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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: 05 Nov 2010, 23:15 
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Joined: 03 Jan 2009, 10:44
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Hi, Gio,
I have the same kit from Uriah. I intended to install it in an extruded aluminum box but it was too small and light, much like the build you described in the forum. I went with a Hammond steel chassis (black) that's about 8" by 4" by 1.5". The size is roomy enough for my remote circuits and it weighs enough to sit still on the shelf. To be honest, thougn, I look at the original aluminum box now and then and think, "what if...?" Like others, I guess, small appeals. Don't know why; it's a lot more work, but it appeals.

The bits arrived for the remote transmitter and receiver. I'll need to set up my microscope to take some pics, and will post more information tomorrow if time permits. Looks like a trip to Radio Shack will be happening soon.

G'night, all.
Lofton


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PostPosted: 06 Nov 2010, 10:17 
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Joined: 06 Jun 2008, 20:12
Posts: 972
Location: Houston, TX
Dont forget that you can place the power supply ANYWHERE, then run wires for power from that to the pot and the pot to the board. That board can be directly on your amps inputs. If you have monoblocks you could use two boards. Trust me, removing an entire RCA cable and its contacts from the system is another increase in sound quality.
Also, I would not do this with a tube amp (high heat) unless I mounted the board directly OUTSIDE the chassis on the inputs.
Uriah

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PostPosted: 09 Nov 2010, 18:49 
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Joined: 28 May 2008, 21:53
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Location: Winnipeg, CANADA
connemaraguitars wrote:
I intended to install it in an extruded aluminum box but it was too small and light, much like the build you described in the forum.

The enclosure I used in my DIY Lightspeed passive attenuator build was a light aluminum box from Radio Shack. If I had rotated it 90 degrees I don't think it would have been an issue. The extruded chassis I have pick out is heavier and by choosing the proper orientation and a heavier knob I don't anticipate any problems.
RiGuy wrote:
Also, I would not do this with a tube amp (high heat) unless I mounted the board directly OUTSIDE the chassis on the inputs.

Wow - good reminder, I had forgotten how sensitive the LDRs are to temperature fluctuations.
Cheers

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PostPosted: 10 Nov 2010, 10:28 
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Joined: 05 Jun 2009, 20:58
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hi, i have another question, if you build a mono attenuator, do you need the optocoupler to be matched? If i understand correctly, you don't need them to be match since you will adjust the second optocoupler with a multipot, am i right? thank you


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PostPosted: 10 Nov 2010, 10:34 
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You are right. There is a small advantage and that is that the total resistance of Resistor A plus Resistor B will stay closer to one value than if they are not matched. A more stable impedance. If you have a very low output impedance source you wont really care much.
Uriah

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PostPosted: 10 Nov 2010, 11:51 
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Joined: 05 Jun 2009, 20:58
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okay, thank you very much.


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PostPosted: 30 Dec 2010, 17:04 
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hey, i have a problem with my attenuator. I think it is from the attenuator i must say... It is a high frequency sound that is not very loud but audible, that sound is off with volume turned down to minimum, go very high pitched at the begining and get down(but still in high frequency range like 10 000hz) when i turn the volume until a bit passed the midle than nothing.
Do you have clue? In that box, there is two 120 watt chipamp, 2 cross over and the lightspeed attenuator.
The problem doesn't go away when the two amp are not powered(these are for the two sub only, the main speaker have their own amp inside). There is no noise if the power is not in the crossover/volume. I would doubt that this come from the crossover since the pitch of the sound change with the volume.
Any help would be very appreciated.
Thank you

Frank


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PostPosted: 30 Dec 2010, 21:06 
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Joined: 05 Jun 2009, 20:58
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never mind, some signal wire was passing too closed from the power supplie :P


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PostPosted: 30 Dec 2010, 22:14 
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Location: Houston, TX
Glad you got it sorted out Frank.
Uriah

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