Well guys and gals, its finally done! I am running for the first time so I have KT 120 tubes installed for now. I want to make sure everything is ok and stable before I put in the KT 150 tubes.
Shannon Parks wrote:Nice work! What speakers are you driving with them?
Shannon
justinsweber wrote:Stupid question...
Is there any place where the modifications that are needed to the Eiclone to exploit KT120/KT150s are documents? I couldnt find.
Ive built 4 Eiclones and love the amps... but I dont think I have enough fill current to light them up and wonder what the transfer used is spec'd at?
Thanks in advance.
Shannon Parks wrote:justinsweber wrote:Stupid question...
Is there any place where the modifications that are needed to the Eiclone to exploit KT120/KT150s are documents? I couldnt find.
Ive built 4 Eiclones and love the amps... but I dont think I have enough fill current to light them up and wonder what the transfer used is spec'd at?
Thanks in advance.
Justin, there's just the parts list mod on page 7 of the manual. Make those changes and use the scary 900VCT Edcor mentioned elsewhere on these threads with the 100W OPTs. Bias at 75% idle. I don't really support or promote it though, out of liability concerns.
Shannon
justinsweber wrote:Stupid question...
Is there any place where the modifications that are needed to the Eiclone to exploit KT120/KT150s are documents? I couldnt find.
Ive built 4 Eiclones and love the amps... but I dont think I have enough fill current to light them up and wonder what the transfer used is spec'd at?
Thanks in advance.
justinsweber wrote:Thank you for the info... few more questions.
Looking at the parts list.
Power transformer for a 120V, 60Hz. line to 900V (450-0-450) at 300mA and 6.3V at 6A.
Ouput transformer 100watt with a 6.6K input impedance and a 4ohm and 8ohm output
Questions:
1. A KT-120 power tubes uses 1.9amps per tube for fil (2x), 12AX7 is 150ma, 6SN7 is 300ma... so ~ 4.25amps is a 6amp 6.3 winding enough... isnt the general thinking we should double the current needs; meaning 8.5amp 6.3 winding?
2. 2 KT120s are biased at 65-70ma per tube? What would KT150s be biased at. I bias my KT88 at ~55ma per tube. The 70% rule always confuses me.
3. KT150s would yield more power or just last longer?
4. WHy 6.6K and not 5K or 4.3K. I thought larger power tubes perfer lower impedances? Im runing my stock Eiclone with 4.3K primarys and really love the sound.
5. Why no choke?
Thanks,
I used chokes, Higher rated power supply caps 450v ea,, 3 amp diodes in series, cl-80 thermistors for higher current rating, 3 amp fuses, and other changes. My amp works flawlessly and I love it.
Here are the chokes and output trans I used.
Product(s)
#
Name
Price
Quantity
Total
1 CXPP100-MS-4.2K $98.51 2 $197.02
2 XC87-2H-300mA $30.84 2 $61.68
Justin
justinsweber wrote:Thank you for the info... few more questions.
Looking at the parts list.
Power transformer for a 120V, 60Hz. line to 900V (450-0-450) at 300mA and 6.3V at 6A.
Ouput transformer 100watt with a 6.6K input impedance and a 4ohm and 8ohm output
Questions:
1. A KT-120 power tubes uses 1.9amps per tube for fil (2x), 12AX7 is 150ma, 6SN7 is 300ma... so ~ 4.25amps is a 6amp 6.3 winding enough... isnt the general thinking we should double the current needs; meaning 8.5amp 6.3 winding?
2. 2 KT120s are biased at 65-70ma per tube? What would KT150s be biased at. I bias my KT88 at ~55ma per tube. The 70% rule always confuses me.
3. KT150s would yield more power or just last longer?
4. WHy 6.6K and not 5K or 4.3K. I thought larger power tubes perfer lower impedances? Im runing my stock Eiclone with 4.3K primarys and really love the sound.
5. Why no choke?
Thanks,
examine pic closely and you will see the chokes.
download/file.php?id=767
Justin
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