I got the belts from a German Ebay member for $12 and got it running!, sounds amazing and it has the same issue with one of the VU meters, which I have not dealt with yet. I really like it and am amazed some one would throw it away, such nice unit.
Similar situation here, stuk vu-meters as well ;-) Scavenged a very very nice looking Erres 6715 last week, haven't checked it out yet. But do i want to revive this beauty.. what a trashfind :-)
I have that same recorder, that last switch is actually Philips' version of noise reduction DNR (Dynamic Noise Reduction) it was quite an interesting noise reduction system, it was a "on-the-fly" playback processing system as it did not require pre-processing or encoding of the source material, there is a very interesting article online that explains exactly how it works. It's quite clever actually.
I was just about to say the same when I saw your reaction. Yep, that's what that knop with the green light is for. I have the bigger brother of this one, the Philips N4506. With the meters on the side and 4 din inputs on the back.
As Mr. Spock would say, Fascinating Captain. I have been intrigued with bias oscillation since I was a teen. Once bought a deck with no electronics and tried recording without distortion everyway I could think of. Had no clue about the bias oscillator, had no internet to search and never got that unit to record without distortion. Later I learned of the bias oscillator but never really understood it. Clearly you do and I have enjoyed this video emensley! Thanks, you know more about so many things then many. Obviously you're bias oscillator is functioning to perfection!
Before AC Bias recording the audio signal was presented directly to the head . This resulted in generally a voice quality recording at best with lots of distortion. DC bias first came along which applied a DC voltage to the recording head which reduced distortion by operating the tape substantially within its linear response region . The disadvantage of DC bias was that it left the tape with a slight magnetization, which caused significant noise on replay because of the grain of the tape particles. This also caused the playback head to become slightly magnetized which resulted in poor high frequency playback the more the head became magnetized DC-bias systems used a permanent magnet that was placed near the record head to erase the tape before recording. It had to be swung out of the way for play. DC bias was replaced by AC bias but was later re-adopted by some very low cost cassette recorders. AC Bias has a long history, and patent disputes over it's discovery, but basically a high frequency, anywhere from 40 to 100KHz AC signal is mixed in with the recorded signal. This AC signal is well beyond the maximum frequency that can be recorded and is used to erase, and fully saturate the tape during record. The thing about bias is it is a relatively critical adjustment that is taylored to specific tape formulations. Depending on the tape design, some materials require a higher bias. Chromium Dioxide for example, which was probably one of the best recording formulations required a higher bias. The problem with CrO2 as it was known, was even though it had superior high end, it was lacking in the bass department. BASF held the patent for Cro2 tape for many hears. Sony solved this problem with the lows on chrome tape. They invented a dual layer tape called Ferrichrome, or type 3 tape. Ferrichrome tape is just that, ferric oxide on the bottom layer, with chrome on top. It is very cool tape, brown looking from the back, black on top. This gave the best of both worlds, deep bass, and crisp highs. (I still have a box of unopened Sony type 3 tape, and dozens I used in my cassette days back in the 80's. Was wonderful and expensive tape initially. Almost as much as Metal tape. When Sony discontinued it I bought all I could find at a steep discount, and most people just overlooked it. Speaking of metal, it requires an even higher bias. If your bias is too low, your highs will be over emphasized and there will be much distortion. If the bias is too high, the highs will roll off and the sound will be dull. So bias requirements are relatively critical for the type of tape used. In the reel to reel arena, pretty much all the tape is quite similar. When I set this yo I used the service manual, set the bias to the level specified at the test point, then scoped the wiper of the pot I set reading the test point, and set the other channel to the same level so both channels have equal bias voltage.
11:16 The switch with the green light is for DNL (Dynamic Noise Limiter). Had the same machine. DNL reduces the noise by 10db, similar to Dolby B however without the special encoding required. National made a similar system called DNR (Dynamic Noise Reduction) because of patent issues.
Pioneer has their own version of DNR, but theirs is "Digital Noise Reduction" where they digitize the audio, remove the noise and then convert back to analog. It completely removes the noise. Works like bloody magic. I have such a deck and it is amazing.
@@12voltvids Ha, interesting stuff, didn't know that. Already searched information on Pioneer DNR, was on end of product line. I have some doubts about frequency cut-offs, saw some video's promoting the feature. dbx was also great however a dbx tape cannot be played full featured on equipment without dbx, sounds horrible ;-D I wished it was the standard at the beginning however it was developed too late, i think it had saved the format i guess.
@@codebeat4192 The digital noise reduction on my pioneer deck certainly sounds good on my deck. It has a plastic auto reverse transport too. If they had that on a 3 head on the playback side wow. How it works is actually quite simple. Unlike analog systems that just filter at different frequencies digital noise reduction digitized the incoming audio, @ 44.1khz 16 bit just like a cd. Data read into memory where an algorithm analyzes the waveform and removes the random noise then converts the now cleaned data stream back to analog. Toshiba did the same thing on VHS which significantly reduced chroma noise on bad tapes.
I really like that . Clear reels. Looks great "naked". I enjoy open reel, although I never had one, just portable mono units. I also noticed that if head alignment is not the same for recording and playback, it loses treble. Let me explain. Say you buy a deck (cassette, open reel, or even 8-track) and you buy a pre-recorded tape. And they did not record at the same head alignment as your deck. The treble won't be perfect. At least that's what my experience has been. And. I remember hearing the flyback transformer on a TV until about my mid twenties. So when you went above 7 khz, I couldn't hear it. I did hear differences when you was alternating the audio frequencies.
I've been watching your work for a while now. The amount of technicians who wouldn't even worry about that stuck meter is amazing to me! Before it was stolen, my Akai GXC 46D Cassette Deck had the bias set to the best chromium tapes you could get! New belts etc and recording with Dolby B noise reduction made no difference to the top end at all! Listening with headphones I could hear a slight loss of treble when I turned Dolby B on and off but it removed 90% of the hiss leaving the recording alone! I hope to find another GXC 46D but I yearn for the one that was stolen. It was out of the box new with a smokey grey lid to cover it when not in use! It never chewed any tape and I never played other peoples tapes to avoid fouling the heads and capstan/pinch roller with shitty cheap tapes. I really miss that deck!
@@12voltvids Just like in Fight Club when they use Degaussers to ruin all the VHS films! Ha ha. I like your style, having this knowledge makes us mischievous sometimes!
The knob with the green light is DNL, Dynamic Noise Limiter. As far as I could hear it, it moved with the music sort to speak. Sometimes you could hear the hiss of the tape come up with the high frequenties. But still it worked pretty good. I have the big brother of this one, the Philips N4506. Used to use it for my band back when we still recorded in my house. Because that thing is uge. You wouldn't try to take that with you.With 4 din inputs on the back for everything from a tuner to a record player. But I use a 8-track digital recorder now. Ok. somebody already said something about that knob. But I could not resist to talk about my old tape recorder which I still have but just don't use anymore. Plus it needs some maintenance....
Just to watch the reels turn right. Doesn't matter if the sound is coming from the tape, just to see the reels turning is cool to watch. Like tube amplifiers. Just the glow if the tubes over on the top of the stand in the corner. You can almost feel it warming up the room.
ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Gi01999sB8M.html this version was probably from reel tape ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-HOTXbXevB5s.html
Smashing job, between the owner and you it's spot on now. Always nice to work on decent quality equipment :-D Mechanical operation is just like new, the brakes are perfect, really nice condition. Looks like the rec/play head is ok too, ive seen too many with hf loss due to wear.
I'm still going to have study how you did the bios, three speeds and the sound quality checks. the adjusting points using the scope. I noticed in different videos, your oscilliscopes are different or you changed to a bigger scope. I do remember these. Sounds like it took a lot to get it back to almost factory specs. Sounded real good.
Very nice unit those. You're right, she's done a smashing job on that. I have one with the same 3 - motor mechanism, it has "Magno-Control" and is the more basic N4414, given to me by a good friend. After the usual fun with gooey belts, it works nicely.
I have a Panasonic Technics RS-741 US deck, could you tell me where the speed adjustment button is? I feel like he's a little faster compared to an Akai.
I have the same reel to reel, but for some reason it started playing slightly faster on all speeds but as it has individual speed pots for each speed I can't see how this is possible, is there a master speed setting?
You have been fooled, this isn't a N4504, these originally have only DIN (German) connectors and no 6.5mm headphone/mic jacks on the front. It is a Frankenstein machine. Some items have been assembled and added from donors. If You really want to use these you should try to get a N4512, basically the "No nonsense" version. It has no DNL and that had a reason, its noise level is so low it never needed it. The PLAY circuitry is completely offline to an amplifier (while recording). Only at playback the line-out is live. You can only listen (Monitor) the tape while recording with a headphone connected. BTW i get 12KHz freq. range out of 4.75cm/s if you bias calibrate it without an oscilloscope (hearing difference tape-source) and Maxell UD 18-180 tape.
Dave awesome video :) I have the same unit and ever time I push play I get smoke and heat from those big green resisters .....especially the big green one laying flat ... could one of my reel motors be bad . thanks Lloyd
I have a Sony TC 730 which I will be taking apart this weekend hoping to get down to the bottom of the problem I might play backboard when it's in forward playback it cuts out on both channels at the same time I've asked different people about it and they seem to think it's the switch on the play backboard I tried to detox in it but I didn't have very much deoxit left in the can so I ordered some more deoxidant and going to try again if you have any advice on what to do about this problem please let me know the people I've talked to on a group on Facebook that deal with reel-to-reels say that the switch needs to be replaced
Hello, can you be so kind to explain me what's the function of the middle button near the heads? As far as I understand, it makes the recording head inoperative, but I don't understand what's the purpose...prevent accidental recordings, not wearing the head unnecessarily? It's not a "SOS" function, right? Thank you.
This deck can make mono quarter track, or stereo quarter track recordings. That switch selects between mono or stereo mode. It has three positions, A) mono on track 1 or 4; B) mono on track 3 or 2; C) stereo on tracks 1and 3, or tracks 2 and 4. Read about it here: www.reeltoreel.de/worldwide/Tips09.htm.
Yep, they are a Dutch company, the service manual is in Dutch, no doubt not German. They don't make hifi equipment anymore, though, primarily medical stuf (MRI and such) and a separate lighting division. In the 80 and 90's I had a lot of their stuf, a friend of my father worked there and could buy Philips with considerable discount. Bought their first CD player CD100 /CD200 in 1983, still have it :-). Their later stuf was of lesser quality, though.
Dave, Its fun watching your videos. Maybe you can help me licate a test tape with 1000Hz signal. I recently purchased the Akai GX-270D reel to reel tape deck. Someone may have been trying to adjust 3 3/4 speed and left it a bit off. Can we get in touch? Regards Alex
@@12voltvids Ha! that is the first thing everyone says ...nope motor is stamped 60 hz. I spoke to Gary at VM he was going to get me the specs of what RPM it should be... but he never got round to it. you can live with it... but don't play a pre-recorded tape on it because you can really tell the speed difference..lol. the back of the unit says 105 - 110 AC volts... my lines are 120- 125 I think that is the problem.
@@bones007able Hmm, well motor speed is governed by the AC frequency. When the run capacitor gets weak they will slow down though as they loose torque and they just run out of steam.
hey bud , wonder if you can help me , i have a tc-280 and i want to calibrate the vu meters . I have a signal generator app i know i need to set the freq to 700mhz but what so i set the amp too (in %) to set the meters to 0 . many thanks for any help .
(Note) : In this scenario, both "rec level" potmeters on the front of the machine should be set to "max", that's what the attenuator is used for inbetween signal generator and "line in" RCA's on the back of the RTR, to get to that point.
My Philips tape deck has a sticky meter too, I tought that it was a bad capacitor or something. Good thing that I'm not the only one who cleans connectors because they look disgusting.
What's your point. I am not sticking my hand anywhere near energized parts. When I do I remove it first. Notice I do not wear a wedding ring. I have a real nice one that my wife bought when we were married, but I am an electrician,and for safety I don't wear it. If I am sticking my hand in something energized I remove my watch, but then again you will never see me put both hands on an energized device. One hand is in my pocket when I work on high voltage devices. On this tape deck the highest voltage is only 20 or so volts The main filter is rated at 35 volts. It is a low voltage unit, unlike my Akai which uses AC motors.
All those patched in wires on main board shows really bad pcb design by Philips. This is a very decent performing deck considering all the cheap plastic parts in it.
Such a pain, and you didn't even touch physical alignment on the heads. I've got a Braun TG1000/4, a German service manual, and it's just sitting there, accusing me of procrastination.
Here is the thing. The heads don't get out of alignment on their own. They are paint sealed at the factory. The head will wear with excessive use but that will not change the alignment. The only time alignment needs to be done is if the head has been replaced or if somebody's been in there and messed with it. Sure if the unit was dropped and the chassis was bent the heads would be out of alignment but you'd have a lot more to worry about than just the heads being out of alignment if the chassis was bent. Same with your car your wheels typically will not go out of alignment unless a the wheel bearings wear out are the tie rod ends wear out or b) you hit something like a pot hole or curb. I don't see many take heads hitting a curb or pothole 😁
