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

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > General Vintage Technology > Components and Circuits

Notices

Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets.

Closed Thread
 
Thread Tools
Old 16th Jan 2013, 1:59 pm   #21
kalee20
Dekatron
 
Join Date: Feb 2007
Location: Lynton, N. Devon, UK.
Posts: 5,166
Default Re: UY85 UL84 Amplifier

It is negative current feedback, taken from the cathode resistor and fed back to the input. So no it won't correct any non-linearities in the O/P transformer. Also, the damping on the loudspeaker will be nearly non-existent.

There are tone controls, but they are within the feedback loop which consequently will try to nullify them!

An interesting circuit, but not what I'd call a 'good' circuit.
kalee20 is offline  
Old 19th Feb 2013, 10:55 pm   #22
Fidelity Fan
Hexode
 
Join Date: Jan 2013
Location: Wigan, Lancashire, UK.
Posts: 318
Default Re: UY85 UL84 Amplifier

Back to UY85 - UL84 amplifiers - If for safety, an isolation transformer was fitted to one of these record players from which the BSR motor was also supplied, what current/VA rating would the isolation transformer need to be?
Fidelity Fan is offline  
Old 20th Feb 2013, 12:23 am   #23
Herald1360
Dekatron
 
Herald1360's Avatar
 
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 13,708
Default Re: UY85 UL84 Amplifier

The motors don't take much power though they may need rather more VA.

Heaters are about 9W, HT maybe 12W or so, allow 25VA for the motor and a 50VA transformer should do the biz. Go for 100VA if you want it all to stay nice and cool.
__________________
....__________
....|____||__|__\_____
.=.| _---\__|__|_---_|.
.........O..Chris....O
Herald1360 is offline  
Old 20th Feb 2013, 5:45 pm   #24
Fidelity Fan
Hexode
 
Join Date: Jan 2013
Location: Wigan, Lancashire, UK.
Posts: 318
Default Re: UY85 UL84 Amplifier

Ok thanks.
Fidelity Fan is offline  
Old 30th Sep 2013, 7:15 pm   #25
AC/HL
Moderator
 
AC/HL's Avatar
 
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 7,643
Default Re: UY85 UL84 Amplifier

One post about the Radio Constructor articles moved to the Websites section for information.
__________________
Bill, BVWS member
AC/HL is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 5:50 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 - 2019, vBulletin Solutions, Inc.
Copyright ©2002 - 2019, Paul Stenning.