Tube and Solid State Preamp, Amp, FX, and Instrument Projects for the xfmr.org Radio Station.
Saturday, October 6, 2012
Metasonix Wretch Machine S-1000 TUBE Synthesizer
Metasonix S-1000, the Wretch Machine:
For the longest time I have been focused solely on recording equipment with my tube projects. I used to really be into weird synthesizers back in my circuitbending days. My interest in synthesizers has been piqued lately so now I have come full circle back to them. This time of course I want to make them all out of tubes! This Metasonix Wretch Machine is made out of an awful lot of tubes, that is for sure! I opened the case up just to see what is going on under the hood and I saw not only tubes, but a few solid state bits in there as well. Based on Eric Barbour's DIY projects on Ken Stone's analog DIY synth site I can guess what is going on in there.
Where my designs will differ from these current Metasonix ones is that I will be using true all-tube designs. NO solid state anything in my planned designs! From the tube rectifier, to tube VCA, tube LFO, tube VCO, tube PWM, etc they will stay purely thermionic! I will start with some older TS series Metasonix circuits and tweak them to fit into my Akai/Roberts donor chassis. Anyway, here is the S-100 I currently have to mess around with. Unfortunately I have to sell it, but it will be replaced with my very own modular tube synth based on similar circuits.
By the way, these circuits run on Hz/v CV so I am looking for a Yamaha CS5, CS10, or CS15 to use as a controller. Let me know if you have one of these beasts at a reasonable price. Even if it is broken I can probably fix it.
This is a jam that a friend of mine did using the Wretch for the very first time:
Thursday, September 20, 2012
New Akai Roberts Tube Mod Stuff from August 2012
I have been tearing through my waiting list and trying to get to zero so I can begin the studio gear in earnest. I haven't had much time to update the blog here in a bit. I do have some new pics taken by my friend Patrick Olin. So, for now, enjoy.
Tablebeast TB-PPA1 Pre+Amp, front 3/4 view:
Tablebeast TB-PPA1 Pre+Amp, rear view:
Tablebeast TB-PPA1 Pre+Amp, bottom view:
Tablebeast TB-PPA1 Pre+Amp, bottom 3/4 view:
Tablebeast TB-2XP1 2x Preamp, front 3/4 view:
Tablebeast TB-2XP1 2x Preamp, rear 3/4 view:
Tablebeast TB-PLX1 Plexi8, front 3/4 view:

Tablebeast TB-PLX1 Plexi8, rear 3/4 view:
Tablebeast TB-2XP1 2x Preamp, front 3/4 view:
Tablebeast TB-2XP1 2x Preamp, rear 3/4 view:
Tablebeast TB-PPA1 Pre+Amp AND TB-PLX1 Plexi8 in wood case, case closed front 3/4 view:
Tablebeast TB-PLX1 Plexi8, front 3/4 view:
Tablebeast TB-PLX1 Plexi8, rear 3/4 view:
So here they are, my most recent Akai Roberts Tube monoblock conversions from August. Please leave comments here and I will try to reply to all of them.
Tablebeast TB-PPA1 Pre+Amp, front 3/4 view:
Tablebeast TB-PPA1 Pre+Amp, rear view:
Tablebeast TB-PPA1 Pre+Amp, bottom view:
Tablebeast TB-PPA1 Pre+Amp, bottom 3/4 view:
Tablebeast TB-2XP1 2x Preamp, front 3/4 view:
Tablebeast TB-2XP1 2x Preamp, rear 3/4 view:
Tablebeast TB-PLX1 Plexi8, front 3/4 view:

Tablebeast TB-PLX1 Plexi8, rear 3/4 view:
Tablebeast TB-2XP1 2x Preamp, front 3/4 view:
Tablebeast TB-2XP1 2x Preamp, rear 3/4 view:
Tablebeast TB-PPA1 Pre+Amp AND TB-PLX1 Plexi8 in wood case, case open front 3/4 view:
Tablebeast TB-PPA1 Pre+Amp AND TB-PLX1 Plexi8 in one-of-a-kind case, rear 3/4 view:
Tablebeast TB-PLX1 Plexi8, front 3/4 view:
Tablebeast TB-PLX1 Plexi8, rear 3/4 view:
So here they are, my most recent Akai Roberts Tube monoblock conversions from August. Please leave comments here and I will try to reply to all of them.
Monday, August 27, 2012
Akai Roberts 2xPre, Plexi8 and Pre+Amp Mods Live Tracking Samples
Here are some live tracking samples. A few friends were jamming while I was finishing up some mods so I just threw up some mics. Very loose recording as a result of course, but it will show you various tones you can get with this stuff. There is no editing, effects, or any kind of manipulation whatsoever on these tracks. Faders were set to zero and elements hard panned. That's it, there aren't even fade ins or outs. Track description tells you what the elements are and how they were tracked.
Ampex 601 and a Pair of 602 Reel to Reel Tube Amplifiers
Ampex 601 and 2x Ampex 602:
I just got a fantastic score of fleabay yesterday. It was a lot of three Ampex reel to reel tube amplifiers. One is a 601 unit and the other two are 602 units. The 602 pair both have their stock input and output transformers installed in place, but the 601 is missing its plug-in input transformer. I really like both of these units. The 601 has a tube rectified power supply for high voltage and will have an artificially center tapped AC source for the 6.3v heaters. Nothing wrong with AC heaters is you do them right to cancel out the hum. The 602 has a power supply is completely different from the 601. It uses a solid state rectified voltage doubler circuit for high voltage and a solid state rectified DC for the heaters. I usually tune it to be slightly cold at around 6 volts. The sounds of the two units are slightly different despite having identical audio circuits. Because of the tube PSU the 601 has a softer edge and feels silkier overall. The 602 with its solid state PSU has slightly more gain + headroom and is tighter overall. It is a little more aggressive and gives up the softer edges of the 601. It is an interesting trade-off and I like to have both on hand for the different sounds. I have used them interchangeably on just about any source and it really just comes down to personal taste.
My plans are to make each unit a two channel microphone preamp with XLR microphone and 1/4" DI inputs as well as dual outputs: one will be transformer balanced on an XLR jack and the other will be impedance balanced on a 1/4" TRS jack. One of the 602 units will get the stock input and output transformers from both 602s while the other 602 and the 601 will get Jensen input and output transformers throughout. All three will be put up for sale to raise funds for the station. If you are interested please inquire for pricing and availability.
Monday, August 20, 2012
Yamaha PM1000 Recap Mod Kit Installation Standard and Deluxe
Here are some time lapse videos showing the installation of both the standard and deluxe kits.
Standard Yamaha PM1000 Recap/EQ Mod Kit Install:
In this first video you can see me removing the old caps and installing fresh Wima films to replace the tantalum caps for coupling/high pass and the poly caps with updated values for EQ. I am alos replacing all the electrolytic with Nichicon Audio series in much higher values. I also replace the old crappy ceramic caps with modern MLCC types. This gives better tone and a broader frequency response.
Deluxe Yamaha PM1000 Recap/EQ Mod Kit Install:
The deluxe kit is the same as the standard kit, except it takes about 60% longer to install and that is because include film bypass caps across all the electrolytics on the screenprinted circuit board side.
Standard Yamaha PM1000 Recap/EQ Mod Kit Install:
In this first video you can see me removing the old caps and installing fresh Wima films to replace the tantalum caps for coupling/high pass and the poly caps with updated values for EQ. I am alos replacing all the electrolytic with Nichicon Audio series in much higher values. I also replace the old crappy ceramic caps with modern MLCC types. This gives better tone and a broader frequency response.
Deluxe Yamaha PM1000 Recap/EQ Mod Kit Install:
The deluxe kit is the same as the standard kit, except it takes about 60% longer to install and that is because include film bypass caps across all the electrolytics on the screenprinted circuit board side.
Tuesday, August 14, 2012
Getting the Kickstarter Campaign Distilled to Perfection
No post in a little while here. I don't want anyone to think I'm running out of steam or losing interest. Far from it! I have been hip deep in plans for an upcoming Kickstarter campaign, plus I am working down the very last of my waiting list and trying to 'get to zero' where I have filled all current orders so I can begin building my rig. I should be there this week. And the Kickstarter campaign should be ready to launch once I get the video finished. I've got just about everything else ready to go! [The hardest thing is to distill the hundreds of ideas I have for the station/label down to the basics and then find a way to explain it properly to people. Since it is not really a radio station or a record label and it is non-profit, but takes no funds from the government it has been difficult to figure out how to present it. I'm getting there. Still it is lots and lots of work for no money, but man will it be cool once I get this thing off the ground! In the mean time if anyone wants to help out the cause by having me convert one of your Akai, Magnecord or Ampex tube monoblocks I sure could use some funds to get this ball rolling!
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