TVs with audio push-pull? - UK Vintage Radio Repair and Restoration Discussion Forum

saddlestone-man · 18th Feb 2019, 8:24 pm

Hello All

I was wondering if any British TVs have been produced with push-pull audio outputs? i checked a couple of pre-war large cabinet TV/Radios eg the GEC BT8161 and the HMV model 900, but they seem to have used single-ended audio outputs.

best regards ... Stef

ParcGwyn · 18th Feb 2019, 8:31 pm

Ferguson 989T, pair of ECL80s in PP.

Dave

GW7ONS

saddlestone-man · 19th Feb 2019, 1:19 pm

Thanks Dave that's most useful.

Best rgds. Stef.

1100 man · 19th Feb 2019, 10:21 pm

Hi Stef,
I have a Dynatron TV32 405 TV from the later part of the '50's. It's a 21" console set and the chassis, complete with CRT is colossally heavy. I'm sure, from memory, it has push pull audio but I would have to check. I've not looked at it for some years.

All the best
Nick

Nuvistor · 19th Feb 2019, 10:26 pm

Good thread from David on the TV32.
https://vintage-radio.net/forum/showthread.php?t=108863

1100 man · 19th Feb 2019, 11:48 pm

Hi Frank,
Thanks for the link- I had not spotted that one before. I have just found the Dynatron leaflet that the seller gave me when I bought the TV. It shows the TV32M at 203gn! I must have bought it some time ago as it was at the old NVCF at the NEC. I seem to remember that I paid a tenner for it!

All the best
Nick

Biggles · 20th Feb 2019, 12:35 am

There was a bit of discussion on push pull ECL80 circuits on the forum a while back particularly regarding the problems associated with the fact that the pentode and triode sections share a common cathode.
Alan.

FERNSEH · 20th Feb 2019, 1:50 am

The Dynatron TV32 was discussed here: https://www.vintage-radio.net/forum/...d.php?t=108863

Another TV set with push-pull audio output was the Beau Decca. Uses a pair of PX4 triodes.
https://www.vintage-radio.net/forum/...d.php?t=137423

DFWB.

Sideband · 20th Feb 2019, 3:11 pm

Post number 18 in this thread, https://www.vintage-radio.net/forum/...ighlight=ecl80

shows the circuit based on the Ferguson P-P ECL80 circuit

dazzlevision · 20th Feb 2019, 4:15 pm

I’m pretty sure that some dual standard 1960s Dynatron mono TVs used 2xPCL82 in push-pull (Pye 40F or 67 chassis).
My Pye 23” CCIR standard export set (clearly of Ekco design) uses the same audio output arrangement. Made around 1965.

FERNSEH · 20th Feb 2019, 4:49 pm

Quote:

Originally Posted by dazzlevision

I’m pretty sure that some dual standard 1960s Dynatron mono TVs used 2xPCL82 in push-pull (Pye 40F or 67 chassis).
My Pye 23” CCIR standard export set (clearly of Ekco design) uses the same audio output arrangement. Made around 1965.

The Dynatron dual standard model TV95 employs a push-pull audio module which has two ECL80 triode-pentodes. The add-on amplifier is connected to the main chassis via the valveholder of the mono audio amplifier valve V16 (PCL82). The circuit is very similar to that in the 1954 Ferguson 103T series.

The Baird 638 schools TV receiver had an optional push-pull audio amplifier using two PCL82s.

DFWB.

Edward Huggins · 20th Feb 2019, 5:56 pm

Sound has always been the poor relation of TVs. Whilst the Console models sounded better, it was only because of the larger cabinet and, probably, an 8" loudspeaker.
Nearly of these consoles used the same AF/Output stages as the table models - and many of these were just a high-gain, single stage. Even today in the flat screen world the issue continues - hence the development of those very convincing Soundbars!

AC/HL · 20th Feb 2019, 8:51 pm

With wideband AM sound, even a table model would compete on fairly equal terms with the average radio back then. Possibly even some of the lesser radiograms.

FERNSEH · 21st Feb 2019, 12:19 pm

Circuit diagram of the push-pull audio amplifier fitted in the Dynatron TV95.

DFWB.

kalee20 · 21st Feb 2019, 1:38 pm

That looks very like - even down to component values - the Mullard 3W ECL80 push-pull amplifier circuit.

18th Feb 2019, 8:24 pm	#1
saddlestone-man Hexode Join Date: Mar 2009 Location: Cirencester, Gloucestershire, UK. Posts: 391	TVs with audio push-pull? Hello All I was wondering if any British TVs have been produced with push-pull audio outputs? i checked a couple of pre-war large cabinet TV/Radios eg the GEC BT8161 and the HMV model 900, but they seem to have used single-ended audio outputs. best regards ... Stef

18th Feb 2019, 8:31 pm	#2
ParcGwyn Hexode Join Date: Jun 2005 Location: Aberystwyth, Wales, UK. Posts: 358	Re: TVs with audio push-pull? Ferguson 989T, pair of ECL80s in PP. Dave GW7ONS

19th Feb 2019, 1:19 pm	#3
saddlestone-man Hexode Join Date: Mar 2009 Location: Cirencester, Gloucestershire, UK. Posts: 391	Re: TVs with audio push-pull? Thanks Dave that's most useful. Best rgds. Stef.

19th Feb 2019, 10:21 pm	#4
1100 man Octode Join Date: Apr 2016 Location: Ventnor, Isle of Wight, & Great Dunmow, Essex, UK. Posts: 1,377	Re: TVs with audio push-pull? Hi Stef, I have a Dynatron TV32 405 TV from the later part of the '50's. It's a 21" console set and the chassis, complete with CRT is colossally heavy. I'm sure, from memory, it has push pull audio but I would have to check. I've not looked at it for some years. All the best Nick

19th Feb 2019, 10:26 pm	#5
Nuvistor Dekatron Join Date: Aug 2013 Location: Wigan, Greater Manchester, UK. Posts: 9,433	Re: TVs with audio push-pull? Good thread from David on the TV32. https://vintage-radio.net/forum/showthread.php?t=108863 __________________ Frank

19th Feb 2019, 11:48 pm	#6
1100 man Octode Join Date: Apr 2016 Location: Ventnor, Isle of Wight, & Great Dunmow, Essex, UK. Posts: 1,377	Re: TVs with audio push-pull? Hi Frank, Thanks for the link- I had not spotted that one before. I have just found the Dynatron leaflet that the seller gave me when I bought the TV. It shows the TV32M at 203gn! I must have bought it some time ago as it was at the old NVCF at the NEC. I seem to remember that I paid a tenner for it! All the best Nick Attached Thumbnails

20th Feb 2019, 12:35 am	#7
Biggles Rest in Peace Join Date: Feb 2004 Location: Hexham, Northumberland, UK. Posts: 2,234	Re: TVs with audio push-pull? There was a bit of discussion on push pull ECL80 circuits on the forum a while back particularly regarding the problems associated with the fact that the pentode and triode sections share a common cathode. Alan.

20th Feb 2019, 1:50 am	#8
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: TVs with audio push-pull? The Dynatron TV32 was discussed here: https://www.vintage-radio.net/forum/...d.php?t=108863 Another TV set with push-pull audio output was the Beau Decca. Uses a pair of PX4 triodes. https://www.vintage-radio.net/forum/...d.php?t=137423 DFWB.

20th Feb 2019, 3:11 pm	#9
Sideband Dekatron Join Date: Oct 2003 Location: Croydon, Surrey, UK. Posts: 7,571	Re: TVs with audio push-pull? Post number 18 in this thread, https://www.vintage-radio.net/forum/...ighlight=ecl80 shows the circuit based on the Ferguson P-P ECL80 circuit __________________ There are lots of brilliant keyboard players and then there is Rick Wakeman.....

20th Feb 2019, 4:15 pm	#10
dazzlevision Dekatron Join Date: Sep 2003 Location: Near Swindon, North Wiltshire, UK. Posts: 3,611	Re: TVs with audio push-pull? I’m pretty sure that some dual standard 1960s Dynatron mono TVs used 2xPCL82 in push-pull (Pye 40F or 67 chassis). My Pye 23” CCIR standard export set (clearly of Ekco design) uses the same audio output arrangement. Made around 1965.

20th Feb 2019, 5:56 pm	#12
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,327	Re: TVs with audio push-pull? Sound has always been the poor relation of TVs. Whilst the Console models sounded better, it was only because of the larger cabinet and, probably, an 8" loudspeaker. Nearly of these consoles used the same AF/Output stages as the table models - and many of these were just a high-gain, single stage. Even today in the flat screen world the issue continues - hence the development of those very convincing Soundbars! __________________ Edward.

20th Feb 2019, 8:51 pm	#13
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,642	Re: TVs with audio push-pull? With wideband AM sound, even a table model would compete on fairly equal terms with the average radio back then. Possibly even some of the lesser radiograms.

21st Feb 2019, 12:19 pm	#14
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: TVs with audio push-pull? Circuit diagram of the push-pull audio amplifier fitted in the Dynatron TV95. DFWB. Attached Thumbnails

21st Feb 2019, 1:38 pm	#15
kalee20 Dekatron Join Date: Feb 2007 Location: Lynton, N. Devon, UK. Posts: 7,081	Re: TVs with audio push-pull? That looks very like - even down to component values - the Mullard 3W ECL80 push-pull amplifier circuit.