Philips N4450 Reel to Reel Tape Player - Page 3 - UK Vintage Radio Repair and Restoration Discussion Forum

Michael Maurice · 22nd Jul 2019, 12:39 pm

Quote:

Originally Posted by Ray_Singh

I managed to screw up the power on/off switch on both machines. Does anyone have spare please?

You'll be lucky! When the switch on a machine I was repairing failed, I used a TV switch but had to modify it and the bracket to accommodate it.

Ray_Singh · 22nd Jul 2019, 4:49 pm

Thanks Maurice.

Will these work? The pictures show switches with different number of pins.

https://www.ebay.com/itm/3x-Universa...-/131842932300

Michael Maurice · 22nd Jul 2019, 9:15 pm

I doubt you'll get that to fit. None of the switches on Ebay will fit.

Ray_Singh · 24th Jul 2019, 9:30 pm

I now have two switches. One with the usual problem - will not engage into the on position easily and one switch with a lose, broken connector.

Can anyone help me with guidance on how to make one good switch out of the two?

Ray_Singh · 19th Sep 2019, 7:50 pm

Finally - She breathes!!!!

My Dad fixed the on/off switch after loosing a spring from inside the switch itself! All sorted now - thanks Dad.

My 10.5" plastic AGFA spools arrived with some classic Elvis on them and i went to collect a pair of vintage Wharfedale speakers from Odiham today. Once back, i put all the bits together and hit play...

She lives and plays perfectly. I am in love!!

Thank you for all your help and advice. I have a spare machine if anyone wants parts or perhaps a little challenge of their own....

Ray_Singh · 19th Sep 2019, 8:17 pm

Argh... I spoke too soon. Whilst playing Elvis this evening i decided to check what the Scratch and Rumble buttons do. I pressed these as the tape was playing and it seems to have triggered the machine into an odd mode. The reels just go into fast forward wind, spilling tape everywhere.

Any ideas where to look first?

ben · 19th Sep 2019, 9:25 pm

Scratch and rumble are filters that reduce the treble and bass respectively, dating from the days of vinyl records. I have no idea what they have to do with a tape machine!

I suspect it is coincidence and some component in the logic cct has died.

Sideband · 19th Sep 2019, 10:44 pm

The scratch and rumble filters have NO EFFECT ON TAPE TRANSPORT at all. All they do is apply a small amount of treble-cut (Scratch filter) or a small amount of bass-cut (Rumble Filter) to the audio signal only....and I think it is done in the pre-amplifier stages of the main amplifier so they don't effect the line output quality.

More than likely is the some component has failed (worth checking the AC128 transistors in the flip-flops) as these can become intermittent.

ben · 20th Sep 2019, 12:05 am

In all my years I have never seen such controls fitted to a tape recorder. We live and learn!

I suspect that pressing the button(s) moved the pcb slightly, and some marginal solder joint cracked.

Sideband · 20th Sep 2019, 6:10 am

The N4450 can also be used as a 'straight-through' Hi Fi amplifier so it's conceivable that noisy records etc could be played directly hence the rumble and scratch filters.

Back in the day it was intended to be the 'central item'. It even has an output for Philips Motional Feedback speakers.

Reelman · 20th Sep 2019, 12:00 pm

Quote:

Originally Posted by Sideband

Back in the day it was intended to be the 'central item'. It even has an output for Philips Motional Feedback speakers.

I believe that this machine predates the MF loudspeakers. Whilst it has a fairly high fixed level output available at the “monitor” socket the tone and volume controls have no effect on it thus the MF speakers would probably work but at constant full volume.

Later machines like the N4506 did provide a dedicated output for the MF speakers and provided tone and volume control over it.

I’d love to try a pair of these speakers with my N4506 or N4422 machines if I ever came across them... at a reasonable price!

The N4450 was certainly designed to be the “centre of your Hi-Fi system” so provided the amplifier controls expected at the time such as scratch/rumble filters and “phys” compensation. This was Philips take on the loudness or contour control.

Peter

TonyDuell · 20th Sep 2019, 5:07 pm

The N4450 does not have the MFB speaker output, alas. I suspect it would not be too hard to add one though.

But the MFB speakers I have (and must get round to testing and trying out) can take the input from the speaker outputs of another amplifier. OK, having that amplifier in the chain will increase distortion (you're basically amplifying the signal to speaker levels, then attenuating it, then amplifying it again with the MFB signal applied) but it shouldn't be too bad. I bought said speakers to use with the N4450.

Welsh Anorak · 20th Sep 2019, 5:09 pm

Michael did warn you! The AC128 transistors are notorious and it's a good idea to change them all for modern beefier types (cf post #22). It'll only cost a few pounds and your machine will thank you for it. At least your motors (another but more serious weakness) are OK.

Ray_Singh · 20th Sep 2019, 11:29 pm

I tried the machine again after its 'funny moment' yesterday and it works fine again. What is going on?

I will take the advice and replace the AC128s.
@welsh anorak - what does cf post 22 mean? Its late and i cant work it out?

Many thanks

TonyDuell · 21st Sep 2019, 12:06 am

'cf'' is 'conferatur' which strictly means 'compare' but is commonly used to mean 'see'

'post 22' means message 22 in this thread

My N4450 had various problems (the worst was going into record mode which would erase the tape) until I replaced those AC128s. I used BC640s but other transistors work too.

ben · 21st Sep 2019, 2:45 am

Quote:

Originally Posted by Ray_Singh

I tried the machine again after its 'funny moment' yesterday and it works fine again. What is going on?

...see post 49. Have you tried prodding those buttons again to see if the problem reappears? That would suggest a dry joint if so.

But those transistors wreak havoc, so I would heed the advice and replace.

Ray_Singh · 4th Oct 2019, 1:45 pm

Thanks all. So far the issue has not re-occurred, so i am not going to replace transistors just now.

Another problem has manifested itself however....

When recording, if the tape is in record mode, the switch marked A/B can be flicked to hear what the quality and level of the input signal is versus the recorded signal quality and level.

I am noticing that the left channel experiences a serious degradation in level. The signal is still present but i estimate around 10-15% less than it should be.

Any ideas please? I have cleaned the heads with Metholated spirits to no avail.

julie_m · 4th Oct 2019, 3:18 pm

This could be a sign of head wear if you are very unlucky

or just poor tape-to-head contact if you are more fortunate

This always seems to affect the left-hand channel first, because it's at the outside of the tape.

Sideband · 5th Oct 2019, 7:55 am

Very worn heads are easy to spot. Sometimes a groove is worn in the area above and below the headgaps. If this is the case there is only one answer but where you find suitable heads after all this time is debatable. Back in the day, Philips used to supply a complete assembly with all the heads mounted or they could be replaced individually.

Ray_Singh · 6th Oct 2019, 9:10 pm

Thanks Julie_m and Sideband.

I will take pictures of the heads to show you to see if you can spot wear. I have a spare machine i can take the heads from and would like to change the whole assembly rather than a single head as i understand that you have to align the head and this can be hard.

22nd Jul 2019, 4:49 pm	#42
Ray_Singh Pentode Join Date: Jun 2019 Location: Marlborough, Wiltshire, UK. Posts: 179	Re: Philips N4450 Reel to Reel Tape Player Thanks Maurice. Will these work? The pictures show switches with different number of pins. https://www.ebay.com/itm/3x-Universa...-/131842932300

22nd Jul 2019, 9:15 pm	#43
Michael Maurice Moderator Join Date: Feb 2006 Location: Wembley, Middlesex Posts: 7,222	Re: Philips N4450 Reel to Reel Tape Player I doubt you'll get that to fit. None of the switches on Ebay will fit. __________________ Forum Moderator http://www.michaelmauricerepairs.co.uk/

24th Jul 2019, 9:30 pm	#44
Ray_Singh Pentode Join Date: Jun 2019 Location: Marlborough, Wiltshire, UK. Posts: 179	Re: Philips N4450 Reel to Reel Tape Player I now have two switches. One with the usual problem - will not engage into the on position easily and one switch with a lose, broken connector. Can anyone help me with guidance on how to make one good switch out of the two?

19th Sep 2019, 7:50 pm	#45
Ray_Singh Pentode Join Date: Jun 2019 Location: Marlborough, Wiltshire, UK. Posts: 179	Re: Philips N4450 Reel to Reel Tape Player Finally - She breathes!!!! My Dad fixed the on/off switch after loosing a spring from inside the switch itself! All sorted now - thanks Dad. My 10.5" plastic AGFA spools arrived with some classic Elvis on them and i went to collect a pair of vintage Wharfedale speakers from Odiham today. Once back, i put all the bits together and hit play... She lives and plays perfectly. I am in love!! Thank you for all your help and advice. I have a spare machine if anyone wants parts or perhaps a little challenge of their own....

19th Sep 2019, 8:17 pm	#46
Ray_Singh Pentode Join Date: Jun 2019 Location: Marlborough, Wiltshire, UK. Posts: 179	Re: Philips N4450 Reel to Reel Tape Player Argh... I spoke too soon. Whilst playing Elvis this evening i decided to check what the Scratch and Rumble buttons do. I pressed these as the tape was playing and it seems to have triggered the machine into an odd mode. The reels just go into fast forward wind, spilling tape everywhere. Any ideas where to look first?

19th Sep 2019, 9:25 pm	#47
ben Dekatron Join Date: Aug 2006 Location: Madrid, Spain / Wirral, UK Posts: 7,498	Re: Philips N4450 Reel to Reel Tape Player Scratch and rumble are filters that reduce the treble and bass respectively, dating from the days of vinyl records. I have no idea what they have to do with a tape machine! I suspect it is coincidence and some component in the logic cct has died. __________________ Regards, Ben.

19th Sep 2019, 10:44 pm	#48
Sideband Dekatron Join Date: Oct 2003 Location: Croydon, Surrey, UK. Posts: 7,566	Re: Philips N4450 Reel to Reel Tape Player The scratch and rumble filters have NO EFFECT ON TAPE TRANSPORT at all. All they do is apply a small amount of treble-cut (Scratch filter) or a small amount of bass-cut (Rumble Filter) to the audio signal only....and I think it is done in the pre-amplifier stages of the main amplifier so they don't effect the line output quality. More than likely is the some component has failed (worth checking the AC128 transistors in the flip-flops) as these can become intermittent. __________________ There are lots of brilliant keyboard players and then there is Rick Wakeman.....

20th Sep 2019, 12:05 am	#49
ben Dekatron Join Date: Aug 2006 Location: Madrid, Spain / Wirral, UK Posts: 7,498	Re: Philips N4450 Reel to Reel Tape Player In all my years I have never seen such controls fitted to a tape recorder. We live and learn! I suspect that pressing the button(s) moved the pcb slightly, and some marginal solder joint cracked. __________________ Regards, Ben.

20th Sep 2019, 6:10 am	#50
Sideband Dekatron Join Date: Oct 2003 Location: Croydon, Surrey, UK. Posts: 7,566	Re: Philips N4450 Reel to Reel Tape Player The N4450 can also be used as a 'straight-through' Hi Fi amplifier so it's conceivable that noisy records etc could be played directly hence the rumble and scratch filters. Back in the day it was intended to be the 'central item'. It even has an output for Philips Motional Feedback speakers. __________________ There are lots of brilliant keyboard players and then there is Rick Wakeman.....

20th Sep 2019, 5:07 pm	#52
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,208	Re: Philips N4450 Reel to Reel Tape Player The N4450 does not have the MFB speaker output, alas. I suspect it would not be too hard to add one though. But the MFB speakers I have (and must get round to testing and trying out) can take the input from the speaker outputs of another amplifier. OK, having that amplifier in the chain will increase distortion (you're basically amplifying the signal to speaker levels, then attenuating it, then amplifying it again with the MFB signal applied) but it shouldn't be too bad. I bought said speakers to use with the N4450.

20th Sep 2019, 5:09 pm	#53
Welsh Anorak Dekatron Join Date: Apr 2005 Location: North Wales, UK. Posts: 6,916	Re: Philips N4450 Reel to Reel Tape Player Michael did warn you! The AC128 transistors are notorious and it's a good idea to change them all for modern beefier types (cf post #22). It'll only cost a few pounds and your machine will thank you for it. At least your motors (another but more serious weakness) are OK. __________________ Glyn www.gdelectronics.wales

20th Sep 2019, 11:29 pm	#54
Ray_Singh Pentode Join Date: Jun 2019 Location: Marlborough, Wiltshire, UK. Posts: 179	Re: Philips N4450 Reel to Reel Tape Player I tried the machine again after its 'funny moment' yesterday and it works fine again. What is going on? I will take the advice and replace the AC128s. @welsh anorak - what does cf post 22 mean? Its late and i cant work it out? Many thanks

21st Sep 2019, 12:06 am	#55
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,208	Re: Philips N4450 Reel to Reel Tape Player 'cf'' is 'conferatur' which strictly means 'compare' but is commonly used to mean 'see' 'post 22' means message 22 in this thread My N4450 had various problems (the worst was going into record mode which would erase the tape) until I replaced those AC128s. I used BC640s but other transistors work too.

4th Oct 2019, 1:45 pm	#57
Ray_Singh Pentode Join Date: Jun 2019 Location: Marlborough, Wiltshire, UK. Posts: 179	Re: Philips N4450 Reel to Reel Tape Player Thanks all. So far the issue has not re-occurred, so i am not going to replace transistors just now. Another problem has manifested itself however.... When recording, if the tape is in record mode, the switch marked A/B can be flicked to hear what the quality and level of the input signal is versus the recorded signal quality and level. I am noticing that the left channel experiences a serious degradation in level. The signal is still present but i estimate around 10-15% less than it should be. Any ideas please? I have cleaned the heads with Metholated spirits to no avail.

4th Oct 2019, 3:18 pm	#58
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: Philips N4450 Reel to Reel Tape Player This could be a sign of head wear if you are very unlucky or just poor tape-to-head contact if you are more fortunate This always seems to affect the left-hand channel first, because it's at the outside of the tape. __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.

5th Oct 2019, 7:55 am	#59
Sideband Dekatron Join Date: Oct 2003 Location: Croydon, Surrey, UK. Posts: 7,566	Re: Philips N4450 Reel to Reel Tape Player Very worn heads are easy to spot. Sometimes a groove is worn in the area above and below the headgaps. If this is the case there is only one answer but where you find suitable heads after all this time is debatable. Back in the day, Philips used to supply a complete assembly with all the heads mounted or they could be replaced individually. __________________ There are lots of brilliant keyboard players and then there is Rick Wakeman.....

6th Oct 2019, 9:10 pm	#60
Ray_Singh Pentode Join Date: Jun 2019 Location: Marlborough, Wiltshire, UK. Posts: 179	Re: Philips N4450 Reel to Reel Tape Player Thanks Julie_m and Sideband. I will take pictures of the heads to show you to see if you can spot wear. I have a spare machine i can take the heads from and would like to change the whole assembly rather than a single head as i understand that you have to align the head and this can be hard.