sobell tape machine inputs. Help!

[Gone 6 days now]

I have a an old tape machine from the 60's which I feel like using for some (insert buzz word) "lofi" effect. the problem is that the machine only has phono input and outputs, so how would i connect a mic to this?

[jpmorris]

Depends on the mic. If it's XLR and needs 48v phantom power, get a cheap mic preamp. You might find one with phono connectors, if not, buy or build a 1/4" jack->phono lead.
If the mic has a 1/8" or 1/4" plug, you'll just need an appropriate female jack -> male phono lead.

If the mic is one of these 'plug-in-power' ones that requires a 1.5v source, you'll probably be better off buying another mic as it won't work for this.

[Gone 6 days now]

Thanks for the advice, I made a phono to jack lead and hooked up the mic but there is another problem, the tape records but no signal is heard during play back. Is it because the microphone needs a power source, it is a cheap £1 mic.

[jpmorris]

You might be able to bodge it by placing a 1.5v battery in series with the input - I think I've seen it done like that before. But you'd probably be better off just getting a cheap dynamic mic, or anything else that doesn't need plug-in power.

[Dr ZEE]

Originally Posted by Gone 6 days now

I have a an old tape machine from the 60's ...

What brand /model?

Originally Posted by Gone 6 days now

the tape records but no signal is heard during play back....

How do you know that "the tape records"?

Originally Posted by Gone 6 days now

it is a cheap £1 mic.....

what exactly mic is it, brand/model?

/later

[Dr ZEE]

uh, I've found your older post. some 60s Sobell machine. Had to do some "investigative work" to figure out what the question is about.
Now, where is my "paycheck" ?
********

still have no clue what exactly machine we are talking about. the mystery still there.

...woking on it

/later

[Gone 6 days now]

still have no clue what exactly machine we are talking about. the mystery still there.

it is a sobell festival from the 60's and i know it can record because there is two lights each with writing above them. They say play and record. I did get the machine to record but it makes a low beep sort of noise when i talk into the microphone, which is unbranded.

[Dr ZEE]

are those "lights" with writings above them moving (green or blue) or just lamps?
********
Does this recorder have two input jack - one "LINE" (or "High") and the other "MIC" (ot "LOW")

If so, can (or could) you record some line-lavel audio (like from CD-player / tuner / tape recorder / mixer output etc) and play it back fine? (assuming using "Line" input jack)

I also assume that your recorder has Vacuum Tubes in it? Correct?

[Gone 6 days now]

The inputs on the machine are: mic, rad, p.u and speaker. The lights are two lamps, they do not glow blue or green, and it does not say play it says pilot, sorry for any mistake. there are two mullard tubes in the machine but I cannot remember the serial number of them.

[Dr ZEE]

uh, cool
so, first of, the fact that those lamps come "ON" does not really mean much in term of your recorder's "health".
Pilot - "shows" you that the unit is "ON"
"Record" lamp shows you that the machine is in "record" mode (mechanically speaking ), but it does not really mean (it does not indicate) that the recording actually occurs.

ok,
so, I guess "rad" - means "radio" (?), so I guess this is "High" level input.
So did you try to record something from a CDplayer or a tuner or mixer output, using that "rad" input jack?
If not, then try and see if you get sometheing recorded and then play it back.
If you can accomplish that, then the machine is ok, and the problem is in your microphone (or microphone connection).

I am just trying to sort of figure out if your recorder actually works.
Also, I don't know a thing about your recorder, so it's just my guessing.

[Gone 6 days now]

I have not recorded a cd on to it yet but i am planning to do so, also the record light only flashes when i speak at a certain volume. Thanks for all the info Dr Zee and I will get a pic of the machine up tonight

[Gone 6 days now]

Success!! I played a cd through the rad input and can hear the music through the sobell speaker. Now a new problem as poked its ugly head. the record switch only works in the middle between on and off which means i cannot get the play switch in full play position. I suppose i will just have to crack it open and see what i can do. Also some pics

[Dr ZEE]

Be very careful when opening up the machine.
Turn it off and UNPLUG the power cord.
Also, even after you turn it off and unplug , the Power Supply's electrolytic capacitor(s) can still hold DANGEROUS charge for long time.
Do NOT touch ANY contacts with hand. NEVER touch contacts with both hands - USE ONE HAND if you have to touch some contact(s), (keep the other in the pocket ), wear some rubber bottom shoes. Actually if you have rubber gloves - put them on.
This is not a joke.
Read this thread (maybe more than you need to read or know, but it does not hurt):
http://www.diyaudio.com/forums/showt...threadid=30172
*******

Now, if the REC lamp is "flashing to the music" then I am not sure what kind of lamp is it nor what technical idea/circuit serves it -

all I'm aware of is one of these: http://www.akh.se/tubes/eyes.htm

post some photos, that would be great.

[Gone 6 days now]

Thanks for the safety checks, i didn't know it could be that serious. I tried uploading pictures ut they were too big, i will have to try and cut the size down.

[cjacek]

Yeah, I too was surprised by the warning posted by the good Doc. Not that I would go into a machine that deep but it's good to know about the dangers!

-----

[Dr ZEE]

The Danger is there,
AND!
My name isn't Albert,

[jpmorris]

Originally Posted by Dr ZEE

Now, if the REC lamp is "flashing to the music" then I am not sure what kind of lamp is it nor what technical idea/circuit serves it

In the absence of photos, I'd guess it's either a magic eye, or simply an overload indicator. To a degree how dangerous the recorder's internals are depends on the technology used. A 1960s recorder could either be valve or transistor. If it's transistorized, it should be reasonably safe (with the exception of the power supply, and possibly the motors). If it's a valve unit it could be running to hundreds of volts and the warnings above apply in full force.

Could you upload the pictures to photobucket or something?

[Dr ZEE]

Originally Posted by jpmorris

I'd guess it's either a magic eye, or simply an overload indicator.

maybe something like dm160: http://www.r-type.org/exhib/aai0056.htm
i've never seen those in person.

[Gone 6 days now]

Sorry i have not replied in a while but my internet was broken, the wonders of technology. Does anyone know a site I can upload pictures, the smallest resolution on my camera is still too big. the machine was built in 1961 and is indeed a valve circuit.

[jpmorris]

Originally Posted by Gone 6 days now

Sorry i have not replied in a while but my internet was broken, the wonders of technology. Does anyone know a site I can upload pictures, the smallest resolution on my camera is still too big. the machine was built in 1961 and is indeed a valve circuit.

Try http://www.photobucket.com
You'll have to register, though, but if it thinks the files are too big it will automatically resize them for you.

[Gone 6 days now]

here is a link to the first one
http://i248.photobucket.com/albums/g...w/DSCF2995.jpg

more coming