Tons of New Designs Brewing

Don't worry, folks! I may have recently moved to the very edge of the Green River Gorge, but I have not yet fallen off the face of the Earth. I have so much new stuff that I have been brewing that I just can't WAIT to share it with all of you. New Akai / Roberts, Magnecord, Tape Delay (Ampro and Webcor) designs are simmering while I close out my waiting list for 2012. Look for some BIG moves come January! Pictures? Well,  I do have pictures of my new place and my new tractor, er... truck.

Webcor Tube Reel to Reel into DIY Tape Delay Echo

Webcor Royalite model 2001-1C All Tube Reel to Reel:

I just bought this lovely mono, tube powered reel to reel off of an auction site. I saw a video on youtube where someone made a crude version of a tape delay with a similar deck. For my version I have some more detailed and involved plans to completely transform this unit into a full fledged tape delay with adjustable tape speed, microphone input (with transformer), preamp, simple mixer, and power section that drives a speaker. So, it will be a colored microphone preamp and low watt guitar amp in addition to being a tape delay! I am even working out how to modify the original little crystal mic to fit on a standard mic stand clip by adding a handle. I have two of these Webcor mics headed my way, so I may just wire them in series and or parallel as some kind of double-element mic. Of course this would be a very colored mic, but so is the preamp! Here is the original schematic.

Thanks to Dr. Zee of http://www.mzenertainment.com for scanning this schematic. Be sure to check out his site. If you like what I am doing here on this blog you'll love the amazing projects he has built for his own studio. I am really impressed and hope to get XFMR to that point soon.

Looking over this schematic, this unit is ripe for modification. All the tubes are driven by the power transformer, so no weird AC doubling circuit for power tube B+ like found in the Wollensak T-1500 units. The motor is an AC type and not a good candidate for adjustable speed, so right there I will have to start looking for a DC motor to replace it. My first order of business is to examine the schematics of dedicated tube tape delays like the Gibson Echoplex EP1 and EP2 to see what parts of this circuit I can toss. First thing to go is all the switching. The modified unit will have two modes: tape spinning as a delay and tape not spinning as a straight up amplifier. I will have a dedicated toggle switch that cuts the motor on and off and another toggle with a footswitch in parallel that mutes the delay circuit.

In my plans I would like to have just one extra playback head. No need for multitaps as that just gets more complicated. For controls I will keep it simple: preamp gain, feedback amount, dry level, wet level and of course a tape speed control. There will also be a 1/4" footswitch jack to round out the controls. I/O will include an XLR input with pad and phase switch, a Hi-Z input, speaker-level 8 ohm output, and a line level output. It has a built-in speaker, but I will have a switch that switches this to a dummy load when necessary. The reason for the XLR input is that this unit will be made for vocals in addition to instruments, so I figured if I remove the counting mechanism I will have plenty of room on the face for the female XLR jack.

Here are some additional pictures of the donor unit and a few other parts units that I bought mostly for their Webcor heads, but I am sure I will find other parts to vulture for this and the next unit. I am planning on building two of these: one for my good friend and patron Damiam Asker and one for the XFMR studio collection.

 

Webcor Regent model EP2006-1A:

This model is very similar to my main EP2001-1C unit and will make a fantastic parts donor.

Webcor Regent model GP2910-1

This last model has vastly different guts, thought it looks similar from the outside. It should still yield many great parts for this pair of mods.

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:

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-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.

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.