music while I am listening to something inspired!

The switch selects from direct input or input via the original pre-amp stage.

Its very discreet with the lid back on….

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Had to listen to all my favourite recordings again for three weeks….

Still one of my favourite sounding amps to date… I am looking for another W-38 which is cosmetically bad enough to cannibalise for a nice sounding 10 Watt  power amp.

Note also the obligatory upgrade to the AC mains lead including the addition of a safety ground for the chassis.

And here are the links…

http://www.vintage-radio.net/forum/showthread.php?t=57768

and

http://85.92.85.233/forum/forum/showthread.php?t=67837

Bored you now!…

May 5, 2012 / billo44

My Ref Revision C Ultimate GB (Green Mountain Edition)

I first built this amp in early 2011 and then added the headphone output and new front panel in 2012 This amp is based on a design by Mauro Penasa.  This is the Revision C version with Ultimate bill of materials.

There was a group buy on the DIY Audio forum, and I bought a couple of boards.  I did not contribute anything to the design, I am just soldering by numbers. Those on the forum with real knowledge discussed and chose the best components aiming for a superb sounding amp at a very reasonable price.  Many thanks to  Uriah for all the hard work and to Sonidas for helping kitting up and packing/posting.

With the help of the build guide thread Dario organised, I got down to populating the boards….  (sounds a bit rude)!

Then there was the PSU for the lightspeed pre-amp… Thanks to Regi for kind advice.

And also thanks to my father Mike who was visiting and worked out the PSU circuit on the board.

Here we are testing the power supply unit.

Here is the lightspeed pre amp which basically uses light dependent resistors to control the incoming

audio signal volume thus eliminating noise and signal degradation from the volume control potentiometer.

Note my regrettable tendency to plait wiring… there is no excuse for this beyond the fact that I am

still a hippy at heart.

Next, trying to find a good  layout for all the ‘bits’ (technical term!).

Which was a complete waste of time, because I then patched the whole thing together from a different angle….

By popular (and very verbal) request I added a headphone output circuit!

Eventually I will have to commit ritual suicide by disembowelment, because the headphone jack is not mounted quite square (and I spilled beer on the the front of the amp), but I have been persuaded to put this event off for a while (thank you David).

Splendid Bakelite knob that though eh!

The wooden sides are made from Keyaki wood (Zelcova) which rubs up nice with a bit of Watco oil!

Sitting on top of the trusty old Marantz… on top of the 101 db/w 1969/70 Crysler Living Audio CE1-acII speakers, a much underrated Japanese brand

The thing sounds very fine to me!

The cast iron shell mark on the front panel is from a part from an old discontinued Vermont Castings Fireplace, and the top cover is a cast iron  floor register.  In the formative years Vermont Castings had gifted artistic designers working for them and they chose motifs and design styles based on New England furniture and architecture, such as this shell mark design.

I expect I bored you now….

Bill

January 15, 2012 / billo44

CD Transport (Shigaclone) Version 1, 2011

This idea was started by the Quest for a decent CD player at a low price and by two threads on the DIY Audio forum…

The main thread is now over 500 pages long;-

http://www.diyaudio.com/forums/digital-source/120229-finally-affordable-cd-transport-shigaclone-story.html

Fortunately it has been summed up here;-

http://www.diyaudio.com/forums/audio-sector/160373-cd-transport.html

DIY audio folk in Poland realised the laser unit from a cheap JVC boom box was the same drive unit as used in one of the current high-end CD players much praised by Audiophiles (I’m ignoring a big grey area there!).

The original player is called a Shigaraki, hence the DIY copy is often called a Shigaclone

The main problem with this DIY CD drive is that the original JVC donor boombox is now very hard to find, especially here in Japan.

However I got lucky and found a Sanyo boombox which used the same CD unit.  Unfortunately this is getting hard to find now also.

After stripping the boombox for all the parts needed, this is what you have left….

The remote, the control board, the laser unit and board, and the magnetic puck from the CD door.

Then to set it up on a test bed…. I used a rejected cast iron stove griddle from the skip (dumpster) at work for the base.  Cast iron is very heavy, damps vibrations and is relatively easy to work (but dirty).

Note the high quality ‘butty-box’ enclosure for the first power transformer!

About this time I had a lucky find in an old salvaged Aiwa amp (beyond repair)… a nice small toroidal transformer about the correct rating.

I salvaged the rectifier and fuse part of the circuit board and made up a proper power supply.

The original recommended voltage regulator (to step down to 8v DC) used black gate capacitors which are now very hard to find.  My version, following the suggestions of folks on the forum, uses two Rubycon ZL 1000 uF 25v, the input side capacitor is by-passed with a Nichicon fine gold 33 uF 16v.  The regulator is an LM7808.

The required directions for modifying the main board are found on the DIY forum, mostly removing a few capacitors and replacing one or two.  The summary thread has all the details.

Power is fed into the board where a choke has been removed.  The digital output from the board is used to feed a separate DAC (digital analogue converter) for the audio output.

I tapped the control/display board for wires for the required five buttons, play, FF, rewind, stop, and the ‘door’ button which connects to the original door switch position to instruct the player to read the CD table of contents.

Here we are with most of the work done and the base cut to size waiting for the enclosure.

The simple wooden enclosure with a cut away for the display, and a back plate for teh digital out and power in plugs. This is only required because I glued the frame together too early, during an inspired moment!

From the top showing the regulator which uses the cast iron base as its heat sink, display board, main board/laser and buttons.  Here you can see the exposed laser lens (maybe, assuming you know what they look like), you can be blinded by the laser from a CD drive, so be very careful not to look at this when the unit is powered up (obligatory sensible safety warning!).  This is the reason most CD players have a door with a built in safety switch so that the laser will not operate with the door open.

Here with the acrylic top fitted but not yet ‘brushed’, the power supply to the right (I know… boring box…).

And here the finished drive with a brushed acrylic top.

I’ve just started work on Mk II with various improvements…

Thanks to Peter Daniels as the prime mover on the above CD transport forum, and to all the other valued contributors.  Peter is very free with his expert advice and encouragement and has the experience and instinct required to cut through the BS.

The finished player sounds very good to me!

In the end this is all a subjective listening judgement, some serious people pooh pooh the whole thing.  I can only trust my ears and stick with the particular flavour of BS  that I personally chose to subscribe to.  I have to admit that investing time and money (even a little money) into a thing pre-disposes one to pass favourable judgments on said thing….

I bored you again….!

Off dear!

January 1, 2012 / billo44

Trio W-46K Restoration

Here is a short blog relating the joys of twiddling with a Trio W-46K.

In pursuit of aural pleasure, I purchased this 1966 amp at an online auction.

First job was to find some space on the bench….. Here is the bench ‘after’.

In antici……….pation of the arrival of the postman!  Note liquid refreshment (local Sake), and also an earlier 1962 (older than me!) Trio W-38 receiver/amp lurking.

Below is the Trio W-46K with the top removed, the thing was not working on arrival.

Some information about the amp according to Audio Heritage (great site and a mine of useless information)   http://www.audio-heritage.jp/TRIO-KENWOOD/amp/w-46.html

(Jap-lish (bad English) translation courtesy of Google chrome auto translator)

‘As high-end home, Amplifier was developed for companies such as coffee shops and also played on.
W-46 as a kit model was also sold W-46K.`

No to be deterred (either by the bad translation, or the not working amplifier) I set about restoring the thing…

After a good general cleaning.  I noticed one of the input wires from pre-amp stage to power amp stage was no longer attached.

Fixed that and also went around the worst looking bits of ‘dry’ solder fixing them up…  Checked the valves and replaced three of five 12AX7 in the pre-amp stage (had some to hand).  In one socket there was a 12AT7 (might have been a deliberate de-rate?).  After that I still only had sound from one channel and plenty of hum.

Removed, stripped down and cleaned the `source` and `stereo/mono` switches… avoid stripping these down if you can!  Very fiddly to get back together and I could have cleaned them well enough without dismantling.

Now I had sound from both channels.  `Snap crackle pop` from the potentiometers was cured to a large extent by liberal applications of `de-oxit`, but I will look to replace these in good time.  Does any one know where to find 1 Meg Ohm A and 1 Meg Ohm C dual gang potentiometers?

The schematic is courtesy of Kenwood Japan.

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Next I started replacing capacitors, the large triple cap and one other large can I left in place bypassed and grafted their replacements out of sight underneath.

Finally found the cause of the hum (98% of it anyway) was two leaky electrolytic caps C211 and C311.

Went ahead and replaced pretty much all the other electrolytcs, used cheap yellow polyester film caps (Cricklewood electronics) in the signal path…, excellent value for money.

Sounding pretty good by this stage.  I also found 4 good quality 7198A output tubes online which was quite lucky, these made another noticeable improvement in sound quality.

I replaced a few signal wires, and grafted better quality RCA plugs onto the AUX input.

Finally I fitted a modern AC power lead (with an earth!).

Had all these `bits` left over when I had finished…. also a couple of fast recovery diodes….

Now the amp sits on top of a trusty old Marantz CD-80 and sounds great considering it all cost bu–er-all.  Doing double duty as a room heater since it does give off quite a lot of heat.  Speakers are currently Crysler CE-1acII, which are very late 60’s and rated at 101 dB/W and sound good with tube gear.  Seems like a good match.

It would probably be worthwhile to try a direct input to the power amp stage and shorten the tortuously long signal paths, but it sounds pretty good for now.

I expect I bored you now, though if you got this far, you likely have similar problems too.

Happy New Year Folks!