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Tablebeast Modified Akai / Roberts Tube Reel Monoblock Amps
Old 24th June 2012
Here for the gear

Hardware Tablebeast Modified Akai / Roberts Tube Reel Monoblock Amps

You can bid on the auction or just buy directly from me for $899. This is an introductory price for the next 10 units.

Tablebeast Modified Akai / Roberts Tube Reel Monoblock AmpsJENSEN Tablebeast Modified Akai Vintage 2 Channel Tube Mic Pre Amp Preamp DI Mod | eBay

Jensen Akai / Roberts Tube Monoblock Modified Amp

Single Monoblock converted into a 2 channel Microphone Preamplifier - Rack Mount or Tabletop

Tablebeast modified Akai / Roberts TB-2XP1 module. Please note, this 2 channel preamplifier is made using the amplifier electronics from Akai/Roberts Tube Reel to Reel decks. Each module is taken apart completely, parts are refurbished and a whole new circuit with all new wiring and capacitors are built in the donor chassis from the ground up! This is NOT a simple, mod, tweak or recap like you'll find from other sellers. Much like a modern Street Rod car, this is effectively a brand new device made using vintage parts. Find out more details at my DIY project blog, XFMR DIY Projects

This Jensen model has the following options: It has the Jensen XLR Input Package (XLR female jack, JT-115K-ETB input transformer, pad/phase switches) on both channels and Case upgrade. You can choose from a 3U Metal Rack case or wood tabletop case. To be absolutely clear, neither of the items pictured are the exact one you will receive, these pictured items are past devices and simply show you what options are available. These modules are MADE TO ORDER by hand and can take up to 30 days to deliver. I can make yours look just like this one or change up the styling/colors to suit your needs. Also, if you already have one or more of these modules that you want me to modify for you, I offer a $100 trade in credit per module for donor Akai M6, M7, M8 and Roberts 720, 770, 770X, and 997 units sent to me (other units may be compatible, please inquire for details. A maximum of 2 donor amps are accepted per order). The modified 2x Pre chassis, when complete, consists of two discrete all-tube, high voltage audio preamplifier circuits inside. That's right, TWO channels all with their own inputs and outputs in the single monoblock.

The circuits are high gain microphone preamplifier / DIs suitable for use with even low output ribbon mics. Gain is 76+ dB. It uses an EF86 and 12AU7 and has an XLR input with a Jensen transformer and pad/phase switches. It also has a 1/4" DI input and a 1/4" line level input. The output per channel is a transformerless and impedance balanced type on 1/4" TRS jack that is compatible with 1/4" TS and TRS cables. For controls it has a single gain knob! Between the single gain knob and pad switch, it is all the gain control you will need. I have strived to make this design as simple and as pure of tone as possible. It has everything it needs and nothing it doesn't. There is NO phantom power on-board by design to keep it simple. If you need phantom there are plenty of external power supplies available from many places. The design is original and unlike anything else you have used before. It has no negative feedback in the circuit and this makes it behave in different ways depending simply on where you have the volume knob set. It can be very non-linear and when cranked with a tremendous soundstage that compresses ever so lightly, much like hitting tape. It also stays huge with tons of headroom when used on more sane settings!

The amp's insides were completely disassembled, assessed, redesigned and replaced where needed from the ground up. All the good parts with mojo were tested, refurbished and rearranged. However, the wiring, electrolytic caps, and many other critical parts are all new, fresh stock. The resulting amp is the best of both world's: a unique, vintage-sounding preamp but with absolutely no old-amp gremlins! The preamp channels have a shared tube rectified power supply featuring a single 6X4. It comes complete with a set of tubes and is plug and play. Just add some mics! You also get a 1 year warranty on the mod and lifetime support beyond that.

I can paint the faceplate any color you like, or just leave it the way it comes from Akai. I can also offer cases in black or the pictured silver as well as several knob options. I build custom gear tailored to the individual so you tell me how you want it served up! This deluxe model has all my standard options and the input transformers used are Jensen, but I can install just about any iron that will fit. I can even add output transformers with XLR male jacks if desired. Please inquire about these color and transformer options. Also, the meter on the faceplate is from the donor amp. It is made for speaker-level signals and is non-functional. I include the meter simply for aesthetic purposes, but can install a block-off plate instead if you prefer. I can also install a functional aftermarket meter with a switch to select the active channel can be added, but that is an extra expense because of the added parts cost. An optional output transformer can also be added for an additional cost.
Attached Thumbnails
Tablebeast Modified Akai / Roberts Tube Reel Monoblock Amps-2xprewoodshure103.jpg   Tablebeast Modified Akai / Roberts Tube Reel Monoblock Amps-2xprewoodshure104.jpg   Tablebeast Modified Akai / Roberts Tube Reel Monoblock Amps-bruteforceedit1.jpg   Tablebeast Modified Akai / Roberts Tube Reel Monoblock Amps-img_1622.jpg   Tablebeast Modified Akai / Roberts Tube Reel Monoblock Amps-img_1598.jpg  

Tablebeast Modified Akai / Roberts Tube Reel Monoblock Amps-img_1592.jpg   Tablebeast Modified Akai / Roberts Tube Reel Monoblock Amps-img_1552.jpg   Tablebeast Modified Akai / Roberts Tube Reel Monoblock Amps-img_1586.jpg   Tablebeast Modified Akai / Roberts Tube Reel Monoblock Amps-img_1559.jpg   Tablebeast Modified Akai / Roberts Tube Reel Monoblock Amps-img_1542.jpg  

Old 25th June 2012
these look seriously cool...are both channels the same?
Old 25th June 2012
Here for the gear

Funny you should ask about both channels being the same. On this 2xPre unit, yes they are the same circuit x2 in the one monoblock. I also do the same pair of identical circuits inside the Ampex 600 and 601 series, but those cost a little bit more based on the more expensive donor amps.

I DO have another design that I call my Pre+Amp that has a single preamp circuit from this design, but instead of another preamp circuit there is a low-watt instrument recording amp. It has hi-z input and 8 ohm speaker output with built in dummy load, but the amp can also be used as a line level fx unit with an additional padded line input and padded phones/line output. All together the Pre+Amp is a totally different animal than the 2xPre, think of it more like a modular amp because you can go and patch the two circuits together in any number of ways.

You can inquire directly to me at [email protected]
Old 1st July 2012
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If anyone has any of these Akai / Roberts monoblock amps that they want modified I can do all kinds of things with these guys as a modding platform. I've done preamps, amps, hybrid setup, compressors, fx units, and even synth modules. Your imagination is the limit with these guys.
Old 4th July 2012
Gear Nut

what do these sound like?
Old 4th July 2012
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I am working on recording some dedicated samples soon. All the stuff I currently have is from unfinished projects I own no rights to and can't show yet. Excuses aside, I will have extensive sounds soon. That will ultimately answer your question with sound.

If I could attempt to describe how this circuit sounds with words, I would say first that this preamp has a unique sound that is unlike anything else out there. I built it to be a no frills, pentode preamp, no feedback circuit. This gives the sound more character and a less linear response. That means the tone changes as the gain is increased. In practice that means every source has a distinct sweet spot where it just opens up and comes alive. From that point you can dial back to make it sound a bit smaller or crank it further to put a little hair on it. But, since it is a true high voltage device with actual audio tubes (instead of the standard 12AX7) it has lots of headroom AND lots of gain. And even when you do drive it, it will then compress lightly much in the same way tape does. The noise floor is low and the bass response is excellent. I like to think of the sound as somewhere between a REDD47 and a Altec 1566. If that sounds like a broad spectrum of sound, that is because this preamp has a very wide tonal palate. Now most of that tonal change is the result of the preamp stage. This unit also has line inputs that bypass the preamp stage and feed the line stage directly. This line stage is nice to insert across a DAW buss to just smooth everything out and make it gel. It is very clean, with even more headroom than the preamp stage and this is especially where I like the transformerless outputs the best. Just pure tubes across the bus with no iron in between will really surprise you with how amazing it sounds.

This circuit is an original design somewhat based on the original EF86 tape head circuit of the Akai monoblock donor amp. I tweaked and adapted it to a 12AU7 line amp set up as a white cathode follower. This allows for a transformerless output that is 100% compatible with modern recording equipment. The line amp has about a 3k output impedance, so modern stuff like DAW converters, which are 10k+ input impedance love it. Of course if you want an output transformer for long runs, dual outputs, coloration, or just to interface with vintage tube equipment that demands a 600 ohm input, I can add them as well.
Old 8th July 2012
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I have a unit with Jensen input transformers up on ebay right now: Tablebeast Modified Akai / Roberts Tube Reel Monoblock AmpsJENSEN Tablebeast Modified Akai Vintage 2 Channel Tube Mic Pre Amp Preamp DI Mod | eBay
Old 12th July 2012
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Here are some sounds from my similar unit the Pre+Amp. It has the same preamp circuit along with a low watt instrument amp next to it instead of two preamp channels. The vocals on the second and third tracks use this preamp circuit. Here are the samples: XFMR DIY Projects: Pre+Amp Sound Samples 1
Old 19th July 2012
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More sound samples coming soon. Thanks for all the PM compliments, dont forget to check out my blog with details on the the how and why of my mods. It is at XFMR DIY Projects
Old 19th July 2012
Lives for gear
d1rtynyc's Avatar

I threw away one of those exact Akai R2R's back when I moved to LA in 2001. Man do I regret that move. I found it in the trash initially so easy come easy go.
Ahh the folly youth.

To the OP..... Really nice work. Looks cool.
Old 19th July 2012
Here for the gear

I threw away one of those exact Akai R2R's back when I moved to LA in 2001. Man do I regret that move. I found it in the trash initially so easy come easy go.
Ahh the folly youth.
Its OK, they are rather common. Someone else probably grabbed it anyway! They really are just ordinary devices as tape machines, but their power and output transformers have SO much more potential in them in the right circuit. That is why I concentrated my efforts on using these as a modification platform. In addition to the awesome parts that I reuse, there is so much space in these chassis to add additional transformers and build just about anything I want. Plus, when they are done they actually look like they were built like that originally! That is part of why I don't use any modern tech like phantom power or relay switching in my designs. I want them to be devices that would have been possible when these units were originally built.
Old 15th August 2012
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I am recording some new samples with a Jensen equipped unit this week. If anyone has any specific requests for sources for me to record samples of, let me know!
Old 24th August 2012
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Here are some samples I recorded while some friends jammed. My engineering chops are super rusty, got to get back at it more and I will get better samples, but for now these sounds pretty good.

Tablebeast Akai Roberts Modification Sound Samples Raw by XFMR on SoundCloud - Create, record and share your sounds for free
Old 14th January 2013
Here for the gear

I have been cranking these out lately! I had to turn some orders away last year while I caught up, but I am now taking orders once again. SO, if you got left out before, get on board now while you can!
Old 18th March 2013
Lives for gear
I've been considering sending my Casio SK-1 to Tablebeast for modifications. I know he modded Trent Reznor's SK-1 a while back, but is he still taking orders?
Old 24th March 2013
Lives for gear
schmuck's Avatar
Has anybody used one of these amps? or maybe the ampex ones? Really curious to hear some user feedback as the units look very interesting.
Old 16th March 2014
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Leraven's Avatar

I've got an Akai M-7 in great shape that I need to get rid of. Both channels work great. I don't have the time/money to convert, so anybody that is interested PM me! I'm in the DFW area.
Old 31st July 2015
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beware giving jesse at tablebeast any money. He has had 1500 dollars of mine for two years and still no product. My friend has given him over 3000 pounds sterling and has had nothing for 3 years. Be careful, he is a crook
Old 22nd September 2015
Lives for gear

Sorry to hear about that.

This looks like something that shouldn't have been here at all, even if legit... since it's more of a one-off custom mod thing.
Old 13th November 2015
Here for the gear
Beware of Tablebeast (Jesse Mesa-Savage). He has had my Ampex 601 preamp that he was making into a DI/preamp voiced for a piezo string bass. He has had my gear for about eighteen months. He has changed his email address and he rarely responds to emails. When he does its full of excuses and he has never sent pictures to prove work is being accomplished despite numerous requests. I've requested he return the project parts or finish.
Old 13th November 2015
Lives for gear
schmuck's Avatar
Hope you guys can sort it out. Maybe you can reach Jesse via PMs, it seems he is still on GS once in a while.

To be fair, a few years ago he *did* deliver a converted amp to me, and it works very well to this day. I'm aware that doesn't help the people who have paid and not received anything, but at least it means that he actually has the abilities to make the stuff. I don't know what his life circumstances are and people can obviously also change. Again, good luck to all, really wish you find a proper (and hopefully peaceful) way to sort this out once and for all.
Old 10th October 2019
Here for the gear
New update. It’s now October 2019 and my Ampex 601 mod as noted above, that included my provided chassis and a Triad transformer and partial payment still has not been delivered. I’ve given up and except the loss.
Old 2 weeks ago
Lives for gear
I sent that POS Tablebeast an SK-1 back in 2014 for modification and never got it back or heard a reply. I wish all the misery in the world upon him.
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