Dansette Viva. - UK Vintage Radio Repair and Restoration Discussion Forum

FERNSEH · 7th Jun 2019, 5:41 pm

I'm repairing a Dansette Viva record player. The amplifier consists of the usual very simple two valve circuit of UL84 output and UY85 rectifier. The initial fault of no sound was that the UY85 had died, but what caused it to fail? Turned out to be that the UL84 retaining clip had short circuited to the HT tag on the output transformer.
It's an easy fix so far but the sound output is low because a medium output stereo pick-up cartridge has been fitted, an X5H would be better.
So how about a simple transistor single stage preamplifier? I'm sure this has been discussed before. An alternative but not so easy solution is change the UL84 for an UCL82 triode-pentode. Again, I'm sure that idea has been discussed elsewhere in the forum.

DFWB.

Nuvistor · 7th Jun 2019, 5:59 pm

UCL82, matching the ceramic cartridge would be easier than a transistor unless you tried a FET.

John10b · 7th Jun 2019, 6:06 pm

Yes you are right this topic has been discussed before, I’m not sure how to link you up, but if you do a search it should come up.
I would always stick to a valve solution and not mix with transistors.
Cheers
John

Nuvistor · 7th Jun 2019, 6:25 pm

https://www.vintage-radio.net/forum/...d.php?t=111572

https://www.vintage-radio.net/forum/...d.php?t=124429

BRASSBITS · 7th Jun 2019, 7:06 pm

Quote:

Originally Posted by FERNSEH

I'm repairing a Dansette Viva record player. The amplifier consists of the usual very simple two valve circuit of UL84 output and UY85 rectifier. The initial fault of no sound was that the UY85 had died, but what caused it to fail? Turned out to be that the UL84 retaining clip had short circuited to the HT tag on the output transformer.
It's an easy fix so far but the sound output is low because a medium output stereo pick-up cartridge has been fitted, an X5H would be better.
So how about a simple transistor single stage preamplifier? I'm sure this has been discussed before. An alternative but not so easy solution is change the UL84 for an UCL82 triode-pentode. Again, I'm sure that idea has been discussed elsewhere in the forum.

DFWB.

Why go the long way round? Just fit a cartridge with suitable output.

AC/HL · 7th Jun 2019, 8:17 pm

£40 versus time and the spares box?
Depends whether it's yours or a Customer's.

Edward Huggins · 8th Jun 2019, 8:58 am

The VIVA was Dansette's most basic and budget autochange record player ever....
You can buy a HTC8 re-manufacturerd cartridge for £35-00, but this is a Mono-only type. Sourcing a suitable high-output stereo compatible cartridge for single-stage amps is virtually impossible these days. You could rewire for an UCL82, but do bear in mind that this player only has a 5" diameter small magnet speaker and may not give full justice to such a conversion.

Herald1360 · 8th Jun 2019, 10:08 am

Plenty of possibilities in the links.

Just to be different (and reflecting my junk box) I've just done a Bermuda with a non inverting LF411 fed via a 47k resistor and four series 6V8 zeners from the HT rail.

Easy to mount the Veroboard and tagstrips to the wooden base of the cabinet and (not that it's likely anyone will ever bother) easy to reverse in future.

Ed_Dinning · 8th Jun 2019, 7:47 pm

Hi David, I have used the TAA320 chip from Mullard with success in this application. I might even have shown the circuit in a thread about 3 years back.
But plenty of other circuits on the forum to do this if you can take the Si solution

Ed

AC/HL · 8th Jun 2019, 9:25 pm

It's in this thread: https://www.vintage-radio.net/forum/...d.php?t=124429 which eventually produces a working design, although the OP opts to use a Velleman k1018 module.

FERNSEH · 15th Jun 2019, 9:14 pm

Quote BRASSBITS:
"Why go the long way round? Just fit a cartridge with suitable output."

Well I did find a BSR X5H in the shop but unfortunately it was faulty.

So now the Dansette Viva has a simple pre-amplifier which employs a BC549 low noise transistor.
The extra stage of amplification has certainly boosted the sound output, that's good but not so good the hum level has been amplified. In the workshop the mains is supplied from an isolation transformer operating in an earth free zone. Having no earthed mains sockets means record players of this type produce a lot of hum, not so bad when connected to the normal earthed sockets away from the workbench. Nevertheless the hum level is still too high.
The two pickup BS415 isolation capacitors are only 0.003microfarads each which mean the reactance is 1Mohms @ 50Hz. When the isolation capacitor on the earthy side is shorted out the hum is reduced to an acceptable level.
However, the capacitors are an essential fitment.
In the Stella ST561 record player the pickup isolation capacitors are mounted on the record deck close to the pickup wires tag strip.

For the next repair to this type of record player I'll use the TAA320 IC as suggested by Ed.

DFWB.

buggies · 16th Jun 2019, 6:35 pm

That blue wire (from the mains switch?) seems to be wrapped round the input capacitor...

FERNSEH · 16th Jun 2019, 7:57 pm

Hi George,
the blue wire is the mains supply to the anode resistor of the UY85. It will be repositioned well away from the audio leads.
We've always got concerns about safety with this type of equipment but at least the record deck is connected to the mains earth. To be honest it might be a better idea to remove the valve amplifier and fit a Velleman solid state amplifier which will be supplied from an isolated power supply.
Then there will be no more worries about safety. Benefits will be reduced hum and reduced heat dissipation .

DFWB.

tracypaper · 16th Jun 2019, 10:33 pm

If you don't fancy stripping the BSR X5H to get it going again, can I have it please?
Gaz.

FERNSEH · 16th Jun 2019, 11:27 pm

Hi Gaz,
I've sent you a PM.

DFWB.

FERNSEH · 21st Jun 2019, 10:27 am

A new audio amplifier chassis will be constructed for this record player. The Velleman amplifier module and the mains transformer will be mounted on a metal plate which will replace the old printed circuit board. The pickup mains isolation capacitors can now be removed.
The mains transformer was removed from a video recorder. The amplifier will be supplied with 14volts. The Velleman amplifier can operate from supplies of 8 to 18volts.
The faulty UY85 was not made by Mullard. Note the symbol to the right of the BVA logo, this indicates it was sourced from a third party. Most likely to be Mazda.

DFWB.

John10b · 21st Jun 2019, 12:13 pm

Well you made your decision and it looks tidy. Hope you get the results you want.
I would always stick to valves, but that's me showing my age

Cheers
John

FERNSEH · 21st Jun 2019, 3:59 pm

Hi John,
Nothing wrong with valves and in fact if the Viva was equipped with a mains transformer there would be no reason to replace the old amplifier.
The new amplifier was tested today and I can report it gives excellent results.
The IC used in the Velleman module is the TDA2003.

DFWB.

Heatercathodeshort · 23rd Jun 2019, 6:14 pm

I'm surprised you crossed the floor with this one David installing 'crystal valves' to replace the original valve amplifier.

To put a top hat on it you also employed one built on one of those printed circuit novelties.

To be honest David I don't blame you. These record players were safe in their day when nobody took them apart and fiddled with them, fitting sockets to play modern equipment etc. Some recent posts have scared me a bit.

At least it will be safe and more suited to modern standards. John.

7th Jun 2019, 5:41 pm	#1
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Dansette Viva. I'm repairing a Dansette Viva record player. The amplifier consists of the usual very simple two valve circuit of UL84 output and UY85 rectifier. The initial fault of no sound was that the UY85 had died, but what caused it to fail? Turned out to be that the UL84 retaining clip had short circuited to the HT tag on the output transformer. It's an easy fix so far but the sound output is low because a medium output stereo pick-up cartridge has been fitted, an X5H would be better. So how about a simple transistor single stage preamplifier? I'm sure this has been discussed before. An alternative but not so easy solution is change the UL84 for an UCL82 triode-pentode. Again, I'm sure that idea has been discussed elsewhere in the forum. DFWB. Last edited by FERNSEH; 7th Jun 2019 at 6:11 pm.

7th Jun 2019, 5:59 pm	#2
Nuvistor Dekatron Join Date: Aug 2013 Location: Wigan, Greater Manchester, UK. Posts: 9,432	Re: Dansette Viva. UCL82, matching the ceramic cartridge would be easier than a transistor unless you tried a FET. __________________ Frank

7th Jun 2019, 6:06 pm	#3
John10b Nonode Join Date: Nov 2016 Location: Aberaeron, Ceredigion, Wales, UK. Posts: 2,884	Re: Dansette Viva. Yes you are right this topic has been discussed before, I’m not sure how to link you up, but if you do a search it should come up. I would always stick to a valve solution and not mix with transistors. Cheers John

7th Jun 2019, 6:25 pm	#4
Nuvistor Dekatron Join Date: Aug 2013 Location: Wigan, Greater Manchester, UK. Posts: 9,432	Re: Dansette Viva. https://www.vintage-radio.net/forum/...d.php?t=111572 https://www.vintage-radio.net/forum/...d.php?t=124429 __________________ Frank

7th Jun 2019, 8:17 pm	#6
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,642	Re: Dansette Viva. £40 versus time and the spares box? Depends whether it's yours or a Customer's.

8th Jun 2019, 8:58 am	#7
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,327	Re: Dansette Viva. The VIVA was Dansette's most basic and budget autochange record player ever.... You can buy a HTC8 re-manufacturerd cartridge for £35-00, but this is a Mono-only type. Sourcing a suitable high-output stereo compatible cartridge for single-stage amps is virtually impossible these days. You could rewire for an UCL82, but do bear in mind that this player only has a 5" diameter small magnet speaker and may not give full justice to such a conversion. __________________ Edward.

8th Jun 2019, 10:08 am	#8
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: Dansette Viva. Plenty of possibilities in the links. Just to be different (and reflecting my junk box) I've just done a Bermuda with a non inverting LF411 fed via a 47k resistor and four series 6V8 zeners from the HT rail. Easy to mount the Veroboard and tagstrips to the wooden base of the cabinet and (not that it's likely anyone will ever bother) easy to reverse in future. Attached Thumbnails __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

8th Jun 2019, 7:47 pm	#9
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,194	Re: Dansette Viva. Hi David, I have used the TAA320 chip from Mullard with success in this application. I might even have shown the circuit in a thread about 3 years back. But plenty of other circuits on the forum to do this if you can take the Si solution Ed

8th Jun 2019, 9:25 pm	#10
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,642	Re: Dansette Viva. It's in this thread: https://www.vintage-radio.net/forum/...d.php?t=124429 which eventually produces a working design, although the OP opts to use a Velleman k1018 module.

15th Jun 2019, 9:14 pm	#11
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Dansette Viva. Quote BRASSBITS: "Why go the long way round? Just fit a cartridge with suitable output." Well I did find a BSR X5H in the shop but unfortunately it was faulty. So now the Dansette Viva has a simple pre-amplifier which employs a BC549 low noise transistor. The extra stage of amplification has certainly boosted the sound output, that's good but not so good the hum level has been amplified. In the workshop the mains is supplied from an isolation transformer operating in an earth free zone. Having no earthed mains sockets means record players of this type produce a lot of hum, not so bad when connected to the normal earthed sockets away from the workbench. Nevertheless the hum level is still too high. The two pickup BS415 isolation capacitors are only 0.003microfarads each which mean the reactance is 1Mohms @ 50Hz. When the isolation capacitor on the earthy side is shorted out the hum is reduced to an acceptable level. However, the capacitors are an essential fitment. In the Stella ST561 record player the pickup isolation capacitors are mounted on the record deck close to the pickup wires tag strip. For the next repair to this type of record player I'll use the TAA320 IC as suggested by Ed. DFWB. Attached Thumbnails

16th Jun 2019, 6:35 pm	#12
buggies Heptode Join Date: Jan 2009 Location: West Lothian, UK. Posts: 761	Re: Dansette Viva. That blue wire (from the mains switch?) seems to be wrapped round the input capacitor... __________________ George

16th Jun 2019, 7:57 pm	#13
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Dansette Viva. Hi George, the blue wire is the mains supply to the anode resistor of the UY85. It will be repositioned well away from the audio leads. We've always got concerns about safety with this type of equipment but at least the record deck is connected to the mains earth. To be honest it might be a better idea to remove the valve amplifier and fit a Velleman solid state amplifier which will be supplied from an isolated power supply. Then there will be no more worries about safety. Benefits will be reduced hum and reduced heat dissipation . DFWB.

16th Jun 2019, 10:33 pm	#14
tracypaper Octode Join Date: Aug 2010 Location: Beeston, Leeds, West Yorkshire, UK. Posts: 1,234	Re: Dansette Viva. If you don't fancy stripping the BSR X5H to get it going again, can I have it please? Gaz.

16th Jun 2019, 11:27 pm	#15
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Dansette Viva. Hi Gaz, I've sent you a PM. DFWB.

21st Jun 2019, 10:27 am	#16
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Dansette Viva. A new audio amplifier chassis will be constructed for this record player. The Velleman amplifier module and the mains transformer will be mounted on a metal plate which will replace the old printed circuit board. The pickup mains isolation capacitors can now be removed. The mains transformer was removed from a video recorder. The amplifier will be supplied with 14volts. The Velleman amplifier can operate from supplies of 8 to 18volts. The faulty UY85 was not made by Mullard. Note the symbol to the right of the BVA logo, this indicates it was sourced from a third party. Most likely to be Mazda. DFWB. Attached Thumbnails

21st Jun 2019, 12:13 pm	#17
John10b Nonode Join Date: Nov 2016 Location: Aberaeron, Ceredigion, Wales, UK. Posts: 2,884	Re: Dansette Viva. Well you made your decision and it looks tidy. Hope you get the results you want. I would always stick to valves, but that's me showing my age Cheers John

21st Jun 2019, 3:59 pm	#18
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Dansette Viva. Hi John, Nothing wrong with valves and in fact if the Viva was equipped with a mains transformer there would be no reason to replace the old amplifier. The new amplifier was tested today and I can report it gives excellent results. The IC used in the Velleman module is the TDA2003. DFWB.

23rd Jun 2019, 6:14 pm	#19
Heatercathodeshort Dekatron Join Date: Jun 2005 Location: Warnham, West Sussex. 10 miles south of DORKING. Posts: 9,147	Re: Dansette Viva. I'm surprised you crossed the floor with this one David installing 'crystal valves' to replace the original valve amplifier. To put a top hat on it you also employed one built on one of those printed circuit novelties. To be honest David I don't blame you. These record players were safe in their day when nobody took them apart and fiddled with them, fitting sockets to play modern equipment etc. Some recent posts have scared me a bit. At least it will be safe and more suited to modern standards. John.