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Found today in the local Goodwill. - Printable Version

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Re: Found today in the local Goodwill. - DCASAZZA - 01-19-2009

Wow, kinda like stone-age , meets space age. Sort of. By the way, some advise for those thinking of noodling around with surface mount components. be sure to use silver solder. The use of regular 60/ 40 will leach the conductive plate right off the ends component rendering it useless. Silver solder needs to be a bit hotter of course so get in and out of that task quickly.

Re: Found today in the local Goodwill. - gary rabbitt - 01-22-2009

Hi Dave,
Thanks for the advice on the surface mount items.
Right now, I have the unit transmitting sound from a small cassette player, coupled through an old output transformer. Sounds ok, and I think if and when I rebuild the cartridge, it should sound fine. If I build a preamp I may go with some vintage transistors and standard parts, not sure yet.

Adding an AUX input, (no worries, no holes will be drilled Icon_smile ) I may need some sort of better matching to the tube, or sound shaping device. The music I played had a wide range of frequencies, compared to what a 78 record would have. I think my next test would be to play some period music thru it.

Doug, as far as the antenna, the frequency didn't seem to drift at all when I put my hands around the player, or touched the antenna itself.. I looked at the diagram and seen the antenna symbol, but it was not routed to the AC cord , a far as I could see.
The original rubber cord was a 2 conductor cord, and no indication it had any coupling to the cord as a carrier current system would have.

The antenna lead that comes out of the chassis looks like the original rubber coated wire, but obviously someone added the striped wire, and carpet tacks you see. Could one of these transmitters have had a loop instead of coupling to the cord?

OK I need to go, but thanks for your inputs and help as always Icon_smile
Gary

Re: Found today in the local Goodwill. - Howard R Stricklin - 02-19-2009

"You may want to try using a input line matching transformer"


What is a "input line matching transformer" ? I have the same turntable and would like to run a mp3 player or fm tuner
(pilotuner) threw it . what else would i need to set this up ? and what other types of transformers are workable ?

Re: Found today in the local Goodwill. - gary rabbitt - 02-20-2009

Hi Howard,
Others can tell you better than I can about a matching transformer.I am not good at impedance matching or things like that.
I figured the crystal cart would behigh impedance, maybe a frw hundred ohms and the input from an mp3 or tape device would be a lot lower.

What I did was go to the junkbox, and try some of the little audio type transformers I had. An audio output transformer worked for me, somewhat. There was a little distortion in the audio. I don't know if that's from the tape player I used, or the wrong match. or maybe other parts in the RP-1's circuit.

I am going to put the cartridge rebuild on hold for now, and get back to it later. At least for now, I know the unit operates and does what it's supposed to do.

Anyone else have some info on what to use for a matching transformer on this set?
I believe Howard and I have the same version, the code 123

The code 123 has a coupling cap (30pf)from the RF coil to the AC line. It also has only one line filter cap (.01 ) in the bakelite block, while the code 122 has two.

Take care,
Gary.

Re: Found today in the local Goodwill. - radiorich - 02-20-2009

Hello Gary ,
this topic on the phono is some good reading.
Rich
P.S. sly that was nice littele preamp you built

Re: Found today in the local Goodwill. - Howard R Stricklin - 03-08-2009

http://www.radioshack.com/product/index.jsp?productId=2103254&tab=features

will this work ?

Re: Found today in the local Goodwill. - Howard R Stricklin - 03-22-2009

Im looking for a small audio transformer to boost the sig from my RP-1 to my radios .
would the transformer from an old set of koss head phones work ?

or would this do ?
http://www.radioshack.com/product/index.jsp?productId=2103254&tab=features

The sig is strong but garbled on all my radios .

Re: Found today in the local Goodwill. - Howard R Stricklin - 07-12-2009

Found this on ebay for 20 $ ...42 RP-2 ....Cartridge is shot but it broadcasts ...
New caps on the way ....This one broadcasts at the 1700 range on the dial ...
Yet i can find no info stating philco made versions that broadcast from the higher end of the dial .

Note from site admin: Sorry, but the photo which was attached to this post is no longer available.

Re: Found today in the local Goodwill. - Howard R Stricklin - 07-12-2009

..

Note from site admin: Sorry, but the photo which was attached to this post is no longer available.

Re: Found today in the local Goodwill. - Arran - 07-14-2009

DCASAZZA Wrote:Wow, kinda like stone-age , meets space age. Sort of. By the way, some advise for those thinking of noodling around with surface mount components. be sure to use silver solder. The use of regular 60/ 40 will leach the conductive plate right off the ends component rendering it useless. Silver solder needs to be a bit hotter of course so get in and out of that task quickly.

It would be hard to avoid using silver solder, at least the silver bearing type, it seems to be what most of the stores carry. I will take good old 60/40 tin lead any day, this paranoia about lead has gone too far. Now they are having trouble with tin whiskers forming between joints, deadly in air or space craft. What do they think you are going to do, start licking circuit boards between meals? As for the environmental hazard, lead comes out of the ground in the first place.
Best Regards
Arran