Grundig party center 700 problem - UK Vintage Radio Repair and Restoration Discussion Forum

ljones0 · 19th Dec 2015, 10:56 pm

Hello all!

Just trying to work out a possible problem here. This device is an old (I think dating from the mid 1980s) tape recorder/radio device. You can see a picture of the device here btw.

Almost everything with the device seems to be OK. Radio works (though the frequency band change; LW/SW/MW/FM switch is a little sticky). The EQ works too; tape rewind and forward wind don't seem to be slow. Playing a tape there dosen't appear to be much evidence of wow and flutter.

The only problem seems to be with recording. I've tried chrome/metal type tapes (the device does have a tape type switch). Though the switch dosen't seem to do a whole lot, nothing really not even a crackle or pop through changing it.

Distortion seems to take place when recording on a higher quality tape with the device set in "II/Cr IV/Me pb" mode - there's noticible distortion. In the other mode "I/Fe" there dosen't seem to be any problems.

I tried recording a short piece of audio. This is the original piece of audio; this is the recording on higher quality tape with the device set to II/Cr IV/Me pb; this is on ordinary tape set to "I/Fe".

The recording made at II/Cr IV/Me pb seems to be - well I can only describe it as "grainy" or "crunchy" and with a small degree of elevated noise as well. The other recording dosen't seem to have this problem.

I'm wondering maybe could the bias oscillator be at fault here? Maybe one side or part of it is dead or doing nothing and causing the distortion.

Thanks

ljones

paulsherwin · 19th Dec 2015, 11:09 pm

It looks as if the tape type switch just changes the playback equalisation to match chrome recordings made elsewhere, and that this recorder can't actually record on chrome tape.

ljones0 · 20th Dec 2015, 2:05 am

Intresting! Well all is not lost then I guess -- at least it means it's not faulty and I can just use ordinary tapes. Should be able to get fairly reasonable results if I use normal tapes, then import them to a computer and adjust the frequencies in VLC.

ljones

paulsherwin · 20th Dec 2015, 2:17 am

It depends what you're trying to use it for. Radio cassettes like these aren't a good choice if you want to digitize old cassettes. Very good hifi cassette decks can be avaiable for next to nothing and are a much better choice if you can do the maintenance.

In this case, apart from the 'pb' (playback) the giveaway is a single switch position for chrome and metal tapes. These formulations use the same playback equalisation but completely different bias levels.

The better ferric tapes can give good results with basic recorders. The HF lift provided by underbiased tapes like TDK AD can combat the HF rolloff found with most cheap'n'cheerful machines. Maxell UD/XLI tapes can sound just as good as UD/XLII apart from the worse noise levels resulting from the different equalisation.

Nickthedentist · 20th Dec 2015, 6:38 pm

As Paul implies, in spite of the brand, this is a cheap, mid-1980s radio/cassette with detachable speakers, probably sourced from Malaysia, Taiwan, Singapore etc and aimed at kids'/teenagers' bedrooms.

So, clean the tape path and enjoy it for what it is, but don't expect too much.

paulsherwin · 20th Dec 2015, 6:44 pm

There were a number of these "sheep in wolf's clothing" designs around in the 80s, pretending to be much better systems than they were, though that doesn't mean that they're complete junk of course. I owned a very similar Philips unit in the 80s.

Brian R Pateman · 20th Dec 2015, 6:57 pm

A typical example is this Pye model TR-3845. It's Philips behind the badge and made in Austria.

A very good performer.

Nickthedentist · 20th Dec 2015, 7:54 pm

The tape transport looks identical. I would be surprised if it's not the same inside, give or take.

LJ, is your Grundig made in Austria too?

N.

paulsherwin · 20th Dec 2015, 8:48 pm

Philips carried on making radio cassettes in Austria until well into the 90s, though lots of subassemblies were bought in, probably including the mech shown here. ISTR my Philips was made in Austria, though it would have been a year or two earlier than the models being discussed here

Despite the big SERVO on the front of the Grundig, these mechs had soft touch mechanical controls rather than servo operation as that is normally understood.

19th Dec 2015, 10:56 pm	#1
ljones0 Tetrode Join Date: Feb 2007 Location: Fordingbridge, Hampshire, UK. Posts: 56	Grundig party center 700 problem Hello all! Just trying to work out a possible problem here. This device is an old (I think dating from the mid 1980s) tape recorder/radio device. You can see a picture of the device here btw. Almost everything with the device seems to be OK. Radio works (though the frequency band change; LW/SW/MW/FM switch is a little sticky). The EQ works too; tape rewind and forward wind don't seem to be slow. Playing a tape there dosen't appear to be much evidence of wow and flutter. The only problem seems to be with recording. I've tried chrome/metal type tapes (the device does have a tape type switch). Though the switch dosen't seem to do a whole lot, nothing really not even a crackle or pop through changing it. Distortion seems to take place when recording on a higher quality tape with the device set in "II/Cr IV/Me pb" mode - there's noticible distortion. In the other mode "I/Fe" there dosen't seem to be any problems. I tried recording a short piece of audio. This is the original piece of audio; this is the recording on higher quality tape with the device set to II/Cr IV/Me pb; this is on ordinary tape set to "I/Fe". The recording made at II/Cr IV/Me pb seems to be - well I can only describe it as "grainy" or "crunchy" and with a small degree of elevated noise as well. The other recording dosen't seem to have this problem. I'm wondering maybe could the bias oscillator be at fault here? Maybe one side or part of it is dead or doing nothing and causing the distortion. Thanks ljones

19th Dec 2015, 11:09 pm	#2
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,966	Re: Grundig party center 700 problem It looks as if the tape type switch just changes the playback equalisation to match chrome recordings made elsewhere, and that this recorder can't actually record on chrome tape.

20th Dec 2015, 2:05 am	#3
ljones0 Tetrode Join Date: Feb 2007 Location: Fordingbridge, Hampshire, UK. Posts: 56	Re: Grundig party center 700 problem Intresting! Well all is not lost then I guess -- at least it means it's not faulty and I can just use ordinary tapes. Should be able to get fairly reasonable results if I use normal tapes, then import them to a computer and adjust the frequencies in VLC. ljones

20th Dec 2015, 2:17 am	#4
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,966	Re: Grundig party center 700 problem It depends what you're trying to use it for. Radio cassettes like these aren't a good choice if you want to digitize old cassettes. Very good hifi cassette decks can be avaiable for next to nothing and are a much better choice if you can do the maintenance. In this case, apart from the 'pb' (playback) the giveaway is a single switch position for chrome and metal tapes. These formulations use the same playback equalisation but completely different bias levels. The better ferric tapes can give good results with basic recorders. The HF lift provided by underbiased tapes like TDK AD can combat the HF rolloff found with most cheap'n'cheerful machines. Maxell UD/XLI tapes can sound just as good as UD/XLII apart from the worse noise levels resulting from the different equalisation.

20th Dec 2015, 6:38 pm	#5
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,861	Re: Grundig party center 700 problem As Paul implies, in spite of the brand, this is a cheap, mid-1980s radio/cassette with detachable speakers, probably sourced from Malaysia, Taiwan, Singapore etc and aimed at kids'/teenagers' bedrooms. So, clean the tape path and enjoy it for what it is, but don't expect too much.

20th Dec 2015, 6:44 pm	#6
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,966	Re: Grundig party center 700 problem There were a number of these "sheep in wolf's clothing" designs around in the 80s, pretending to be much better systems than they were, though that doesn't mean that they're complete junk of course. I owned a very similar Philips unit in the 80s.

20th Dec 2015, 6:57 pm	#7
Brian R Pateman Nonode Join Date: Jun 2005 Location: Western Lake District, Cumbria (CA20) - UK Posts: 2,136	Re: Grundig party center 700 problem A typical example is this Pye model TR-3845. It's Philips behind the badge and made in Austria. A very good performer. Attached Thumbnails __________________ Brian

20th Dec 2015, 7:54 pm	#8
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,861	Re: Grundig party center 700 problem The tape transport looks identical. I would be surprised if it's not the same inside, give or take. LJ, is your Grundig made in Austria too? N.

20th Dec 2015, 8:48 pm	#9
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,966	Re: Grundig party center 700 problem Philips carried on making radio cassettes in Austria until well into the 90s, though lots of subassemblies were bought in, probably including the mech shown here. ISTR my Philips was made in Austria, though it would have been a year or two earlier than the models being discussed here Despite the big SERVO on the front of the Grundig, these mechs had soft touch mechanical controls rather than servo operation as that is normally understood.