Showing posts with label Dave Slagle. Show all posts
Showing posts with label Dave Slagle. Show all posts

Saturday, January 28, 2017

Intact Audio New Autoformers Now Available

I am a big fan of autoformer volume controls and have been listening to the ones from Intact Audio for many years. Screw pots is all I gotta say.  Dave Slagle's AVC products are available in many configurations and also custom work is available. 
What do you want from an autoformer? I can safely say you can find it at Intact Audio. Lets look at a few of what is available today. 
The top of the line is a 47 position stereo attenuator that goes seamlessly from +5dB to -51.25dB in 47 1.25dB steps. This stereo unit can also be wired as a mono balanced unit. It is also available in silver if that is your fetish.
 I know I'll be picking up one of these at some point for a DHT preamp. Two of the 23 position autoformers are placed on a single board with a "penalty free" balance control between them. Each autoformer step is 2.5dB and the balance control allows for a 1.25dB shift to the left or right. Maximum attenuation is 52.5dB.

This is what I'll be installing in my Brook 12A monoblocks I'm working on. This is a compact 23 step autoformer. I'm going with the stock attenuation with the following steps 0, -3, -6, -9, -12, -14, -16, -18, -20, -22, -24, -26, -28, -30, -32, -34, -36, -39, -42, -45, -48, -52 and Mute. Since this is Intact Audio Dave will wind any taper desired
  
 

Monday, December 14, 2015

Voigt 4ft Tractrix Horn

People talk of Western Electric being rare but no these 4ft Voigt Tractrix horns are extremely rare. Likely only a handful of the big fellas exist. I only see ads of people looking for them and a few pictures of them on the internet. These look incredible.  


I would like to try this approach some day. This reminds me of what Dave Slagle of Intact Audio does with Lowther drivers and big round Le Cleach horns.
 

Sunday, June 29, 2014

Slagle Autoformer Volume Control Modules And My First DIY

This is my first completed DIY project #I01 or I owe one. A while back I found a 1930's Phillips battery box and had refinished it for some project in the future. Ok I knew what I wanted it for as I was already a Slagle AVC fan. There are no power supplies or resistive parts which made it a good first project. Dave Slagle has cured me forever wanting or needing a traditional preamp. The AVC has been one of the biggest improvements I've made to my system.
I really dig the 80 years of attitude the box has picked up and glad it still shows. Problem is now I want to use this look again but I need bigger boxes for amp building.
 
This is the best shot I got of the  Slagle autoformer modules as I wanted to get them loaded ASAP.
These Autoformer modules operate in a slightly different manner than traditional linearly switched volume controls. Rather than using a single switch, two discrete switches are used to control the level. The switch on the left has 12 posiitons that are in 3.75dB increments. The switch on the right has 3 positions allowing +1.25dB, 0dB and -1.25dB modification of the overall level. By using this dual switch arrangement 1.25dB steps are possible. The total attenuation range goes from +1.25dB to -41.25 dB in 32 steps. The nature of the device skips the -3.75dB tap so the steps are +1.25, 0, -1.25, -2.5, -5, -6.25, -7.5...1.25db steps to -41.25 and off.

Q - Why use an autoformer volume control? I've been happy with a good quality potentiometer.
A - The simple answer is that most people find that the autoformer volume control sounds significantly better than even the best potentiometer or stepped attenuator. And it's not a subtle difference; most people report that the autoformer has such an open, effortless sound that they would not consider going back to a resistive device.
Exactly why they sound better is still under debate, but one theory is that it's because an autoformer doesn't attenuate by wasting energy. A fairly good analogy can be made to the transmission in a car. If you need to drive at a slow steady speed which method would you choose: (1) leave the transmission in high gear and apply the brakes to keep from going too fast, or (2) downshift into a lower gear that will allow the car to go the desired speed with minimum effort?
An autoformer is essentially an electronic gearbox that operates without wasting significant energy. Potentiometers and stepped attenuators adjust the signal level by literally turning the excess signal into heat. On the other hand, when an autoformer is adjusted for low volume level it actually makes things easier for the source, much like a low gear makes things easy for your car engine.
It becomes quickly apparent that the reflective load can be ignored in this case since it is many multiples of the inductance in parallel with it. Inductance gives you a impedance = 2*pi*Frequncy*L(inductance) or Z=2piFL. Its this simple formula that tells you what you need to know about the impedance presented ot the source.


Here you can see the acid burns from the old batteries that leaked  in the box. This was before and after wiring these up with magnet wire. I think the green wire sounds best ;-). Fortunately Dave's modules makes them very easy to install so even I couldn't screw it up.
 
Here are the left and right sides. 
 I tried many different new knobs on this box but they just didn't look right. After purchasing the wrong sized vintage knobs three times I finally got these and pulled the big selector from a Bud national radio I had. Lesson learned vintage box gets vintage knobs. 

There will be no labels. Perhaps that will keep party guests off my knobs.
Thank you Dave Slagle aka Intact Audio.

Wednesday, May 21, 2014

Weekend Hanging Out With Experience Music And Intact Audio And WE16 Part IV

I first saw the Western Electric 16A at the Klipsch Audio History Museum in Hope, AR in 2003. It was love at first site. I never thought I would get to hear one until this one landed in upstate New York. 
   
Not only did I get to hear a 16A but I got to here it with early WE555 field coil drivers.
This field coil power supply uses the mighty Western Electric Mercury and Argon rectifiers.
   
 Look at how clean the lines are on this horn. Just beautiful.


This 16A was powered by the 2 watt amp on the right.  Great sounding little amp.
So how did it sound?  I'm not great at describing sound and I hate reading descriptions of how things "sound" but I'll give it a shot.

Ok so here is a speaker I have wanted to hear for over 10 years. I've built up an ideal in my head I'm pretty sure it can't live up to or at least this was my concern.
I awoke got up and went for a brief morning walk and came back to grab some coffee. After grabbing some coffee  I heard sound coming from the other room which had to be the 16A. I think it took me 2 seconds to find my seat in front of the 16A. This speaker met and exceeded my expectations quickly. I was speechless. It had an energy that was very nice. I was unfamiliar with the first African artist we listen to but it was very good.  We also listen to some early jazz for example Louis Armstorng and Ella. The energy was  perfect.

I don't know the specs nor do I care right now. This sounded incredible. When listening to vintage speakers I have been greatly rewarded by stepping out of the 20hz to 20khz box. It is such a small place.

This concludes the IV part post of hanging with EMIA. It was superb.

Thank you Jeffrey, Lisa, and Dave. Your hospitality and generosity was greatly appreciated.


Monday, May 19, 2014

Weekend Hanging Out With Experience Music And Intact Audio Part III

The tag line of the Experience Music and Intact Audio blog Hi-Fi Heroin is new school ideas meet old school junk. The junk they refer to is far from it. However It is very clear after just walking around snapping a few pics who they study and revere.
I was supposed to do a video interview while there but time just slipped away. Maybe next time. I learned alot just from hanging out and listening.  

 These petal horn studies are reminiscent of the early audio horns. I got to hear one of these briefly and it sounded great.
The picture of this horn does not do it justice. This walnut is stunning. I hope to see more of these in the future. The construction was very interesting. 

Expect big things from EMIA in the future.


Wednesday, May 14, 2014

Weekend Hanging Out With Experience Music And Intact Audio Part II

Nothing.... Nothing beats a large well designed horn system.
 I love the size and scale of this system. You can't fight physics horns just have to be big. The sound of this system was true to source, imaged beautifully, and had that extraction of detail I love. I got to hear this system a little louder than on previous visits which was a treat.
When I heard Junior Marvin's Police And Thieves and Roots Train on this system I was floored. This album was produced by Lee Scratch Perry so quality was very high from cymbals to vocals to thick bass. All the tracks we went through on this system were incredible. Jeffrey also played me some very early Phish that was extremely innovative so I am going to find that album. I didn't think I was a Phish fan well now I am.
 
Here is Stacey modeling the horns. She is 6ft tall so that gives you a good idea of scale.
 
 
If you have known Jeffrey and Dave for very long you realize they are nocturnal music listeners. Now when I think of the Eimac 75TL amplifiers it is glowing tubes in the dark that come to mind. 
 When I look around at all the gear I notice all the equipment in the house is chock full of custom wound Slagle transformers, autoformers, and chokes. That is alot of winding. Dave and Jeffrey are a great team and build stunning gear. The fact that they are founding members of the no bling coalition is an added bonus. The only shine you'll find is from glowing tubes.   
Eimac 75tl output stage
 
 Western Electric 287A mercury thyratron rectification
 Can't believe I didn't get better pics of the 75TL or the EMIA AVC with remote volume control or the phono stage.... WTF... I guess I was just enjoying the music.

This pic is from my GoPro camera which isn't great close up as it distorts but here it is anyway. 

The EMIA guys are too humble to say it so I will. 
If you need custom audio I can say with 100% confidence that Jeffrey Jackson and Dave Slagle are among the best. I've heard their horn systems, WE field coils with their supplies, phono stages, preamps, and they are all top notch. Guess I'm a junkie too.