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 NEW  Matt presents bias and operation data for the 6V6 tube in SE operation - 6V6 Single-Ended (SE) Ultra Linear (UL) Bias Optimization.

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PostPosted: 13 Jan 2010, 17:24 
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Joined: 15 Dec 2009, 17:28
Posts: 70
Location: Netherlands
Bennybuis wrote:
That is also a killer headphone amp, really. That little thing really rocks. Idid all the little improvements, like grounding the filament circuitry with 0,01 uF respectively to ground, that made it even more quiet.

Could you show and tell what exactly you modified in the JAN6418 thread? Thanks.


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PostPosted: 13 Jan 2010, 17:28 
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Joined: 24 Feb 2009, 03:24
Posts: 562
Location: USA
HI!
Where I can buy 12B4A? I lake it's Ri - 1 kohm!

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Hi End is back proportional to the number of composite parts!
Projects: OTL 6AS7 Gen, Electric, SEs 2A3 RCA, 300B JJ, 6S4S, 4P1L, EL11 Telefunken, 6AS7 RCA, 6S33S, 6S41S, 6S19P, PP 6005 Gen. Ellectric , headphone ampl. OTL Loftin White 6AS7 RCA....SE E84L& E80CC Siemens&Tel-n.
http://azazello-sound.blogspot.com/


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PostPosted: 14 Jan 2010, 03:12 
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Joined: 02 Mar 2009, 12:41
Posts: 1110
Location: Vänersborg, Sweden
azazello wrote:
Where I can buy 12B4A? I lake it's Ri - 1 kohm!

I can send you a pair. Guess I still have some left. I also have some CDs for you but I have mislaid them ... :confused:

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Magnus

“If you don't know where you are going, any road will get you there.”
―Lewis Carroll


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PostPosted: 14 Jan 2010, 03:51 
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Joined: 28 Oct 2009, 02:34
Posts: 501
Location: Utrecht Nederland
Hallo everybody,

well here is the final schematic, just like I build my amp. Any suggestions are as usually more than welcome, since I don't really know what I am doing, I kind of get liucky :smoking:


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Greetings from Holland, Ben

My DIY Audio Projects:
- Single-Ended 12B4A tube amp with ECC802S driver
- DIY Push-Pull KT88 tube amp (OddWatt amp from scratch)
- 832 / GU32 tube push-pull amplifier project


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PostPosted: 14 Jan 2010, 04:08 
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Joined: 28 Oct 2009, 02:34
Posts: 501
Location: Utrecht Nederland
Note, tat the 8,2 uF poly cap located on the amp schematic is located right where the two output transformers are connected together for B+ and this cap is common for both channels. Should be really 10 uF, if you can get them, I can not, or almost not, got only one and wanna keep it for a "serious amp".]
Anyway, I closed the lid on that little amplifier and I am so ready to start something mew, I am already sanding the bigger cigar box.......

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Greetings from Holland, Ben

My DIY Audio Projects:
- Single-Ended 12B4A tube amp with ECC802S driver
- DIY Push-Pull KT88 tube amp (OddWatt amp from scratch)
- 832 / GU32 tube push-pull amplifier project


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PostPosted: 14 Jan 2010, 07:10 
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Joined: 24 Feb 2009, 03:24
Posts: 562
Location: USA
BEN!
Connect el. cap 100 uf from cathode preampl. direct to ground, not between meddle point of resistors!
It will be better to sounding!

Magnus!
Thanks!

_________________
Hi End is back proportional to the number of composite parts!
Projects: OTL 6AS7 Gen, Electric, SEs 2A3 RCA, 300B JJ, 6S4S, 4P1L, EL11 Telefunken, 6AS7 RCA, 6S33S, 6S41S, 6S19P, PP 6005 Gen. Ellectric , headphone ampl. OTL Loftin White 6AS7 RCA....SE E84L& E80CC Siemens&Tel-n.
http://azazello-sound.blogspot.com/


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PostPosted: 14 Jan 2010, 12:02 
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Joined: 28 Oct 2009, 02:34
Posts: 501
Location: Utrecht Nederland
Hallo everybody,

Nikola, you are right about the 150 ohm resistor, it is only there, because I wanted to feed it NFB to this point, but since there is no feedback, I can take the resistor out and replace the 330 ohm with 470 ohm, it will sound even a bit better. But I am not sure yet, if the amplifier really doesn't need any feedback, with my ears I cannot determine that, I tried, the differences to hear are to small to adjust the feedback loop by ear, you can surely do that with the proper amount of experience, but this I lack as well.

_________________
Greetings from Holland, Ben

My DIY Audio Projects:
- Single-Ended 12B4A tube amp with ECC802S driver
- DIY Push-Pull KT88 tube amp (OddWatt amp from scratch)
- 832 / GU32 tube push-pull amplifier project


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PostPosted: 14 Jan 2010, 13:18 
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Joined: 24 Feb 2009, 03:24
Posts: 562
Location: USA
BEN!
How is anode current of output tube and pre tube? You can measure U every cathode ...I=U/R.

_________________
Hi End is back proportional to the number of composite parts!
Projects: OTL 6AS7 Gen, Electric, SEs 2A3 RCA, 300B JJ, 6S4S, 4P1L, EL11 Telefunken, 6AS7 RCA, 6S33S, 6S41S, 6S19P, PP 6005 Gen. Ellectric , headphone ampl. OTL Loftin White 6AS7 RCA....SE E84L& E80CC Siemens&Tel-n.
http://azazello-sound.blogspot.com/


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PostPosted: 16 Jan 2010, 00:09 
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Joined: 28 Oct 2009, 02:34
Posts: 501
Location: Utrecht Nederland
Hallo Azazello,

I have across the cathode resistor 21 volt, does that help? Otherwise I have to unsolder and measure with the multimeter.

_________________
Greetings from Holland, Ben

My DIY Audio Projects:
- Single-Ended 12B4A tube amp with ECC802S driver
- DIY Push-Pull KT88 tube amp (OddWatt amp from scratch)
- 832 / GU32 tube push-pull amplifier project


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PostPosted: 16 Jan 2010, 03:48 
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Joined: 24 Feb 2009, 03:24
Posts: 562
Location: USA
Ben!
You have 26 ma for output tube. It's small for good sound. Put in cathode 620 ohm/3-5 watts
to increase current to 35 ma.Try to change ECC83 to 12AT7 and resistors 470 ohm to 220
and compare the sounds....

_________________
Hi End is back proportional to the number of composite parts!
Projects: OTL 6AS7 Gen, Electric, SEs 2A3 RCA, 300B JJ, 6S4S, 4P1L, EL11 Telefunken, 6AS7 RCA, 6S33S, 6S41S, 6S19P, PP 6005 Gen. Ellectric , headphone ampl. OTL Loftin White 6AS7 RCA....SE E84L& E80CC Siemens&Tel-n.
http://azazello-sound.blogspot.com/


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