Thanks X! Seems to be easy enough to solder onto to the experiment boards. I got the gerbers from puijkh and the boards are in fab as I type. Thank you puijkh for those!
Question about the B1 build before I embark though. I built the Yarra as cap-coupled. The B1 Buffer Rev 2 is a DC coupled circuit. Any reason to change anything on a Yarra end? I'd rather not make any changes to the caps on the Yarra board if I don't absolutely have to.
Question about the B1 build before I embark though. I built the Yarra as cap-coupled. The B1 Buffer Rev 2 is a DC coupled circuit. Any reason to change anything on a Yarra end? I'd rather not make any changes to the caps on the Yarra board if I don't absolutely have to.
I didn’t know what a Slagle AVC was so looked it up. It’s basically a 7 position transformer based attenuator.
I have not tried it but 7 steps of attenuation seems limiting. Some people really like the sound signature of an auto former in the signal path (look at how fans of the M2 amp and its variants love what it does). What it does is introduce a bit of added third harmonic distortion and some second harmonic distortion so that may give the sound some extra “bite” and warmth. It may help with reducing ground loops since it is transformer coupled. But I am not sure for neutrality, it will be better than a good resistive pot or stepped attenuator.
I have not tried it but 7 steps of attenuation seems limiting. Some people really like the sound signature of an auto former in the signal path (look at how fans of the M2 amp and its variants love what it does). What it does is introduce a bit of added third harmonic distortion and some second harmonic distortion so that may give the sound some extra “bite” and warmth. It may help with reducing ground loops since it is transformer coupled. But I am not sure for neutrality, it will be better than a good resistive pot or stepped attenuator.
X,
The most up to date info on the Slagle AVC is on the Intact Audio website which is Dave Slagle’s company. This autoformer based attenuator is now considerably upgraded with multiple positions and various cost offerings depending on whether you go for copper or silver wire.
Look at the Elma 47 position version: https://intactaudio.com/atten.html
I built a fully autoformer based balanced volume control a long time back, see here for the Poseidon’s Voice Lazarus
Measurements are actually quite excellent, I had mine professionally measured here.
The Slagle AVC preamp was the most neutral I ever owned until I built myself a computer server and started doing attenuation digitally through HQPlayer and the integrated 64bit volume control. That being said, the differences were quite small but the digital method was cheaper in some respects (hard to compare since the server cost about $2K in parts to build).
Best,
Anand.
Hi Anand,
Thanks for the link and the new top of the line one with +5dB to -51dB in 47 steps certainly sounds like a nice product. Passive +5dB is hard to come by otherwise. Having your own impressions and measurements to back it up is also reassuring. This looks like a great product.
Thanks.
Thanks for the link and the new top of the line one with +5dB to -51dB in 47 steps certainly sounds like a nice product. Passive +5dB is hard to come by otherwise. Having your own impressions and measurements to back it up is also reassuring. This looks like a great product.
Thanks.
I found the horizontal ones (like the drawing you posted), but not the vertical ones as shown in the picture. I was looking in your store on Etsy, maybe that isn't the correct one.
The Vampire vertical jacks appear to have their corner pins on opposite corners to the Elecaudio connectors, which probably explains why your boards have corner holes on all corners, not just 2 of them. For my initial footprint made from measuring (poorly), I used 5.08mm spacing for the corner pins in Eagle with the pins at -5.08, 5.08 and 5.08, -5.08. The Vampire jacks fit with force, but interfere on the inside of the pins. Hopefully going to 5.05 spacing as shown will alleviate that. The 1mm holes for the center pins were tight as well, so I think I will use 2.1mm for the corner pins, and 1.1mm for the center pins.
For vertical mount you pull the pins out with needle nose pliers and install them in appropriate sockets. Straighten the 90 deg bend in the two signal leads. The unit works for both orientations. The ones I stock happened to be setup for 90deg orientation from the factory as those are the most popular for most of my designs anyhow.
Hi X and other builders, I was spending some late hours working on the Yarra MB and schematic. I am a bit confused by X101 thru X108 and X112 thru X115 labelled 12HP059 red and black. I know they have something to do with the rca connectors, but what are they exactly: cables, wires, inside part of rca ... 
Thanks for the help
Thanks for the help