Photo Gallery

[Wavebourn]

100W per channel from 20 Hz of High-End sound quality. Balanced & unbalanced inputs, 0 dB sensitivity with optical compressor-limiter that engages instead of clipping. Indestructible Gu-50 military output tubes.

 

[Carlp]

100W per channel from 20 Hz of High-End sound quality. Balanced & unbalanced inputs, 0 dB sensitivity with optical compressor-limiter that engages instead of clipping. Indestructible Gu-50 military output tubes.

Wait, so Gu50s are in the black "holders" in back? Are the sockets relatively available for them? And what are the 3 tubes in the driving circuit? Curious for more about this.

Carl

 

[Wavebourn]

Wait, so Gu50s are in the black "holders" in back? Are the sockets relatively available for them? And what are the 3 tubes in the driving circuit? Curious for more about this.

Carl

6F1P, 6P15P.

3 PCS METAL - CERAMIC 8-PIN SOCKET GU-50 / LS50 / 5C9S with GU-50 AS IS tubes | eBay

 

[felixx]

Nice project Wavebourn...can you share the schematic diagram?

 

[Wavebourn]

Nice project Wavebourn...can you share the schematic diagram?

Hhanks!

800V kills!

Here is the driver of one previous version. It does not show nested feedbacks though. I did not draw the last one yet, but it is pretty similar.

 

[Carlp]

6F1P, 6P15P.

3 PCS METAL - CERAMIC 8-PIN SOCKET GU-50 / LS50 / 5C9S with GU-50 AS IS tubes | eBay

Thx!

 

[Wavebourn]

After 6 straight hours of playing music. Temperatures are stationary and I doubt they will go higher.

 

[Wavebourn]

The top of the chassis, above voltage regulators (MOSFETs)

 

[hpeter]

Omg, such a nice parts shop.. glad I read this forum.. how do the toroid OPTs perform from this company ?

i have not measured them, but sound is good. /el84se/

 

[TonyTecson]

6L6GC pp amp now playing music....

 

[Sodacose]

6L6GC pp amp now playing music....

Beautiful. What is the 9 pin tube?

 

[TonyTecson]

Beautiful. What is the 9 pin tube?

5814

 

[Wavebourn]

Flea power amp on the bench. As you may see from the pictures, 4W from 20 Hz, and on -3 dB from 6 Hz to 120 KHz.
Bats and pets should be happy? ;-)
Output tubes 6CD6, driver tube 8CB11
VR150 + IRF740 stabilize screen grid voltages. Semi-automatic bias; 8.6V DC from 8CB11 filament + 100 Ohm resistors.

Who said that Edcor transformers are not wideband, and who said that sweep tubes are not linear?

 

[jdg123]

Wow!

Now that little beauty is going to be of great interest to builders of all stripes! Are you interested in passing on the details?

 

[Carlp]

Flea power amp on the bench. As you may see from the pictures, 4W from 20 Hz, and on -3 dB from 6 Hz to 120 KHz.
Bats and pets should be happy? ;-)
Output tubes 6CD6, driver tube 8CB11
VR150 + IRF740 stabilize screen grid voltages. Semi-automatic bias; 8.6V DC from 8CB11 filament + 100 Ohm resistors.

Who said that Edcor transformers are not wideband, and who said that sweep tubes are not linear?

Nice! I agree about Edcors. They always seem to perform above specs but I've never measured.

 

[Wavebourn]

Now that little beauty is going to be of great interest to builders of all stripes! Are you interested in passing on the details?

12.6V CT filament transformer, 6.3V halves power filaments of 6CD6 tubes. Rectified by Shottky pair results in 8.6V for 8CB11 filament.
Driver: 120 Ohm in cathode, 24K in anode, 145V to screen grid through 1.5k, a cap from it co cathode 0.1 uF.
Cathodes of output tubes sit on 8.6V filament through 100 Ohm resistors; 4,700 uF caps to ground.
Feedback resistors from anodes to anodes, 240K
Industrial anode transformer, 120/240V.

That's it, al secrets revealed. ;-)

 

[Wavebourn]

I forgot about the last touch; 2.41k resistors from secondaries to driver cathodes.

 

[JoeAlders]

I forgot about the last touch; 2.41k resistors from secondaries to driver cathodes.

Is that the cause of the just noticeable ringing on the square
wave ?

 

[vinylkid58]

Flea power amp on the bench. As you may see from the pictures, 4W from 20 Hz, and on -3 dB from 6 Hz to 120 KHz.
Bats and pets should be happy? ;-)
Output tubes 6CD6, driver tube 8CB11
VR150 + IRF740 stabilize screen grid voltages. Semi-automatic bias; 8.6V DC from 8CB11 filament + 100 Ohm resistors.

Who said that Edcor transformers are not wideband, and who said that sweep tubes are not linear?

Nice!

 

[Wavebourn]

Is that the cause of the just noticeable ringing on the square
wave ?

No. It is the cause of inperfectness of any output transformer.
However I can add a capacitor in parallel with feedback resistor that people add for the measurement sake, but that 100+ KHz slight ringing matters less than bandwidth and slewrate. I don't want to add after that a dominant pole compensation that may be needed due to the increased gain over the loop.

Edit: sorry for OT in Photo Gallery; I don't mind if the moderator moves unrelated posts to a separate thread.