Philco 38-690 tweeter improvement - Printable Version

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+--- Thread: Philco 38-690 tweeter improvement (/showthread.php?tid=1255)

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- wonderwrench - 07-27-2008

Maybe I'm old fashioned but I would leave the tweeters as they are if it we me. I'd try changing the cap as Ron suggested if your not happy with the tweeter performance.

Quote:"I would seriously consider changing the value of capacitor (151) to 4.7 uF, non-polarized. This should help the performance of the tweeters by lowering the crossover frequency to around 4000 cycles, permitting more of the midrange audio frequencies to be reproduced by the tweeters, as well as the high end."

My cents

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- Dave Slusarczyk - 07-27-2008

I do agree with you Bill. I am looking at all options. I will certainly do as Ron suggested.

I must confess as I do some comaprisons and also turned the bass and treble up to max at times, as Ron eluded to and it does sound quite good. I find that on different stations and different songs its performance changes somewhat. I am not blaming the set for this at all.

I just came back in from the shop and am strongly considering leaving it as it is.

Dave

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- wonderwrench - 07-27-2008

Dave Slusarczyk Wrote:I do agree with you Bill. I am looking at all options. I will certainly do as Ron suggested.

I must confess as I do some comaprisons and also turned the bass and treble up to max at times, as Ron eluded to and it does sound quite good. I find that on different stations and different songs its performance changes somewhat. I am not blaming the set for this at all.

I just came back in from the shop and am strongly considering leaving it as it is.

Dave

You must be lucky as I have only 3 local stations that play music and 2 are Spanish stations. The recording quality is very low, besides Spanish music is not my bag. The 3rd is a university station run by the students and they play stuff that I can not even identify. Oh and as I said before many AM stations only go to 5 or 6 KHz so you tweeters may do nothing when listening to them.

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- Syl - 07-28-2008

Dave Slusarczyk Wrote:Afternoon Syl,

I am contemplating insstalling "whizzers". Can one purchase "whizzers" from a supplier?? I do not mind making my own but would prefer purchasing manufactured ones.

How about the speaker "caps"?

Thanks,
Dave

Hi Dave,

Yes, I suppose you can buy whizzers and dust caps online.

Dust caps here, but I can't find whizzers anywhere:
http://www.partsexpress.com/webpage.cfm?webpage_id=3&CAT_ID=48&ObjectGroup_ID=827

I do have a few whizzers on hand but I suspect shipping would be expensive as it needs to be shipped in a small box.

Syl

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- Dave Slusarczyk - 07-28-2008

GOOD NEWS!!

Well guys after digging around in the power supply chassis a little more last evening I found and repaired a problem. As I had stated this set was previously restored---very well I might add. Outstanding solder joints and routing etc. With that said I found a 1K resistor, for whatever reason, in the chassis that essentially bridged across one of the field coils for the tweeters. I removed it and now it plays even better! I am very pleased !!
I am at a loss as to why whomever did the restoration would have installed that resistor. It is not on the schematic. I have scratched my brain trying to make sense of it.

Plays great now!

Happy in Louisiana!
Dave

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- BDM - 07-28-2008

Congrats!

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- Ron Ramirez - 07-28-2008

Way to go Dave...congratulations, enjoy a truly great radio.

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- Dave Slusarczyk - 07-28-2008

Thanks Guys for all your insight and expertise!! Your assistance did not go unapreciated.

Dave

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- Syl - 07-28-2008

Dave Slusarczyk Wrote:GOOD NEWS!!

I have scratched my <b>brain</b> trying to make sense of it.

I hope you mean _head_...;)

Great news indeed!

Syl

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