Dansette 50 HiFi r/player with Dansette HiFi Mark II amp for stereo, early 1960s

[Al (astral highway)]

I've finally tracked down and ordered a suitable replacement for the volume pot of the record player, as well as for some out-of-spec resistors and some other tone control elements...

I'm looking forward to doing these remaining fixes on the record player soon, before turning my attention to the amplifier!

[antony07]

So this is the original cartridge, Thinking to go with Ed's recommendation of the BSR SC11M

[Al (astral highway)]

Yes, there’s a good one complete without stylus on EBay for just under £39.

Just to be clear, Antony and I have decided to avoid cartridges needing an additonsl pre-amp to be built, partly for the sake of authenticity.

A quick sub of a good cartridge borrowed from another set showed that the record player will have a lovely volume once a suitable permanent cartridge is in place.

(Meanwhile I’m just fixing be tone controls and a few remaining minor points )

[antony07]

So a quick update, I went over to Al's to see the results of the more electrical work he's done on the Dnasette Hifi to improve the audio output, all I am going to say it is amazing... I'll let him explain

[Al (astral highway)]

Originally Posted by antony07

So a quick update, I went over to Al's to see the results of the more electrical work he's done on the Dnasette Hifi to improve the audio output, all I am going to say it is amazing...

Thank you, Ant! I'm really chuffed with the results of the electronic restoration that I've done. I will post an update detailing everything in due course.

Who would have thought that just 8W could fill a room so beautifully?

I can't wait for the new cartridge to arrive!

I'm delighted that you're so happy with the results!

[Al (astral highway)]

Progress! I've electronically restored the separate Hi-fi amplifer. (To refresh your memory, this is a double restoration of the Dansette 50 record player and its matching, separate amplifier. I'm restoring them for someone who gave them as a present to his girlfriend for Christmas.)

This is a very high-speed write-up (I have to smash this post out in literally 20 mins, so please excuse any errors!) and a link to a rough YouTube video I just made. And I mean 'rough!' But I thought better to have something on the record than miss an opportunity.

https://youtu.be/B67BKwtKhds

First, I checked the mains transformer and output transformer and both were fine. Phew! But as I looked around, the set looked more and more in 'interesting' condition.

The PBC was flow-soldered, but the connections to it were made manually and were scruffy and poor.

Wires hadn't been pre-twisted or tinned and there was stray individual strands of wire, both in the valve heater jump leads and in the main connection from the tone controls (signal pathway). These could easily have caused a short and nobody had noticed. I wonder if this is because the set was finished on 21 December (1964) so just before Christmas, and in an hurry?

The PCB had broken tracks and missing pads, especially around the big electrolytic, which someone may have tried to remove. I repaired the pads with copper washers and the tracks with soldering braid.

The whole board had been washed with something like shellac, which was a gloopy mess. I removed completely and with some effort with Isopropyl alcohol and a toothbrush.

I remade the entire wiring of the set with multi-stranded thicker gauge wire.

In the process, I shortened unnecessarily long wire runs, including:

• to the output transformer
• from the mains transformer
• in the signal path

I re-routed mains wiring around the chassis in tight twisted pairs. Originally the wires were single and hanging around.

This had a poor impact on hum, which my re-wiring remedied entirely.

I found an o/c resistor (180R) in the cathodes of the output valves. I replaced several other out of spec resistors, all with modern metal oxide types.

I replaced the coupling capacitors (47nF) from the concertina phase-splitter to the grids of the output valves.

I reformed the original electrolytics, which I have kept intact.

There were dry joints around the tone and volume controls, and some passives had come unsoldered. I remade these. I shortened wires in the signal path and further lowered hum by putting in a short section of coax where a wire had been unscreened in the signal pathway.

That's it for now! There's not much written on these sets so I may get round to doing a little guide to them.

Pix before...

[Al (astral highway)]

Pix after:

You can clearly see the repaired PCB with its new jump wires for the heaters, nice and short, and also the new twisted-pair mains wired routed around the chassis, and the shortened pick-up wire, also shortened and routed around the chassis.

Ant has ordered a stereo cartridge, so the next step is to install that and test the whole system in stereo for the first time.

Finally, I forgot to credit one of the invisible heroines of production, a certain LINDA, whose name is written in pencil beneath the loudspeaker. I wonder if she assembled the chassis into the cabinet?

P.s. the only 'changes' I've made to the original design are to add bleeder resistors across the electrolytics as I was working on both sides of the chassis, and a new (well, vintage, from my collection) pilot bulb holder to replace the old one, which was kaput.

[CambridgeWorks]

Al, you are a star. NO, 5*! I am certain Antony07 and his girlfriend will be delighted.
It must give you tremendous pleasure to do this for them.
Rob

[Al (astral highway)]

Originally Posted by robinshack

Al, you are a star. NO, 5*!...
It must give you tremendous pleasure to do this for them.

Thank you, Robin! That means a lot to me!

Ant’s a brilliant person, really friendly and with amazing intentions. He’s also a perfectionist, a classic car restorer and also does amazing furniture / cabinet refurbs, including on his Dansette collection. There couldn’t be a better person/ couple to be doing this for...

[antony07]

Originally Posted by robinshack

Al, you are a star. NO, 5*! I am certain Antony07 and his girlfriend will be delighted.
It must give you tremendous pleasure to do this for them.
Rob

I am more than delighted Robin, I can't wait to give the completed set to my girlfriend for the final time and she can now start to use it as it deserves and also rebuild her vinyl collection again!

Its funny how I found Al on here and he happens to live round the corner, top bloke!

[Al (astral highway)]

New cartridge arrived -BSR SC11M - thank you, Edward, for your recommendation - and installed on the record player. It sounds wonderful. The headshell is much lighter than originally, so one Euro is in service as a counterweight for the time being.

After a bit of improvising, I've adapted the original aux panel to have a phono out connection to the amplifier. The panel is in poor nick, with broken-down insulation on on of the sockets. I adapted by using the tape-in socket as phono-out for R channel.

But finally, both the amp and record player are working and there's pretty decent stereo imagery. I can't wait for Ant to hear the combo in action!

[Edward Huggins]

New cartridge arrived -BSR SC11M - thank you, Edward, for your recommendation - and installed on the record player. It sounds wonderful. The headshell is much lighter than originally, so one Euro is in service as a counterweight for the time being.

Oh dear, don't use a coin - you'll get an outcry here! All you are doing is adding mass.
Just re-set the tone arm tracking weight. Do you know how to do this?

[Al (astral highway)]

Originally Posted by Edward Huggins

Oh dear, don't use a coin - you'll get an outcry here! All you are doing is adding mass.

No need for any panic, Edward - I had to improvise to test the new cartridge installation (the old one was mono) as well as the record player, in combo with the amp for the first time .

The needle would have just skittered all over the record I was using. It's mine and I'm not too precious about it. Actually , now I recall, it wouldn’t even have skittered- the tone-arm would just have been un-naturally raised, like one side of a suspension bridge.

Also, the weight was there in the first place - the very old - probably 1964 original- cartridge was riveted to a hefty lump of metal under the headshell. I'm just adding back what was there before. It doesn't look elegant, but the forces are the same.

(I'm also going to be a cheeky pedant, it's weight, not mass...)

Originally Posted by Edward Huggins

ust re-set the tone arm tracking weight. Do you know how to do this?

The tone-arm on the integral Garrard player is simple, plastic and doesn't have (that I can see) any way of reducing the leverage by sliding or twisting an integral tone-arm tracking weight. I'm of course familiar with more sophisticated models from my teens onwards that did/do use such methods.

[julie_m]

Originally Posted by astral highway

(I'm also going to be a cheeky pedant, it's weight, not mass...)

The mass of the tonearm system (meaning, everything the other side of the crystal / ceramic sensing elements from the stylus cantilever) is important, though. Let the mass of the stylus and cantilever assembly be m, and say it's moving with speed v. It is going to transfer its momentum to the rest of the system, whose mass is M; that will set the rest of the tonearm system moving with a speed v * m / M. In a perfect world, it should be standing perfectly still (in a perfect world, the record groove would be a perfectly straight line, so the tonearm would not be traversing anywhere). To approximate that as best we can, we want M >> m.

So it's better to maintain balance, if a cartridge replacement takes it beyond the range of adjustment provided, by adding mass (and therefore weight) at the cartridge end, than by removing weight from the other side of the fulcrum.

[Al (astral highway)]

Originally Posted by julie_m

So it's better to maintain balance, if a cartridge replacement takes it beyond the range of adjustment provided, by adding mass (and therefore weight) at the cartridge end, than by removing weight from the other side of the fulcrum.

That's an illuminating insight, Julie. And reassuring to have confirmed. Thank you

User warning: when using a Euro, the value of your weight can go up and down

[Al (astral highway)]

It was wonderful this Sat evening, when Ant came by with his girlfriend to collect the record player and amplifier.

I demonstrated the restored pair, working together for stereo reproduction, with a record printed in 1967 (three years younger than the sets).

It was a delightful event in the timeline of getting to know Ant,bringing the sets back to life, and meeting their future owner/ custodian, who took them home to enjoy.

[Kentode]

Well done Al, that's brilliant!

You've been doing this restoration for about six weeks, which shows great dedication.

I'm sure that this system will used and loved for a long time. What a credit you are to the forum.

P.S. In post #41 you mentioned that you had sourced a potentiometer, can you say where from?

[Hartley118]

Originally Posted by Edward Huggins

Oh dear, don't use a coin - you'll get an outcry here! All you are doing is adding mass.

An outcry from whom? As Julie points out, head mass can be important and a coin is a useful calibrated mass. 1 euro = 7.5g; 1p = 3.5g. you can always hide it in the headshell

The audio effect of insufficient head mass is to increase the LF resonant frequency between cartridge compliance and head mass. If the new cartridge has lower mass than the old one, then it's the mass that needs correcting, not just the tracking force.

Delighted that it all works Al.

Martin

[Al (astral highway)]

Originally Posted by Kentode

Well done Al, that's brilliant!

You've been doing this restoration for about six weeks, which shows great dedication.

I'm sure that this system will used and loved for a long time. What a credit you are to the forum.

Thank you, Ken! That's wonderfully generous feedback and means a lot to me. Yes, I hope it will survive 50 years+!

If I can make the time, I might upgrade the only circuit diagram that seems available online with some reference voltages and missing component values...

Originally Posted by Kentode

In post #41 you mentioned that you had sourced a potentiometer, can you say where from?

There don't seem to be many sources of logarithmic pots with integral, mains-rated switches - I was quite surprised - but I located a 2.2Meg linear one at Cricklewood Electronics in the end. (Original is 1meg log, but the mains switch isn't a common feature from most sources) Have you heard of them or used them before?

Cheers!

[Al (astral highway)]

Originally Posted by Hartley118

An outcry from whom? As Julie points out, head mass can be important and a coin is a useful calibrated mass. 1 euro = 7.5g; 1p = 3.5g. you can always hide it in the headshell


Delighted that it all works Al.

Hello Martin, thank you!

And also for adding that factoid! Incredible knowledge! I knew it was sub 10-grammes, but I didn't have a scale calibrated accurately enough to see by how much, so it's good to know the precise figure.


Cheers!