David Winter DW FM Module V 3.0

[bobhowe]

Hi just received David Winters latest DW FM V 3.0 and this has some new features added . It has 3 modes of tuning 1 is Capacitive that works with the radios tuning capacitor . 2 Local. Oscillator mode this can work with most AM radios with a tuning capacitor or variable inductance tuning in this mode.a magic eye can be used to indicate signal strength . 3 Resistive mode uses a 10k to 50k linear potentiometer . I am going for Resistive mode and use a radio with a gram input there is more information on Davids web site kind regards Bob

[FERNSEH]

Hi Bob,
this new FM converter might well be the device that could be the saviour of radio collecting. Just like the SRF Arora and Hedghog 405 line converters are to collecting and using 405 line television sets.
The tuning capacitor mode of tuning can be the best method for most radios but make sure that the local oscillator in rendered inactive.
Some time ago I modified a Bush DAC90A to in incorporate the earlier David Winter FM module. The modifications involved the fitment of a three way four pole wave-change switch. Now that the latest FM converter has a potentiometer tuning facility it might be possible to fit the FM tuning pot to the tuning capacitor shaft. Use the exiting two way wave-change switch.

We look forward to Bob's comments about the new FM module.

DFWB.

[bobhowe]

Hi David i second your comments that this could be the saviour of radio collecting as now MW sets are now ornaments having at best 2 stations Talk Sport and Radio 5 live . My DAC90A with the early David winter version module is still performing great As you say you did the conversion with the three way switch is some achievement on a DA90A with the limited space and bracket that the wave change switch is part of the dial chord tuning as well . The potentiometer mode can be adjusted to what way the start to finish the FM tuning scale as well . kind regards Bob

[System A]

Hi Bob,
This is an interesting topic, I will have to purchase one of these for my DC 90 A as there isn't much broadcast . I will follow your progress Bob and David with great interest.
King regards.
Gary.

[RoundyMooney]

These are great little devices if sympathetically installed, in particular the newer versions with the better chipset (2.2).

DW seems to pursue a policy of developing and improving them and for me the 2.2 is perfect, even if it does need retuning on powerup each time that's a minor inconvenience.

The cost is very fair as well-but for those of us who'd buy twenty at a time, we'd always welcome a further reduction!

This module is a little more expensive, but that's absolutely understandable-it does more!

I designed a board to provide the FM-DWs with a isolated and regulated dc supply (probably unnecessary in itself), LED indication (I usually backlight the dial scale accordingly), and a dual rail op amp to boost the audio-this is very much needed on short superhets for example.

This module, along with the others I make, goes in the audio line to the volume control, and will therefore deliver FM audio output regardless of bandswitch position. I usually fit a sympathetic looking latching pushbutton.

Nonetheless I found in the past that residual local oscillation or radiation affected the FM DW, so I ground the variable capacitor using a 1k resistor when the module is active, this avoids tuning "jumps" if the bandswitch is operated when FM is in use.

The AM Saver works fine, but I never bothered with it-I can,, frankly, build these for less, and they provide more refinement in terms of audio amplification.

Finally, I have noted some RFI when the module is powered-so it is only energised when needed.

[bobhowe]

[
Hi Thanks for reply i have 3 DW modules version 1.0 is fitted to a Bush DAC90A that has the Excellent Ed Dinning Auto Transformer and this is a FM only set and it can be left for weeks and when it is powered up the last station it was tuned in it plays perfect . Version 2.2 is on the work bench on a scrap DAC90A chassis( for using the tuning capacitor ) and is connected to the PU input on a Bush VHF 61 this is my workshop radio until i can find a suitable radio . Ekco AC97 ? . Version 3.0 is my latest kind regards Bob

[RoundyMooney]

Funnily enough, the first iteration of the board above went into a DAC90A for the mother in law. She would run it for around six hours a day, and is happy to tweak it once when it warms up to lock in her station of choice (AFC works well on the newer ones).

Works very well. I didn't go the auto trafo route, but fitted a capacitive dropper and utilised the space left over to fit a 9v transformer to power the board.

Has worked flawlessly.

I'd be very interested to hear how the new module works.

[bobhowe]

Originally Posted by System A

Hi Bob,
This is an interesting topic, I will have to purchase one of these for my DC 90 A as there isn't much broadcast . I will follow your progress Bob and David with great interest.
King regards.
Gary.

Hi Gary got a spare Bush DAC90A chassis this would be ideal for a FM only radio and keep the original chassis STD kind regards Bob

[bobhowe]

Originally Posted by RoundyMooney

Funnily enough, the first iteration of the board above went into a DAC90A for the mother in law. She would run it for around six hours a day, and is happy to tweak it once when it warms up to lock in her station of choice (AFC works well on the newer ones).

Works very well. I didn't go the auto trafo route, but fitted a capacitive dropper and utilised the space left over to fit a 9v transformer to power the board.

Has worked flawlessly.

I'd be very interested to hear how the new module works.

Hi temporary set up the V 3.0 FM module on resistive mode and it works well but is very sensitive in tuning . David Winter says the potentiometer has to be in perfect condition with no jitters so that could be the problem so i will have to try some different potentiometers . This Module is going to be self contained and put in an external enclosure and be used with a radio with a gram pickup input here is a picture of the V 3.0 playing through the gram input on a BUSH FM 61kind regards Bob

[RoundyMooney]

Thanks Bob, good to see your experimentation paying dividends.

You probably know this, but be mindful of static discharge (ESD) with these guys. I strap up until they are soldered to the board and grounded.

The key advantage of resistive tuning is that lead position makes no difference!

[Steve_Bell]

As you are making a stand-alone unit, have you thought about a multiturn potentiometer? 5 and 10-turn pots are available. Resistance values typically available are 100R to 100K ohms

[bobhowe]

Originally Posted by Steve_Bell

As you are making a stand-alone unit, have you thought about a multiturn potentiometer? 5 and 10-turn pots are available. Resistance values typically available are 100R to 100K ohms

Hi Steve yes i am going to make a stand- alone unit. I was round to see Ed Dinning last Sunday and he did suggest to use a multi-turn pot as well the resistance range for this module is 10K to 50K linear . Kind Regards Bob

[bobhowe]

Originally Posted by RoundyMooney

Thanks Bob, good to see your experimentation paying dividends.

You probably know this, but be mindful of static discharge (ESD) with these guys. I strap up until they are soldered to the board and grounded.

The key advantage of resistive tuning is that lead position makes no difference!

Hi thanks for the advise of static discharge i purchased a static mat and wrist strap while i was waiting for the 1st DW module to arrive.If you look next to the Fluke DVM there is a earth connection on the grey anti static mat . Next step is to obtain a multi-turn pot as Ed Dinning and Steve Bell have suggested kind Regards Bob

[Freya]

I have been fitting Temic 1890 FM modules which were around in abundance, these have varicap tuning and when coupled with a multiturn 10k pot for tuning, can be coupled to the existing radio tuning using a small pulley with a modified dial string.

[John G8MWF]

I have read the above comments with great interest and the biggest point that came over is how this modification makes the radio a useable item now that AM is virtually dead.

My intention is to install FM-DW 3.0 into a DAC90A that will "reside" in the living room and be a daily user. I have yet to decide if I will use the AM option.

I have had a quick look at the installation instruction sheet and I am starting to absorb the details. Installing a module of this type into a live chassis will take a little research!

Without re-inventing the wheel I would like to follow someone else's, if they are willing to help, procedures on a DAC90A.

If possible I do not want install additional transformers and provide the power from the existing setup - has this already taken place or am I going down the wrong path?

Thanks for looking.

John

[bobhowe]

Hi John my advise is without upsetting purists is to make the DAC90A FM only as you say MW is dead only 1 station where I live not worth the time and hassle to have MW as well. I used the Ed Dinning Auto Transformer to reduce heat and it has a 6.3V tap to power the dial lamps and this is used to power the David Winder as well. Please read David Winters' advise about static electricity and the tuning capacitor with no faults and the radios amplifier is serviced. I have a DAC90A with the MK1 and MK2 module and a have a MK 3 module that is an ongoing project. Kind regards Bob

[RoundyMooney]

Hi John.

The board I use (see my post further up the thread) works very well with a little 6 or 9v transformer. The 9v option actually works better as it provides more headroom for the op amp AF preamp which I've incorporated into my design.

These transformers can be got for a euro/quid or two from the usual Chinese sites, and can also be used to provide LED backlighting for AC/DC radios.

I have noted the latest batches of DW2.3 modules seem to have a greater degree of inter station noise, almost like modulation hum-I've yet to determine if that's a local issue or not.

I have yet to try a 3.0 as I have no need of it, but I do have a nice big Murphy console here that I might fit one on-purely to drive the magic eye.

Originally Posted by John G8MWF

I have read the above comments with great interest and the biggest point that came over is how this modification makes the radio a useable item now that AM is virtually dead.

My intention is to install FM-DW 3.0 into a DAC90A that will "reside" in the living room and be a daily user. I have yet to decide if I will use the AM option.

I have had a quick look at the installation instruction sheet and I am starting to absorb the details. Installing a module of this type into a live chassis will take a little research!

Without re-inventing the wheel I would like to follow someone else's, if they are willing to help, procedures on a DAC90A.

If possible I do not want install additional transformers and provide the power from the existing setup - has this already taken place or am I going down the wrong path?

Thanks for looking.

John