YAHA

[Plexcio Acoustics 0]

Thanks to neutralzz for the detailed PM he sent me about building this amplifier

 

 

More details on this amp can be found here

 

The original reason for starting the project was for me to build myself something that can last me till 2011 when I finally go for NS. I'm doing this with the mentality of maxing out every possible component in the amplifier except those that are able to be swapped out easily well hoping that I am able to get the best possible sound out of it!

 

I have already bought the resistors, voltage regulator, op-amp and tubes

 

All I am left with are the capacitors and I am still considering what brand and size I should buy(I'm only a student so I'm only limited to the goodies in Singapore). Size is not an issue here. Price wise... Perhaps $200 for C2 and about 50 for C1?

 

The power supply is still a huge question mark in my head now. Should I get a entry level PSU or just use those AC/DC converters that can be found in hardware stores. I will be trying to power it with a lithium polymer 11.1V nominal 2200mAh battery too.

 

So I hope you guys could help me with the capacitors, PSU and the pinouts of the 6922 tube

 

Cheers! *we need a beer mug emoticon*

[neutralzz 0]

Thanks to neutralzz for the detailed PM he sent me about building this amplifier

 

More details on this amp can be found here

 

The original reason for starting the project was for me to build myself something that can last me till 2011 when I finally go for NS. I'm doing this with the mentality of maxing out every possible component in the amplifier except those that are able to be swapped out easily well hoping that I am able to get the best possible sound out of it!

 

I have already bought the resistors, voltage regulator, op-amp and tubes

 

All I am left with are the capacitors and I am still considering what brand and size I should buy(I'm only a student so I'm only limited to the goodies in Singapore). Size is not an issue here. Price wise... Perhaps $200 for C2 and about 50 for C1?

 

The power supply is still a huge question mark in my head now. Should I get a entry level PSU or just use those AC/DC converters that can be found in hardware stores. I will be trying to power it with a lithium polymer 11.1V nominal 2200mAh battery too.

 

So I hope you guys could help me with the capacitors, PSU and the pinouts of the 6922 tube

 

Cheers! *we need a beer mug emoticon*

 

well too bad i dont have an account on the other forum so i cant post there

 

but typically i'm more of a tube purist than a hybrid amp lover, although there are decent sounding hybrids out there

 

the YAHA is a funny amp, i dont know but due to the extremely low plate voltage, you are far from linearity.. but anyway........the pin outs of an ecc88 is similar to that of 6dj8,e88cc, 6922 etc.

 

you can find loads of datasheets here : http://tdsl.duncanamps.com/

 

 

this is the base of the tube with the pins pointing at you, as a twin triode, you have 2 grids, 2 plates (anodes), 2 cathodes (always close to ground, biased with a resistor), 2 pins for filament heating, and 1 pin for shield grounding, i.e. pin 9

 

input signal, will always go to the grid, with each cathode as K in the picture, and each anode as A.

 

the cathode determines the bias of the tube, in this case you are probably not using an automatic bias with a resistor. the anode, must always be connected to a positive charge to draw electrons across. and as for the filament.. just heat it with 6.3v ac or dc will do, with DC being quieter than AC, but AC sounds a little more "lively" at the expense of slight hum.

Edited December 3, 2009 by neutralzz

[Plexcio Acoustics 0]

Ermm... Actually what I don't know is what is what on the schematic

 

Quite new to this so I don't really know much about tubes and I'm not the sort of electronics student either...

 

I'll be using a DC voltage for the heater. Already got the LM317 =)

Edited December 3, 2009 by sphb

[neutralzz 0]

Ermm... Actually what I don't know is what is what on the schematic

 

Quite new to this so I don't really know much about tubes and I'm not the sort of electronics student either...

 

I'll be using a DC voltage for the heater. Already got the LM317 =)

 

 

the dotted line in your schematic in the middle of the circle is the grid, so for left channel you can connect it to G on the 9 pin tube, and for right channel you can connect to G1.

 

for the resistor 47k & the input to opamp, you connect the tube's plate, which is the anode, denoted by A in the 9 pin diagram.

 

for your cathode, you actually connect it to ground, the input to ground is paralleled to the tube via a 1M resistor. so you connect K and K1 of the tube directly to the ground.

 

 

pins 4 and 5 will be your heater pins.

 

the LM317 will run hot in this case, you can bend it and screw it to the chassis to use that as a heatsink or buy a chip heatsink

 

[wwenze 0]

Ok lar, at 0.3A current draw to drop 5.7V will only result in 1.71W, doubt you'll need a big heatsink for the LM317 if you're using TO-220 package, or just screw to case will do.

 

If you got the TO-220 version that is.

Edited December 4, 2009 by wwenze

[Plexcio Acoustics 0]

Wow really detailed

Will it help with the heat if I use 2 LM317s in parallel for each side?

 

Anyway any suggestions on maxing out the caps c1 and c2?

[neutralzz 0]

Wow really detailed

Will it help with the heat if I use 2 LM317s in parallel for each side?

 

Anyway any suggestions on maxing out the caps c1 and c2?

 

i still dont feel a need to max out the caps unless you know the sound of what you're going to make.

 

start with a cheap cap, and if the setup sounds good, put in better caps.

 

the prices of a pair of good capacitors can buy you a commercial amplifier already..