Tapesonic 70-T capstan motor
Comments
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Hello,
I've overhauled the bias oscillator board and one of the playback amplifier boards. I completely removed all of the components and replaced the carbon composition resistors with Dale 1% metal films, the electrolytic capacitors and other capacitor types were replaced with Panasonic film types. I even was able to replace the original transistors with new ones, I matched the Hfe of the two used in the push pull oscillator circuit. All of the metal parts cleaned up nicely. The second photo from the left is the original board.
Cheers, Ken -
I've gone a little crazy on this project. First I decided to get rid of all the old coaxial cable that was connecting all of the circuit boards to the control knobs and mic and headphone jacks with Cardas litz wire, not an easy task. While I was doing this I decided to replace all of the edge card connectors with new, so every circuit board connection had to be written down so I could remember where everything went.
Then I decided this was a good test platform to try and add a "super-regulator" to the power supply. This is way to achieve the lowest impedance (especially at higher frequencies) quietest supply voltage for any audio design. I went with the circuit board designed by Swedish Sjostrom Audio, a beautifully made four layer board that has gold plated solder pads and can be configured to several different reference devices and voltage settings.
I sourced all of the necessary parts using thin film resistors for low noise. I connected it to the rectification part of the Tapesonic electronics and got +24VDC on the nose. Now I can build the Sjostrom rectifier board and test the complete new power supply.
Cheers, Ken
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Hey Ken, nice to find someone else with this deck! Fantastic job BTW. I've been poking around at mine for the last several years. Looking to restore as well. Wondered if I could get a good scan of your schematics as I'll be re-caping the cards and running into trouble on some odd values. I can PayPal you a few bucks for your trouble. Also could probably use some tips about components and such.
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Hi,
Great knowing someone else is interested in the Tapesonic. Here is an updated photo showing the Sjostrom super-regulator installed. I went over the complete chassis inside and out with Q-tips and Flitz getting everything as nice as I could, now I wear white gloves to avoid fingerprints. I installed an IEC type connector, got the transformer mounted (I had to carefully file three of the lamination bolts to get them out of the way for the mounting screws to fit. I also went to shielded twisted pair cables for all of the AC connections running to other circuit points, these are dressed to the left.
Absolutely no problem on the circuit schematics, how would you like them, I can mail you copies or try and photo them. My wife could probably set them up as an email.
No charge, got to support the effort!
Cheers, Ken
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Life saver! Mailing a physical copy would be awesome, but too much trouble. Why don't you just e-mail a scan. Whatever format (PDF, jpeg.....). superdave_2818@yahoo.com. Until then, a quick question. Signal from the mic input runs through a cap before the first gain stage. What is the value? What did you replace the old lytic with? Thanks.
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Or, you could just copy your layout and what components you used?
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No problem, it's a .27uF and I haven't done the record boards yet, just the playbacks and the bias, but I would use Panasonic film types.
I'll ask my wife to do that and I have the original owner's manual I can send, if you'd like. -
Mine have the same cap for playback as well. Pb head signal hits it. I pulled out a 6.4uf 25v lytic out of mine. Strange because this cap and value never seemed to exist! Lol! I replaced it with the closest value I can find: a 6.8uf. This cap is also used in the circuit elsewhere and may explain why I'm now getting distorted audio? Owners Manual would be great as well! Thanks!
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I looked on the record boards and C4 (I took a photo of the board and identified each component so I could figure out where everything went after cleaning) is a .22uF made by the "JOHN E FAST" capacitor company.
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Oh sorry. You are correct. My mistake. Just looked at it.
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That's a great name for a capacitor company JOHN E FAST, too much!
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Lol! Well I'll probably keep those in and maybe get rid of the carbon resistors and replace the filters in the PS. However, I love what you did with the power supply!
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Thanks, that's a design based on the Walt Jung super-regulator power supply updated with a few new ideas. It's found used in some high end digital converters, I'm thinking it will be the first time someone's used it in an open reel tape deck. Ultra low noise and low source impedance at all frequencies.
I'm getting rid of all the original tinned steel coaxial cable used throughout the connections and replace it with Cardas Litz cable. This is already done, just need reconnected to the new edge card connectors. I also had a new, better quality output pot made with the correct taper.
I hope everything works when I'm done. -
I'm sure it will. Do you have an alignment tape? Which one? I'm looking for one. Any suggestions?
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Hello,
I have a Sound Technology 1500 tape recorder analyzer which can test for lots of things including head alignment, record/playback frequency response, etc.
The best alignment tapes come from Magnetic Reference Laboratory at www.mrltapes.com
How about a few photos?
Regards, Ken -
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wowzers, that is gorgeous.
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Thanks for posting the photo, looks to be in really good shape. Tapesonic decks were produced by Premier Electronic Labs in New York city, a collaboration between machinist Adolph "Sam" Miller and electronics designer Harry Kolbe. Mr. Kolbe is still involved with good sound production, primarily electric guitar pickups and guitar amplifier/speaker combinations.
Do you have the 15ips add on capstan? For some reason my deck has some sort of extra post to the right of the head block. Not sure why it's there, tape won't stay on it as a guide.
It's nice to see it in the nice looking rack, mine came in a big road case that has needed some glueing.
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I have the big road-case for it. I also have the black head-block covers but I just leave them off. I'm currently looking for a 15 I.p.s. capstain sleeve. That extra post on yours may very well be a holder for it.Post edited by analog_stud on
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Here it is, currently in its road case with head-block covers present. -
Did some re-cap on the record and playback boards today. I stuck to the original composition and spec for the electrolytics. 5uf's are sprague (cost a fortune) and the rest are BC phillips. I love the sound of these preamps and didn't want to "clean it up" lol!
Tested and sounds sweet and punchy! -
Looks really good. Yea, I know what you mean it's always a question of making changes, but not to the point that it no longer sounds the way you want it to. Tough balancing act.
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Hey guys. I also own a Tapesonic 70T, i got it for $50 because a guy didn't know how to use it. I am a tech and want to make sure that everything is alright with the machine. Is there anyway I can get a copy of the schematics? I see that you have a picture with some schematics and if they are for the 70T, I would really love to get a copy. Please let me know!
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Well, I know it's been awhile since I've made any progress on the Tapesonic electronics, but now that I've got my work space set up and I've cleared up one or two other projects I can devote some time to it. I've finished cleaning and polishing the various potentiometers and attaching the Cardas cables for all the connections. The next challenge is to slowly fold up the face plate and install the controls as I go. Here's a photo:
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You missed a spot
Looking brand new
2-channel: Modwright KWI-200 Integrated, Dynaudio C1-II Signatures
Desktop rig: LSi7, Polk 110sub, Dayens Ampino amp, W4S DAC/pre, Sonos, JRiver
Gear on standby: Melody 101 tube pre, Unison Research Simply Italy Integrated
Gone to new homes: (Matt Polk's)Threshold Stasis SA12e monoblocks, Pass XA30.5 amp, Usher MD2 speakers, Dynaudio C4 platinum speakers, Modwright LS100 (voltz), Simaudio 780D DAC
erat interfectorem cesar et **** dictatorem dicere a -
That is some dedication Ken.
WOW!! -
The three shielded grey wires on the left bring the mains AC from the IEC socket to the front panel on/off switch and necessary relay connection points. All the blue cables are Cardas Litz shielded which go to the various level adjustments, selectors and input/output RCA sockets. Anyone who has worked with Litz wires knows how long it takes to remove all the insulation from each small strand, even the shielding braid strands are coated. I don't think I'll ever do that again. Through this whole process I was very anxious about everything fitting between the main chassis and the inside of the face plate. It's what kept me putting the final assembly together off for so long.
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Well, things are moving along. I tidied up the wiring and got the pots and selectors mounted. Not the easiest thing to do, holding the pot in position so the indicator lines up with the marks on the face plate and tightening up the 9/16" locking nut while preventing the pot from turning. Got the face plate installed on the chassis, tight fit. Measured the 24VDC power supply (got 24.77VDC) and installed the two playback boards and there was a signal at the output. So far so good. Now to measure the THD of the playback circuit and maybe connect a Teac transport and see what it sounds like.
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