UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Radio (domestic)

Notices

Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only.

Closed Thread
 
Thread Tools
Old 11th Sep 2020, 8:04 am   #1
PJC58-Hythe
Heptode
 
PJC58-Hythe's Avatar
 
Join Date: Sep 2010
Location: Hythe, Hampshire, UK.
Posts: 626
Default Help - Grundig 8055/W/3D

I'm currently repairing a Grundig 8055/W/3D with an outboard circuit which is a clearly a pre-amp with some equalisation. The input states "Collaro Transcription Cartridge" and the output is connected to the normal PU input. My question is what is the Collaro cartridge mentioned (it's missing from the arm) I've never run across one of these.

Hoping someone can help
Attached Thumbnails
Click image for larger version

Name:	Pre-Amp.JPG
Views:	129
Size:	58.8 KB
ID:	215407  
__________________
Peter - M0HYT - BVWS Member - GQRP Club

http://www.retroworkshop.co.uk
PJC58-Hythe is offline  
Old 11th Sep 2020, 12:10 pm   #2
Edward Huggins
Dekatron
 
Join Date: Sep 2015
Location: Southwold, Suffolk, UK.
Posts: 8,302
Default Re: Help - Grundig 8055/W/3D

This is liable to be for the Collaro Studio "P" crystal cartridge (c.50mV) or the (even better) Collaro/Ronette TX88 cartridge. Both are rare, have wide frequency ranges and a relatively low output - hence the pre-amp add-on circuit.
__________________
Edward.
Edward Huggins is offline  
Old 11th Sep 2020, 3:20 pm   #3
PJC58-Hythe
Heptode
 
PJC58-Hythe's Avatar
 
Join Date: Sep 2010
Location: Hythe, Hampshire, UK.
Posts: 626
Default Re: Help - Grundig 8055/W/3D

Thanks for the information Edward, that now makes sense. Looks like I'm going to have to install a ceramic pickup and skip the pre-amp if they are so rare.
__________________
Peter - M0HYT - BVWS Member - GQRP Club

http://www.retroworkshop.co.uk
PJC58-Hythe is offline  
Old 24th Sep 2020, 3:19 pm   #4
PJC58-Hythe
Heptode
 
PJC58-Hythe's Avatar
 
Join Date: Sep 2010
Location: Hythe, Hampshire, UK.
Posts: 626
Default Re: Help - Grundig 8055/W/3D

To keep the circuit original I used a Sontra CS25 stereo ceramic cartridge which has the following specification:

Output: 45 mV 1cm/s at 1000 Hz
Frequency Response: 20Hz to 18 kHz
Compliance: 6 x 10(-6) cm/dyne
Tracking Force: 3 to 5 grams

It sounds fantastic!
__________________
Peter - M0HYT - BVWS Member - GQRP Club

http://www.retroworkshop.co.uk
PJC58-Hythe is offline  
Old 25th Sep 2020, 9:46 am   #5
Edward Huggins
Dekatron
 
Join Date: Sep 2015
Location: Southwold, Suffolk, UK.
Posts: 8,302
Default Re: Help - Grundig 8055/W/3D

Quote:
Originally Posted by PJC58-Hythe View Post
Thanks for the information Edward, that now makes sense. Looks like I'm going to have to install a ceramic pickup and skip the pre-amp if they are so rare.
No, you will still need to use that dedicated pre-amp section. Most "new" ceramic stereo cartridges have a far lower output than you might expect!
__________________
Edward.
Edward Huggins is offline  
Old 25th Sep 2020, 1:05 pm   #6
PJC58-Hythe
Heptode
 
PJC58-Hythe's Avatar
 
Join Date: Sep 2010
Location: Hythe, Hampshire, UK.
Posts: 626
Default Re: Help - Grundig 8055/W/3D

It's not a 'modern' cartridge it's an original Sontra coupled to the pre-amp.

The output is exactly right when switching between Radio / PU - and as I said it sounds fantastic!
__________________
Peter - M0HYT - BVWS Member - GQRP Club

http://www.retroworkshop.co.uk
PJC58-Hythe is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 3:54 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.