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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: 10 Aug 2010, 11:14 
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homik wrote:
But hey, everything turned out well in the end. no hard feelings. :headphones:

The one and only important thing, you got that critter walking ...and it looks good to :mrgreen:


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PostPosted: 10 Aug 2010, 11:15 
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Joined: 22 Jun 2010, 13:30
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i ment it funny

not to be hurt or hurt anybody (just a funny comment)


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PostPosted: 13 Aug 2010, 17:21 
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Joined: 13 Aug 2010, 17:12
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Hello, I've built my own little amp following the guide but I have a problem: the heaters don't seem to work: no glow, no heat, 12V across pin 4&5, new tube, 12AU7A/ECC82EH electro-harmonix


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PostPosted: 13 Aug 2010, 19:27 
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Joined: 28 May 2008, 21:53
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Location: Winnipeg, CANADA
It could be a defective tube. Can you check the voltage on Pin 9 which is the center tap of the two heaters.

Also, if you pull the tube out of the socket and measure the resistance between pins 4 and 5, what do you get?
Cheers

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[ DIY Mains AC Power Cable Cord ] - [ Gobo LM1875 Amp Kit ] - [ Tang Band D4-1 Horn Speaker Kit ] - [ Monoblock Push-Pull KT88 Tube Amp Kit ]


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PostPosted: 13 Aug 2010, 19:35 
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Problem solved! The pinout was completely wrong^^... first tube amp

My second problem is the bias, since the pots are at their max so I can't get under 6.9V and 8V


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PostPosted: 15 Aug 2010, 11:15 
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Hi Mr2D, did you use a 10k pot? Can you post some photos so we can take a look? You may have a wiring error elsewhere.
Cheers

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[ DIY Mains AC Power Cable Cord ] - [ Gobo LM1875 Amp Kit ] - [ Tang Band D4-1 Horn Speaker Kit ] - [ Monoblock Push-Pull KT88 Tube Amp Kit ]


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PostPosted: 17 Aug 2010, 15:42 
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Hi

I've added a 3 sec. delay relay to the headphone-output, for my Rogers Gomez NP-100v12 Amp, to avoid the turn on thump, when powering it up. This add-on is a simple diy project, which almost everyone, even beginners can make. :up:

I've made a separate thread for the Simple Turn On Delay Circuit (Relay) for Amplifiers and Speakers.

Pictures of the add-on delay relay and my 10 A-h battery powered headphone amp, with 500 mA-h charger:

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PostPosted: 22 Aug 2010, 06:27 
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Joined: 13 Aug 2010, 17:12
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Hello, here are the pics: a very messy work

Image

Image

I'm using 2 10k pots

The amp works despite the wrong voltages, I have one strong channel and a weak one, is this normal?


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PostPosted: 22 Aug 2010, 08:16 
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Hi Mr2D

I've got a question ...are there some differences of the illustrated resistors value ( red vs. blue circle ) and how/to what are they coupled ? What it seems blue ring = 2 pcs of 56 Ohm resistors in serial = 112 Ohm and red ring 1 pcs of 150 Ohm ?
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Mess = yes :mrgreen: ...but the funny thing is, that it is possible to get your build sound as good as one assembled beautiful. :wizard:

But ...how about trying one more time, with a new piece of veroboard ... desolder all components and mount them again, this time more structured, all from the same site of the board and solder it together again on the soldering site. You could imitate the original print, then it would be easier to help you with troubleshooting. ( see it as positive criticism ) :up:
Image


Last edited by KrammeAcoustics on 22 Aug 2010, 09:01, edited 3 times in total.

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PostPosted: 22 Aug 2010, 08:54 
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Joined: 13 Aug 2010, 17:12
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There are no diferences between "red" and "blue", both are 150 ohms coupled with 100uf cap.

I may rebuild this thing but I don't know if the components will survive especially the transistors.

I'm actually using stereo jacks for input / output. How am i supposed to wire them?


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