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[56oval]

Mal,

Yep that is exactly what those are. I would say to buy a batch of 10, because at first I had some arc-overs during prototyping. It was probably my own mistake though, because I didn't take as good care for their layout as I should have. There is a max heater to cathode rating that I didn't want to exceed, so I tied the heater to the cathode, in effect making it direct-heated. They're reliable in full wave bridge with heater tied to cathode now, and also make sure to insulate the individual socket contacts well with heat shrink. You see that I used four of these diodes - one each of the others are used in the series with the driver's dual-mono supply just for slow startup and dropping a little voltage. The amp sounds phenomenal, and I would definitely use these diodes again!

And one more tip - if you plan to pair this with high eff speakers >95db and are sensitive to any hum/noise, then I would recommend trying DC heating of the diodes.

Cheers mate ,thanks for the info 🙂.

 

[Nikon1975]

Tubelab 45

This is a TubelabSE for 45 and 2A3.

Iron is from Silk and it has the possibility to check and adjust bias without opening the chassis.

D.

 

[Nikon1975]

Tubelab SE 45

Pictures did no go through.

D.

 

[felixx]

Nice.What speakers did you use for them?

 

[Nikon1975]

The idea is to use it with the microFonken, but up to now I only had the possibility to connect it to the Sonus Faber Grand Piano. It sound good, but not loud for sure.

D.

 

[felixx]

Sonus Faber Grand Piano............if you want to drive them very good,you need a "welding machine amp" for those.
In case you don't want biamping for your sistem you should try on your local guys to experiment on Maxonic speakers or similar or...a very good back loaded horn type enclosure (Fertin-fullrange speaker or FS speakers).

 

[AirPower]

My reference Amp, It drive the JBL 4344 very easily. I'm must used 16 caps 560uF/450V in power supply for bass enought strong at full Power output.

Specifications:
- Vacuum Tube Complement:
8 x 3D21WB, 2 x 12SL7 , 2 x 6BX7
- Output Power 90 Wrms (4 Ohms)
10 Hz – 50 kHz ± 3dB (at full power)
- Class of output operation: AB1
- Input Sensitivity / Impedance: 1V / 100K Ohms
- Dimensions W x D x H: 42 x 42 x 21 cm
- Weight per unit: 36 Kg

 

[firechief]

Air Power -- WOW -- very special workmanship. I presume that you designed the board. That alone is a lot of work.

 

[mhouston]

Air Power -- WOW -- very special workmanship. I presume that you designed the board. That alone is a lot of work.

I'm with this guy. Knockout amp. Makes my SETs look like toys.

 

[tubelectron]

Hello All,

Any of you have built OTL tube amplifiers ?

Here are my 2 OTL mono blocks (built in 1993) - I hope that the picture will be displayed correctly below :

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

A+!

 

[mhouston]

Tubelectron: Equisite work.

 

[AirPower]

300B push pull

 

[Wavebourn]

My reference Amp, It drive the JBL 4344 very easily. I'm must used 16 caps 560uF/450V in power supply for bass enought strong at full Power output.

Specifications:
- Vacuum Tube Complement:
8 x 3D21WB, 2 x 12SL7 , 2 x 6BX7
- Output Power 90 Wrms (4 Ohms)
10 Hz – 50 kHz ± 3dB (at full power)
- Class of output operation: AB1
- Input Sensitivity / Impedance: 1V / 100K Ohms
- Dimensions W x D x H: 42 x 42 x 21 cm
- Weight per unit: 36 Kg

Good professional design. I like it.

 

[CLS]

The main planes of the plates of the 2 output tubes are facing each other, so their radiating heat would be baking each other.

However I don't know how much it'd be an issue practically.

 

[djn]

Here is my latest build. Organ chassis with Maggie OPTs and 6LU8 compactron tubes. Should have it done next week. The 6LU8s will be mounted on top of the boobies.

 

[spswmsw]

Parallel 6AG7 SE

Hello all!
Here is my amp. Mixed schematic from several sources.
Output stage with Russian 6P9 (6AG7) two in parallel.
Screen stabs are STR 150/30.
Line stage – Russian 6N8S (6SN7).
Bias rectifier – Russian 6X6S (6H6).
Power rectifier – Russian 5Tz3S (5U4G).

 

[Cassiel]

Wow, rectifier tubes on top of power transformers. Saving space? Talking about space, by any chance do you like rockets?

 

[nicoch58]

😀

 

[spswmsw]

Nice considerations. Charming. Well, the space is great but here it doesn't matter. I've got this unique vintage power trans with such a tube placement, manufactured in 1953 for some kind of a specific device for the Sovier Army. Great core iron.
I like rockets since my next of keen was a pilot of the TU-95 aircraft "Bear".
About trying anything ... any try is a chance for the advance and progress. Thanks for wishing the bless.
Have a nice day!

 

[kavermei]

Wow, rectifier tubes on top of power transformers. Saving space? Talking about space, by any chance do you like rockets?

This arrangement used to be more common than it is today. I guess it makes sense, in many ways.