What happened? Well, you could see I’m still alive, kicking and soldering but more than that, I have spent more than a year improving on Discreet Monica.

I know, I know, I’m a pain in the arse but with each improvement, you learn a lot more. I improved on her layout, grounding and even incorporated a FPGA for signal processing capability.

Err, in layman’s term, I had to redo the PCB layout through a few revisions (very expensive process I tell you), learn a new (to me) programming language called VHDL (VHSIC Hardware Description Language but to me it means Very Hard Darned Language), program the FPGA to replicate what I had with 14 integrated chips previously, measure and hand match the high precision resistors (a royal pain I have to tell you) etc etc…

All this effort, so that she sounds better and she’s much easier to build. She definitely sounds so much better now but unfortunately, still tedious to build. Is there more to come? Sure there is! But save that for another day.

I then wanted to build a proper All-In-One system. You see, back when we participated in the KLIAV show way back in 2008, I built an All-In-One.

Back then we have the Monica3, Maggie, output transformer coupled 6GM8 and Charlize2 built in separate chassis and linked via interconnect cables, like a typical separate system.

Once built into a single chassis, the sonics gained a quantum leap!

Why so you ask? It could be lack of RCA interconnections, much shorter signal path and more crucially, the much much shorter return path (also known as GROUND) path between components. Simply put, the electrons travel in a much much shorter loop and they are happier :). And my electronics background tell me that the happier the electrons, the better the sound! And so it proved.

That was then, so I had to build something better today. Since we are going on a purist’ path here, might as well go all the way with just a single gain stage throughout the signal chain. And nothing is simpler than a one-tuber aka spud amp.

Over the years, have always wanted to build a spud and back then the popular tubes were 417, 5842 as well as 6C45. There are others but those are usually 2 stages in an envelope. I’m being purist here. I want ONE and ONE only.

The last few years, another tube gained popularity and it’s a Ruskie 6E5P tetrode. I learned a lot about this tube thanks to the fine work done by Bartola Valves as well as Romy the Cat.

Now this little fella is a like a super tube. Specs wise, everything rocks! So much so that I just have to build it!

Also, over the years, I have heard a lot about the parallel feed scheme. I’m not sure how many commercial amps out there have such a scheme. Just shows us hard core DIYers are more cutting edge than mainstream. Ha! So this is a fantastic vehicle to put in everything together.

And so, we have… A Purist’ Wet Dream.

The initial idea was to build this to be mounted on to a wall but since I’m a such a pain the arse, I just can not build a simple amplifier. So 2 power transformers, 2 power supply chokes, 2 plate chokes, 2 parallel feed output transformers and 4 beer cans oil capacitors later… this whole contraption is just too heavy to be mounted on the wall. So now it has legs and it’s going somewhere!

Input takes USB from your Music Machine be it Windoze or Mac and
Output goes to your speakers via the binding post

USB Input – Discreet Monica – modified Intact Audio Autoformer Volume Control – triode-wired 6E5P Magnequest Iron Parallel Feed Output – Speakers!

All in all, there is only ONE gain stage throughout.

Want to know more about this Purist’ Wet Dream? Stay tuned for the next article.

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Here, There and Everywhere

Here, making each day of the year Changing my life with a wave of her hand Nobody can deny that there’s something thereThere, running my hands through her hair Both of us thinking how good it can be 3655 Someone is speaking but she doesn’t know he’s there I want her everywhere and if she’s beside me I know I need never care But to love her is to need her everywhere Knowing that love is to share Each one believing that love never dies Watching her eyes and hoping I’m always there To be there and everywhere Here, there and everywhere

We have discontinued Maggie – the autoformer volume control, as we are developing something better, MUCH BETTER than ALL the transfomer volume controls we have tried. Watch out for her in April 2008!

Intro Ahhhhhh….. Elegance, Grace and Beauty. How else would you describe Maggie? Maggie is an autoformer volume control, designed and manufactured exclusively by the fine folks at Audiohobbyist.com And yours truly here got the most flattering honour of distributing such fine products, aligned with our aim of promoting great audio among our brethrens of this world! (Spread the word to our improverished brothers!) If you are wondering, why autoformer? Well, a true transformer volume control was built but the listening didn’t reveal that much of a difference. Could be that the autoformer is less lossy? However, the sonic difference between resistive pot and Maggie was totally unfair to… the resistive pot. To sum up in a very long line… smoother mids/highs, more “body” in the presentation, deeper bass, better dynamics/impact, (even at low volumes, you could hear the drummer hitting the drum hard and not slacking off)… But the best impression I get of Maggie is that, she makes the speakers “disappear”. I know this sounds like a damn cliched statement but I got less concious of the system. There’s something in the the music presentation! There’s something about Maggie… So after listening to Maggie, you’ll be wondering what the hell have you been missing in life listening to putty resistive volume controls. Ever experience the feeling of being in love for the very first time and that life before her was a big fat void?   Let’s face it. After your first taste of Maggie, you’ll be desiring for her, Here, There and Everywhere.

What’s the Impedance, Kenneth?   Maggie is about 60H in inductance. How does this translate to impedance depends on how “honest” you are. As Impedance is 2*PI*Frequency*Inductance, you could see that it depends on Frequency. So an honest guy may use 20Hz as a guide, thus the Impedance is 2*3.14*20*60 = 7.5kohm. Another guy may feel that there’s not much life below 40Hz so he uses 40Hz and arrives at Impedance of 15kohm. Worse still, someone crooked may go for 100Hz and claim Impedance of 37kohm!   So ask at which frequency is the impedance specified? Better still, just ask for the Inductance.

Dating Maggie

Hold on! Hold on! Shown here is just a prototype. We are still a few weeks away from ready to sell. Sit tight boys! She will be ready soon!

Still working out the details, like PRICE, and OPTIONS. Since she takes a godly 30 hours of manual labour to build (she’s a tough one, mate!), it’s no wonder there are sooooooo few such manufacturers in the world. Well, add AudioHobbyist to the list!

For Sale

	USD260 a pair for these babies. Shipping weight about 1.3kg.
	For a limited time only! 24-step switch to go with Maggie. USD18 each.

Wiring up Maggie

They are separated into 4 groups of wires, each with different colour heatshrink.

Alert! Alert!

Get your bib ready!

Fully assembled/tested in chassis, plug and play, ultra cool, autoformer volume control blah blah blah… better known as Maggie Passive Preamp. Call her Maggie TVC Passive Preamp if you wish to.

Isn’t she a beauty? Told you you’ll fall heads over heels over her! Yours for USD400.

There was a problem though. Shipping cost for the above unit was too high. Besides, having the trans inside the chassis yields not only a slimmer chassis, but allow stacking of components too. *hint: monica and charlize in matching chassis*

So this is the new standard version.

	Maggie Autoformer Passive Preamp!

We listened to you and it seems like many of you wish for a Maggie with multiple inputs and a selector switch. We’ll be offering this option soon.

Pride in craftsmanship

As you can see from the chassis above, we take pains to finish it as fine as we could, befitting Maggie’s stature.

Maggie Passive Preamp does not use the above switch but this much better made-in-Japan silver contact switch.

Measurements

Audiohobbyist isn’t afraid to show you some measurements! If you are looking for hard core specs, here’s some to appeal to your ANAL-ytical side. Ha ha!

Freq response

There’s a slight resonance at 70kHz but throughout 5Hz to 30kHz, we are talking about +/-0.5dB variation! +/1dB all the way from 5Hz up to 85kHz!
 Here’s more pics to knock you out!
Maggie’s distortion performance

1Khz THD = 0.025%

10Khz THD = 0.0235%

 Maggie’s inductance is 74 Henries.

When operated at 100Hz, the input impedance is 47kOhm.

At 10kHz, input impedance is 39kOhm.

At 20kHz, input impedance is 19kOhm.

 All these show that if we are driving Maggie with CD player with an output impedance of 600ohm, it’s ‘piece of cake’ to drive the above input impedance.
The last 3 setups above were tested with a dummy load of 4.7Kohm connected at step number 12, which simulates Maggie’s operation turned up to half of the volume. This simulates the load resistance of any amplifier in market, and 4.7Kohm
is the lowest input impedance of amplifiers in the world. We can’t find any amplifier that have lower input impedance than 4.7kOhm, meaning we are testing the worst case scenario here!
 
Take my Money! I want to Buy now!

How are we going to disappoint you? Go to our spanking new e-Store now! http://store.diyparadise.com.
 

diyparadise.com

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