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 NEW  Bruce Heran outlines the details and construction of his simple DIY 6DJ8 (ECC88) Tube Hi-Fi Headphone Amplifier Project.

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 Post subject: FM Tube Radio
PostPosted: 20 Oct 2010, 13:10 
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Joined: 14 Feb 2010, 13:13
Posts: 617
Location: Lisbon, Portugal
Hi!

I would like to build an FM tube radio (not super regenerative). Do you have a schematic, or know where to get a kit? Coils and IF transformers are not a problem (can do them).

Cheers in advance!
Miguel


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 Post subject: Re: FM Tube Radio
PostPosted: 20 Oct 2010, 13:35 
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Joined: 31 Dec 2008, 15:34
Posts: 333
Location: Denmark
Hi Miguel

What about this simple one ?
http://www.somerset.net/arm/radio_pictu ... _fm_jr.pdf

or this one:
http://www.somerset.net/arm/reprints/fm_tuner_2.jpg

both found here:
http://www.somerset.net/arm/fm_only_lowtech.html

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Kramme


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 Post subject: Re: FM Tube Radio
PostPosted: 21 Oct 2010, 16:57 
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Joined: 05 Jan 2009, 05:18
Posts: 43
HT Performance wrote:
I would like to build an FM tube radio (not super regenerative). Do you have a schematic, or know where to get a kit? Coils and IF transformers are not a problem (can do them).

Why not find a vintage tuner in need of restoration? It will be far cheaper, and most likely better performing than building from scratch. Ebay usually has a few un-restored Leak Trough Line tuners at sensible prices. The schematics and servicing info can be found online too. For a self-build challenge you could try designing and building a stereo decoder using tubes to use with your tuner.


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 Post subject: Re: FM Tube Radio
PostPosted: 22 Oct 2010, 08:56 
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Joined: 14 Oct 2008, 17:35
Posts: 901
Location: Dartmouth, Nova Scotia
I have an old fleet wood console that I stripped for the amplifier stage, but I plan on using the rest to create an AM/FM tuner, everything is there it just needs to be rewired.

I suppose if you want a tuner with tube sound you could just find a good SS tuner and change the output amplifier into a single stage tube output, I plan on doing this with an LXI tuner I have that has good overall sound.

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My Mini 12AU7 Tube Preamp, Pioneer SX-D7000, JVC XL-V221BK, JBL L80T, DCM TF700


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 Post subject: Re: FM Tube Radio
PostPosted: 23 Oct 2010, 12:06 
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Joined: 14 Feb 2010, 13:13
Posts: 617
Location: Lisbon, Portugal
Well, I found this Dynaco... http://www.curcioaudio.com/Dyna%20FM-3%20Mnl.pdf

Quite a job!


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 Post subject: Re: FM Tube Radio
PostPosted: 27 Oct 2010, 19:37 
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Joined: 14 Feb 2010, 13:13
Posts: 617
Location: Lisbon, Portugal
Does anyone own the Dynaco FM-3 tuner? Or maybe any personal reviews? I´m so tempted to get an old one for restoration... Good pictures here: http://www.akh.se/audio/dynaco/fm3.htm

Cheers!
Miguel


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 Post subject: Re: FM Tube Radio
PostPosted: 30 Oct 2010, 15:21 
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Joined: 14 Feb 2010, 13:13
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Location: Lisbon, Portugal
Well this one was hard to find. Looks good, but schematic has repeated stages and no IF transformers? I little bit confusing to me...

Check it here: http://philsvalveradiosite.co.uk/philsvalveradiosite/valvevhffmpulsecountingreceiver_1.htm

The guy says it works like a charm.

I wonder if 6N1P Russian tubes can be used in place of ECC88´s ??? The 6N1P´s are so cheap!!!

What do you think? It is also possible to add a stereo decoder, as this circuit has a pulse counter.

YouTube Video: http://www.youtube.com/watch?v=wo-DJLjY9oI&feature=channel



Miguel


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 Post subject: Re: FM Tube Radio
PostPosted: 31 Oct 2010, 17:08 
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Joined: 05 Jan 2009, 05:18
Posts: 43
Back in 2008 I wrote the following about upgrading one of my Troughlines from ECC84 to ECC88.

http://saunby.blogspot.com/2008/08/expe ... -line.html

I've probably still got a few ECC88 and E88CC stashed away - good used examples these valves aren't as scarce as many Ebay sellers suggest. Tektronix scopes were full of them, and these are long life valves. Though if PCC84 will work, then these are often very cheap.


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 Post subject: Re: FM Tube Radio
PostPosted: 14 Nov 2010, 12:50 
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Joined: 14 Feb 2010, 13:13
Posts: 617
Location: Lisbon, Portugal
Hi!

From many research, I decided to give a try on this one as a start.
It may not be a Hi-Fi receiver, but very easy build for sure.
It offers the super-regenerative + super-heteroyne type.

Check here:
Image

Just one single 12AT7 tube! Typical application here:
Image

Cheers,
Miguel


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 Post subject: Re: FM Tube Radio
PostPosted: 15 Nov 2010, 16:54 
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Joined: 14 Feb 2010, 13:13
Posts: 617
Location: Lisbon, Portugal
As you already may noticed, this type of circuit was used on commercial sold FM receivers. This particular circuit uses only one single IF coil. This is not the regular super-regenerative "poor" performance receiver type!

It may look like a nightmare for many people, but it is not. Of course I would like to have a genuine IF coil, but they are so hard to get. So here is a page, that clearly shows how to build IF coils for tube receivers, with some goods you may get inside your house, or just the nearest hardware store.

Check here: http://www.sm0vpo.com:800/blocks/if-txfmr_tube_00.htm

I´m currently running a Gainclone amplifier for a Christmas gift, so I may not have all the time required to dive into this lovely project,

In fact, I don´t even have a 12AT7 / ECC81 tube... I´ll keep posting for you, I really believe in success! :)

Cheers,
Miguel


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