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Wakefield Turntables
06-09-2012, 16:54
I have a dynalab tuner (USA 120V) which I use with a converter to run on my current setup. Does anyone have the contact details of someone that convert it to 240v, I'm also looking at getting a set of balanced outputs installed?? If anyone on the forum can do the mods and wants to make some money I'm more than happy to send it to them.

Thanks

A
Marco
06-09-2012, 16:58
Hi Andrew,

Someone like Nick (lurcher) or Anthony TD could easily make you a suitable step-down transformer, so I'd send either one of them a PM :)

Marco.
Wakefield Turntables
06-09-2012, 17:23
Cheers :eek:
Nevalti
11-09-2012, 14:28
I expect I am showing my ignorance again but USA FM transmissions and UK FM transmissions have a different bias (is bias the right term?). You may need to do more than change the power supply to get it to sound right. If I remember correctly, you will lose quite a lot of top end using a USA tuner in the UK.

I don't know what other countries share the same bias as the USA. Maybe you intend to use it in one of them?
sq225917
11-09-2012, 15:25
Isn't it the band spacing that is different between US and UK?
Wakefield Turntables
11-09-2012, 15:30
I expect I am showing my ignorance again but USA FM transmissions and UK FM transmissions have a different bias (is bias the right term?). You may need to do more than change the power supply to get it to sound right. If I remember correctly, you will lose quite a lot of top end using a USA tuner in the UK.

I don't know what other countries share the same bias as the USA. Maybe you intend to use it in one of them?

Thanks, looks like I might need to get this looked into.


Isn't it the band spacing that is different between US and UK?

Simon, what do you mean by band spacing :scratch:I must admit ive never heard of this so a explanation in nice simple english would be great :D
Ali Tait
11-09-2012, 17:50
Yes, I think it's that the FM frequencies range from 88 to 108 in the UK, as seen on the dial, but the frequencies used in the US are a little different. What does it say on the tuner?

I have no idea if anything else is different.

As for the voltage, it may just mean moving a link on the internal transformer possibly.

The balanced outs might be a bit involved depending on the circuit design.
NRG
11-09-2012, 20:45
I think if its analogue based tuning you should be OK, if digital I think the Americas use odd frequency multipliers and here in the UK even multipliers...so may not work :scratch:
Wakefield Turntables
11-09-2012, 20:50
well i can confirm that it picks things up nice and clear. I'll post some pics tomorrow to see if we can resolve the problem of swapping the power around. :)
NRG
11-09-2012, 20:51
Yep, some googling reveals it should work fine even if tuning is digital.
Wakefield Turntables
12-09-2012, 07:10
Neal,

Thanks mate for taking the time to check that our for me :cool: the tuning is indeed digital.

Andrew
PLINIUS
12-09-2012, 07:57
Isn't it the band spacing that is different between US and UK?
Yes, in both AM & FM which is a problem with many auto-tune devices but the Dynalab has much more tuning versatilety so it won't be an issue.
Wakefield Turntables
12-09-2012, 08:36
Even better news thanks Peter
bobbasrah
12-09-2012, 09:33
Perhaps not the case for this particular machine Andrew, but many of these tunersets have the frequency steps selectable by a jumper, DIP or similar to enable them to be set for different markets.... Just a thought....
sq225917
12-09-2012, 09:53
Andrew, take the lid off and have a look inside, it might be the case that the unit was designed with dual windings on the transformer and all that is required is a little switcharoo of the connections from the transformer. If there's spare wires hanging off the transformer it's likely.
Wakefield Turntables
12-09-2012, 18:53
Right I have take the lid off and tried to produce some clear pics for you guys to examine. :eyebrows: Its looks like the main PCB can be modified to 240v but I welcome your comments. Ive also included a pic of the RCA output stage. I'd also welcome some comments to see if this can be converted at some point to balanced. :cool:
Mr Kipling
12-09-2012, 19:35
I expect I am showing my ignorance again but USA FM transmissions and UK FM transmissions have a different bias (is bias the right term?). You may need to do more than change the power supply to get it to sound right. If I remember correctly, you will lose quite a lot of top end using a USA tuner in the UK.

I don't know what other countries share the same bias as the USA. Maybe you intend to use it in one of them?

It's called de-emphasis". When broadcast, the top-end is boosted and then gets cut in the tuner for a flat frequency response. The Americans use a time constant of 75uS and in Europe it's 50uS. It's a resistor and capacitor in parallel on the output to earth going into the stereo decoder. Some tuners have it switchable.

Kind Regards,
Stephen.
Wakefield Turntables
12-09-2012, 19:50
Stephen you sound like you know what your talking about (no insult meant)!

You made a comment

"It's a resistor and capacitor in parallel on the output to earth going into the stereo decoder. Some tuners have it switchable."

Can you see that occuring on the PCB pix that i've included or would you need additional photos?

A
Mr Kipling
12-09-2012, 20:04
What model number is it?
Wakefield Turntables
12-09-2012, 20:09
THE ft101a
Mr Kipling
12-09-2012, 20:21
Andrew, a little knowledge is a dangerous thing! My technical knowledge isn't as great as I would like, to be honest.

I'm afraid I can't make much out on the photos on my mobile. It would need a circuit diagram.

Looking on the 'net, there are a number of models for Dynalab.
sq225917
12-09-2012, 20:30
The pcb certainly looks like it has been made with 220v operation in mind, but sadly for you 220 and our 240 may be too far apart. Best bet would be a new 240v input transformer that gives the same output as the current one.
Wakefield Turntables
12-09-2012, 21:22
The pcb certainly looks like it has been made with 220v operation in mind, but sadly for you 220 and our 240 may be too far apart. Best bet would be a new 240v input transformer that gives the same output as the current one.

Thats might just be too expensive, its a piece of kit I use every so often so I cant justify the expense.
Mr Kipling
12-09-2012, 21:28
Looking on the 'net Andrew, a 100K resistor on the output and a 750pF capacitor to earth gives the 75uS figure and changing the capacitor to 500pF gives the 50uS.

Haven't found any circuits so far but have found there are at least 5 versions of the 101A.
PLINIUS
13-09-2012, 01:18
Thats might just be too expensive, its a piece of kit I use every so often so I cant justify the expense.
It would appear that the transformer is not dual wound, meaning a new transformer would be needed. If you are happy with the performance using the power adaptor, I would leave it as is. It is a very nice piece of kit:)
Wakefield Turntables
13-09-2012, 07:51
It would appear that the transformer is not dual wound, meaning a new transformer would be needed. If you are happy with the performance using the power adaptor, I would leave it as is. It is a very nice piece of kit:)


Peter I think I would be inclined to agree now that I have taken the hood off and sen what needs to be.
Mr Kipling
13-09-2012, 18:39
Sorry Andrew. Still had no luck with finding a circuit diagram. A bit of interesting read at http://www.fmtunerinfo.com
Wakefield Turntables
13-09-2012, 19:10
Stephen,

No worries mate, I'm still really chuffed you took time out to do a little detective work. A big thanks to you! I think the Dynalab can stay as it is, the
money I was going to spend on mods can go on vinyl instead!

andrew