Grundig TK 23 Reel-to-Reel Tape Recorder Video #2 - 60Hz Setting
ฝัง
- เผยแพร่เมื่อ 2 พ.ย. 2014
- This German tape recorder is playing recordings made in Germany too fast. There is a simple wiring change to operate the recorder on 60Hz but this setting was left on 50Hz and may be causing the recorder to run at the wrong speed. I make the wiring change to 60Hz and check the speed to see if it changed.
- วิทยาศาสตร์และเทคโนโลยี
Jim you are in the correct path. The only thing that is missing is to change the electric motor pulley ( most of the time is Brass made).Most of the German 220-240V, 50Hz tape recorder come with a pulley with larger diameter than those imported and adapted into the USA. You need to change or made a new electric motor's pulley with smaller diameter.The Grundig tape recorders made within the 60-70's came with AC (alternate current) motors. AC motor depends on voltage's frequency. The larger the frequency the faster it spins. This is why you need to reduce the motor pulley to reduce the speed propagated into the CAPSTAN.
Ach du lieber! Das klingt großartig!
Good job!
My Grundig TK 247 has a voltage setting where you can set from 110V to 240V and also set from 50hz to 60hz. According to the factory, it's set at 110V and 60hz. That's on the back of the unit itself.
The motor is a synchronous induction motor and runs at a speed determined by the mains frequency. You can't change that. But you can change the 'gear' ratio of the belt drive between the motor and the capstan. The motor pulley will need to be slightly smaller, to get the tape right speed (3.25 in/sec) on 60Hz. If you can't find one, it's theoretically possible to machine the one you have. But another solution, which I think you might like better, is to build an inverter running at 50Hz to power the whole thing. Just need a 12-0-12 mains transformer of suitable rating, a drive source which can be logic IC's wired to give antiphase 50Hz square waves, and some big transistors or MOSFETS... you might even be able to score one off ebay at the right price; if it's 60Hz it can be modified to 50Hz a lot easier than the Grundig! Re the popping; since the head output is in the microvolt region the playback amp gain is enormous and it is not unusual for them to reproduce random spikes picked up from the mains. I had a Philips EL4303 (BC109 era solid state reel to reel) back in the 70's that picked up the local taxi firm very faintly!
Great Alan!
Now I realize the foolishness of my thinking around the frequency - just because I moved the jumper doesn't change the power line frequency so the motor is always syncing to 60Hz no matter what. I think I can award myself another Duh. More dumb thinking around the jumper was that it was provided to change the speed. I now think it was provided so the motor will run 'better', probably more efficiently, with the correct setting to match the power line frequency. Mister Claws hinted at this in his comment.
Your external solution is intriguing. I've had the pulley solution in the back of my mind but I think it might be impossible to find a conversion pulley. Your external solution could be applied to any other machine too. I'm going to check into frequency converters. Alan, thanks for these really helpful ideas. Jim.
Jim Lindenas You're more than welcome Jim, I do a lot of the same kind of things and I always thoroughly enjoy your videos. I tried to find out the power consumption of the TK23, which as far as I can tell is only 60 watts- if so (and you will know becuase it will be written on it somewhere!), you could use this inverter: www.ebay.co.uk/itm/Power-Inverter-150W-DC-12V-AC-220V-50Hz-FF-0468-/330536834089 which is cheap and would not be working too hard at that! I also stumbled across this thread too which you might find interesting as it discusses the frequency issue as well as transformers... vintage-radio.net/forum/showthread.php?t=65903 :)
Check the capstan for a removable sleeve.
Hi wonder if you could help.. I have a Grundig TK17L the main belt has broken. How difficult would it be to replace it? Do i need to take off all the mechanism on top of the main fly wheel or is there a simple lift up part to slide it through? any help would be appreciated!!
No speed adjustment on the motor itself ?
MercMad Didn't see anything like that on the motor.
Hello ! Do you know how to connect output the machine to a soundcart ? It a din wire, I think but where from, please ? Thanks !
On the back of the grunding there are 4 imputs. One of them is for the output cable, I think the first one from the left
Hi Jim, why does this not surprise me...usually this is not gonna work that easy, as you need to change some rotating parts as well. For some machines grundig provides some different pulleys and/or wheels, but they are very hard to get, as they all intened to be used in machines, witch where brought to other countries by the people itself.
When machines left the factory for overseas shipping they had the needed pulleys already mounted inside. As grundig had worldwide shipping that days.
Thanx for sharing, anyway.
TubiCal Is the motor synchronous in this machine. Does the line frequency control the motor speed at all?
I think, your wiring video shows a normal two pole synchronous motor. But if you got the UM/SM already there should be a note upon this in it. As i mentioned it before, i do not own a 23L therefore i´m just guessing upon my experiences with all the other grundig machines that i´ve had restored over the years (46/47/25/28/16/820) they do all have a synchronous motor inside.
I done a workaround for this on my Hammond ´53 M3 US-model (there was no export model) i´ve used a step down tranny for the amplifier. But to run the toneweel motor with the right speed (60Hz synchronous type) i´ve built up a 120V/60Hz source. With a 60Hz sinewave generator (tunable a nice feature to have, as well) a power amplifier (Simple Class B and solid state - of course) and a 24V/230V mains tranny reversed to have 120V output from the former primary winding.
Works well since years now, but i think this would be to complicated for just a little R2R.
I think that you just made the power supply happy by changing those taps. I had an old Akai reel-to-reel and there was a mechanical switch to change to different idler wheels on the motor for 50 vs. 60 Hz. I suspect that if you put in a tape made on a different machine it would be fast since the motor was designed for 50 Hz. Unless there is a mechanical idler wheel adjustment OR a 60 Hz tap on the motor, there will be nothing you can do to fix the speed.
MisterClaws From the schematic, the connection change I made is essentially a change to the windings on the motor.
you can always set it to 130V instead of 110. Probably wont make much difference
I was thinking there might be a pulley conversion for it.