Tivoli Model ONE vs. KLH Model TWENTY ONE

[tiefbassuebertr]

Tivoli Model ONE vs. KLH Model TWENTY ONE
I need the schematic of Tivoli Model ONE. Who can help?

Here some URLs and attached pics - the KLH model 21 looks in much higher quality standart than Tivoli Model ONE - at least in the aera of the RF-IF unit (variable capacitor e. g.)

URLs to Tivoli Model ONE
Tivoli speaker
Tivoli Model 1 FM aerial connector replacement ?
Tivoli Model One Aux Input Modification
photos for albums/Audio/Tivoli Model 2
http://www.datasheetcatalog.org/data...ps/TEA5710.pdf

URLs to KLH Model TWENTY ONE
klh model 21 with problems... - The Classic Speaker Pages Discussion Forums
The KLH Model 21 re-invented - Tivoli System Henry Kloss Model One AM/FM Radio ( Walnut) - Epinions.com
KLH Model 20 Plus - The Classic Speaker Pages Discussion Forums
Vintage KLH Model 21 AM/FM radio circa 1970's - eBay (item 260720654378 end time Jan-18-11 18:14:03 PST)

[tiefbassuebertr]

Now I have my own schematic drawing - the main feature is the "feedforward correction" respective equalizing in front of the power amp input.
This contains no DSP technique but four analouge operational amplifier sections. Similar to
Pfleid Loudspeakers
but not similar to ace bass correction
Audio Pro - Sound of Scandinavia
After carried out repair work by some devices this service now is an easy task for me (only for Tivoli Model "ONE") - but only when I have several devices of the same model at the same time.

The measures frequency response has enhancements in the aera between approx. 100-200Hz so as between 11-14 KHz on axis (attenuated in great value off axis)
The medium range (midrange) arround 2-3 kHz is attenuated approximately 6db

Flicker noise while turn on by tuning select knob is the chief defect (internal contact trouble in the sliding contacts of variable capacitor/polyvaricon - after solder out and completely disass'y easy to clean - but first thing (so as the follow assembly procedure is too complicated as I suggest here this for normal technical persones.
Next Step is finding out a variable capacitor in same sizes, but only for FM (without AM). Then the reliabitity must be much more higher.
Must users don't need AM aera - so I think.

[joshrd]

Could you provide me with a schematic? I am building a radio and someone said that TIVOLI are quite good.

Thank you

[panxtiv]

After several years using this nice radio, the big problem associated to the tuning capacitor varycom emerged and is impossible to use FM .
I decided to transform it in one FM receiver using a classical and better air two gang capacitor ( 2x 20 pF). For the moment I will receive in a few days this unit VARIABLE CAPACITOR TWO GANG JACKSON BROS from Ebay and I will try to incorporate it in the box, non easy task due to the size.
Is there other alternative to find a better and compatible capacitor to maintain also AM band ? Any suggestion related to this modification is welcome .

[tiefbassuebertr]

Originally Posted by panxtiv

After several years using this nice radio, the big problem associated to the tuning capacitor varycom emerged and is impossible to use FM .
I decided to transform it in one FM receiver using a classical and better air two gang capacitor ( 2x 20 pF). For the moment I will receive in a few days this unit VARIABLE CAPACITOR TWO GANG JACKSON BROS from Ebay and I will try to incorporate it in the box, non easy task due to the size.
Is there other alternative to find a better and compatible capacitor to maintain also AM band ? Any suggestion related to this modification is welcome .

I don't understand this term:
"the big problem associated to the tuning capacitor varycom emerged and is impossible to use FM"
What exactly is the reason of the failure from your no longer useful variable capacitor?
Mean you the variable capacitor from image two of post #1? This kind of capacitor you will often find in various old fm tuner front ends, produced between 1960 and 1975.

[panxtiv]

In my opinion the varycom capacitor ( 160/ 80 pF for AM and 2x20pF for FM ) included in this radio receiver is not high quality and after 4-5years ( at least in my case ) is damaged , producing terrible noise during the tuning in FM . I do not know if the problem is associated to bad contact between the fixed plates and ground ( rotary axe ... ) or between plates . For the moment I am not considering other causes different to the capacitor.

[panxtiv]

Concerning type of new capacitor in fact I am considering the traditional as included in the second photo corresponding to the Twenty One model. ( Sorry for my english if I include some mistake , in spanish I have not problem )

[panxtiv]

Hello Tiefbassuebert , yesterday I test only in FM my Tivoli One with a new variable capacitor 23+28 pF and is working perfectly without any noise during tuning. Is a little big as you can see in the photos but the diagnosis was correct.
I have a big question concerning the schematic : following the pcb the pin 23 ( FM-Osc ) of TDA 5711T is connected to ground and the radio is operating with one single section of the capacitor .Do you agree with this conclusion and what should be the explanation ,not based in the product especification?

[tiefbassuebertr]

Originally Posted by panxtiv

Hello Tiefbassuebert , yesterday I test only in FM my Tivoli One with a new variable capacitor 23+28 pF and is working perfectly without any noise during tuning. Is a little big as you can see in the photos but the diagnosis was correct.
I have a big question concerning the schematic : following the pcb the pin 23 ( FM-Osc ) of TDA 5711T is connected to ground and the radio is operating with one single section of the capacitor .Do you agree with this conclusion and what should be the explanation ,not based in the product especification?

I don't find the datasheet of the TDA5711T in the moment
have a look to the datasheet of TDA5710T:
PIN23 am rf-I parallel tuned am arial circuit to GND
PIN18 FM OSC
Please do post the datasheet of TDA5711T or at least the application advices/schematic diagram

[panxtiv]

Sorry for the IC indicated , the correct IC used in the radio is Philips TEA5711T
http:// http://www.datasheetcatalog.org/data...s/TEA5711T.pdf

The real schema is not corresponding to the application note from this IC , being used one specific circuit for the RF front end with one dual gate FET ( U72 ) and other components ( SC 1359, 2N 3904, 2N 3906 ...)
With only FM , the radio is working very well with a new air variable capacitor -using one section- ( 10-30 pF), but in any case the modification is critical.