Reel ality Check

[thebes]

Swung by an estate sale after doing an estimate on Saturday morning for the heck of it and ended lugging out a 47lb monster of a reel to reel recorder. It's a tube equipped (NEC's and one telefunken) Roberts (AKAI) 770X. At $65 I apparently got no bargain.

LarryC was by later that day to pick up some albums and was kind enough to bring along an old tape he recorded. He used his amazing analytical abilities to solve a problem I was having with my Preamp and, as a bonus, he also gave me the rundown on how to string the tape. I replaced a popped fuse, fired it up, and it ran for an hour with no problems. I've since cleaned the head with head cleaner and am now ready for the next step which is actually hooking this beast up to my stereo.

So here's some questions.

I'm guessing I use 1/4 adapters to regular RCA plugs and hook them into the Left and Right Pre-Amp Outs shown in the picture. There is also a DIN connection not shown in the pic located on the side of the player. So what do I do?

Also in another picture is how I've hooked up the tape. Larry was basically ignoring a little wheel on the left but since it had some cotton in it I presumed this was to clean the tape and hooked the tape through that. Is this correct?

Also there is another spindle located almost in the center to the right above the head box (the thing with the big X on it). This has a roller on it and I think it might be for the 15 second tapes. Is this correct and if so how do I hook up a high spped tape to it (if I ever get one)?

Also, do I use the volume knobs on the recorder to set a volume level or leave that entirely to my regular pre-amp?

Finally what is the "Sound On Sound" button for and what about that Red button to the right of the head? If I press it will I launch ICBM's against Russia?

Not sure if I want to go the RTR route and if this baby is not up to snuff I understand the amps can be pulled and with some easy modifications turned into integrated SET monos. If I go this route I'll be sure to start a SET thread.[]

[thebes]

[thebes]

Here's another pic:

[bluesboy]

Wow that's an interesting looking rig. One thing I saw right off the bat is it looks like the tape should run over the top of the first small spindle and then under the pinch roller. Pictures of the back of the deck would be usefull.

[Tarheel]

Connect the output terminals on the tape deck to the "tape in" or "tape monitor" on your amp/preamp. Conect the "line out" "record out" or "tape out" terminals on your amplifier to the "line in" terminals on the tape deck. These are general guidelines as I am not familiar with your Roberts.

The little lever directly over the red button is a tension arm and takes up slack in the tape and stabilizes the tape. Gently move the tape reel forward till the tape pulls the arm to the top of the arc.

You have three tape speeds and the highest (7.5) will make the best quality tape.

If you get the deck running tape and the tape slips off the rubber on the pinch roller you can remove the roller and rough it up with 220 qrit sand paper. When the rubber gets old or worn it usually gets slick causing the tape to wander.

Use the volume control knobs on your deck to adjust the volume coming in to the deck. The needle on the vu meter should barely go into the red area on the loudest passages.

A tubed reel to reel at that price could be a real bargain if it operates properly.

Good luck.

[oldenough]

Hi Thebes, i think you will find that machine is actually an Akai product, or at least the same as. I'll do a little research and get back to you.

[oldenough]

Oops, re-read your initial post....you already knew it was an Akai(M8).

[leok]

Thebes,

Nice tape deck. I had an Akai X200-D .. somewhat similar.

I think you have the tape threaded correctly for record/playback. I don't think the tape should go over the top of the roller on the left side as suggested above.

The extra spindal just above and to the right of the heads is for winding/re-winding without going through the heads. The tension arm on the right has to be included in any wind-rewind operation or the motor(s) won't go. It also provides auto cutoff for the wind operations.

Enjoy!

Leo

[WMcD]

A buddy used to have one. The following is what I recall.

You do have it threaded properly. That first roller might be to clean the oxide side of the tape so that bad stuff does not clog the playback head..

There is an added capstan, or capstan cover which you have on the holder. When you put it on the thin capstan, the speeds change up to 3.25 and 7.5 ips. There is a screw mechanism to secure it.

You do adjust the level on the tape deck. The tape out on your preamp is constant and is not affected by the level control on the preamp. In fact, you can probably turn down the gain on the pre-amp to zero and still get a full level feed to the tape player.

X Field: As you may know, tape recorders rely on a bias signal. Please recall that on later cassette types there were different bias settings for "metal tape." Not a concern here, but you may remember the term.

The bias is a very high freq mixed on top of the audio signal to the record head. One explanation is that this excites the oxide particles and they come to rest in the magnetic orientation established by the audio signal.

Apparently there is a problem. Maybe the gap in the record head saturates with the added bias signal. The solution is to have another head supply the bias signal. But how do you get it in the same place as the record head gap?

The answer is to have the bias head on the non-oxide side of the tape. If you take off that X cover, you should see the bias head facing up from the bottom. Hence "cross field."

Sound on sound: Probably this a dubbing feature. You first record on one (left?) track with Larry singing. Then you play it back with sound on sound. The output of the left is fed to the right track, but you can also add a second source to have Thebes singing in addition, and recording the mix on the right track. I'm not sure of this, exactly.

You can experiment or find a manual.

You may recall that Sgt Pepper and albums in those years used a similar technique to build up build up layers of sound. It was when four tracks on a studio machine was state of the art. They were building up a lot more than could be done with a single pass.

In my recall, these Roberts were very good decks. 7.5 ips was indistinguishable from the source. 3.5 ips was pretty close. Background hiss was the limiting factor. Dolby noise reduction eventually was used on other decks.

It looks to me that you don't have a three-head deck. In that set up there was a separate record and playback head; with each optimized for their role. But I may be wrong.

Gil

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[johnyholiday]

[Y]nice 2 tracker

[Marvel]

Very nice! Some models had built in speakers (stereo playback), so they included 6BQ5 SE amps.

Gil is right about Sgt. Peppers. They used two four-track machines. Record four tracks, and mix them over to two on the second deck. They may have even added a couple of other instruments during the mix. Add a couple more tracks and mix those back to the first deck. I did the same one time, and got up to about fourteen tracks. Ahem, the Beatles I am not, but it worked incredibly well.

Bruce

[thebes]

Wow is this a great Forum or what!

I really appreciate all the help especially the detailed explanation you offered Gil. Yes when I pulled the cover to clean the heads there is one on the bottom end. They were pretty dirty, by the way ,which means if the thing sounds any good I'm going to have to open her up and oil up the various parts and certainly recap the amps.

Regarding that little spindle on the left on the far left side of it is an opening stuffed with cotton so I figured it had some sort of cleaning function that wouldn't be useful unless the tape ran over it. Glad to see that confirmed.

Also the confirmation on the connection to my system pre. Now that I've got my the system this will be used on pretty much to my liking, I didn't want to fryolate it with some massive amount of untamed electricity. Now fryolate is a Thebesian term I employ and is similiar to the sound of frozen french fries hitting the friar at your local MccDonalds.

Since my first forays into the world of all this stereo/electronic stuff I've heard that sound more than I care to think of. I guess sometimes the "what could possibly go wrong" principal I live by needs to be amended. Of course that won't stop me from pressing that red button just to see what it can do.

Now if this all works out tand he "test to destruction" tape Larry gave me doesn't get eaten, demagnetized or sliced into a thousand ribbons, does anybody have any spare tapes they can lend me?

Oh on the Set thing with these amps, this could be a cheap way into a SET experience. while the Forum was transitioning yesterday I noodled around the web and came upon this AK thread with a detailed explanation of how to convert them. Since they sell on ebay for less than a hundred ($350 new in 1965) it could be a no brainer.

http://www.audiokarma.org/forums/showthread.php?t=79384&highlight=roberts+770

[thebes]

Very nice! Some models had built in speakers (stereo playback), so they included 6BQ5 SE amps.

Gil is right about Sgt. Peppers. They used two four-track machines. Record four tracks, and mix them over to two on the second deck. They may have even added a couple of other instruments during the mix. Add a couple more tracks and mix those back to the first deck. I did the same one time, and got up to about fourteen tracks. Ahem, the Beatles I am not, but it worked incredibly well.

Bruce

Yup they did come with speakers (don't have them) and they do have two 6BQ5's, a couple of El 86's (one Telefunken and one NEC) and a couple of of 12 Ad7's which I understand are easily replaced with 12 AX7's. The other thing I noticed is the built in fan is one of the quietest small fans I've ever heard and it even has little flaps on the side you open to let the tube heat out. Pretty nifty gizmo.

[Marvel]

I know you really know this, but the red button is the record button. Using it and moving the control to play will erase the tape... or put on whatever you feed into it.

[Tarheel]

I have a few recorded and blank 7" reels you can have. No need to return....I use mostly 10" reels. PM me your address if you want them.

[LarryC]

[Y]nice 2 tracker

Do you think it's a 2-track? Why? It has those 2-3 and 1-4 designations to the right of that circular knob, whatever it is.

[thebes]

Eureka!

It works. Hooked it up as suggested. Pots are a little scratchy and volume can be adjusted from the deck and my pre. Larry recorded different stuff in mono on this tape on each separate track so if I turn up the right volume I get some piano concertos and if I turn up the left one I get a guy singing. There is some tape hiss but only if you are very close to the speaker. No "wow and flutter" so far. Amazing considering this thing probably hasn't been used in a couple of decades.

Watching those reels turn round and round, though, is making me a little queasy. I may have to lie down.

Glad to hear pushing that red button will not launch any missiles.

Very, very kind of you Tarheel. PM sent.

Oh by the way Gil, Larry singing on one channel and myself on the other would probably bring the demise of civilization as we know it.

[Marvel]

[Y]nice 2 tracker

Do you think it's a 2-track? Why? It has those 2-3 and 1-4 designations to the right of that circular knob, whatever it is.

A quarter track stereo. Only two channel playback or record. Without seeing the manual, I bet you use it with the Sound on Sound feature. Probably record the first two tracks on 1-3 as normal. Rewind the tape and switch to the 2-4. You mix the 1-3 pair onto 2-4 wile adding new material. Just a guess.

Bruce

[LarryC]

I wondered if "2 tracker" meant he thought it was half-track. Marty describes quarter-track playback, just as you said.

Because it was tres cheap, I ordered an operator's manual on CD from Ebay which I'll share with Marty.

[ZAKO]

No No dont touch the red button !!!! it will make your belly button fall off !!!!