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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: 28 Mar 2020, 10:58 
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Joined: 21 Mar 2020, 05:26
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Hi Bruce I'm having a go at the amp you designed,I was wondering if I could use two 317s in parallel to dissipate a little more heat ,would the resistor values change.Many thanks Darryl


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PostPosted: 22 Apr 2020, 05:36 
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Joined: 03 Apr 2016, 00:33
Posts: 17
Location: Amsterdam, Netherlands
Bruce, little question : is there any objection to placing the BIAS measuring points and trimpot at the rear of the chassis ? (Longer leads to the valves)


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PostPosted: 22 Apr 2020, 21:01 
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Joined: 04 Jun 2008, 20:59
Posts: 4192
Location: Arizona, USA
Hi, No. We do it in the commercial version. It works fine there.

Good listening
Bruce

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PostPosted: 14 May 2020, 16:13 
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Joined: 25 Feb 2012, 09:33
Posts: 8
Location: Wakefield, West Riding of Yorkshire
Hi Bruce, built this great amp a couple of years ago, sounds fantastic, really pleased with it's performance. I'm thinking of connecting a sub woofer to the added circuit mod. Does it have to be an active sub? Can I use a 3 or 4 watt passive? The output connection between the VD is obvious, does the other connection go to the speaker output ground?


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PostPosted: 14 May 2020, 21:18 
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Location: Arizona, USA
Hi, I 'm glad you like it. The sub will have to be self powered...or alternatively have its own amp. Depending on how loud you listen, you might be able to get by with a passive crossover on the existing outputs. It would depend on the sensitivity of both the main and sub speakers.

Good listening
Bruce

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PostPosted: 18 May 2020, 15:23 
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Joined: 25 Feb 2012, 09:33
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Location: Wakefield, West Riding of Yorkshire
Sorry, I don't think I'm doing a very good job of explaining myself!
I assume there is a sub output from both channels, could you explain in the simplest of terms, or even better provide a drawing or diagram to show exactly how I connect these two outputs to a powered mono sub.


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PostPosted: 18 May 2020, 15:56 
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Location: Arizona, USA
Hi, There are two possible ways to do this. Most powered subs have line inputs. One for the left and one for the right. You need to connect a RCA cable from each of the sub outputs on the Poddwatt to each of the line inputs on the sub. It will mix them together for you. If in the event there is not enough gain that way you can use the speaker inputs on the sub and run wires from the speaker terminals on the amp to the speaker inputs on the sub. Again it ought to handle the mix for you.

Good listening
Bruce

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PostPosted: 19 May 2020, 05:42 
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Joined: 25 Feb 2012, 09:33
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Location: Wakefield, West Riding of Yorkshire
Thanks Bruce
At which point do I take the sub outputs negative/earth?
Apologies for the dumbness of my questions, I can solder and follow a circuit diagram but I still have a lot to learn!
Cheers
Steve


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PostPosted: 19 May 2020, 10:06 
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Location: Arizona, USA
Hi, If the sub uses RCA connectors for line input and the Poddwatt has the sub out jacks (not all the designs did) then they will automatically connect. If you use the speaker configuration then you need to run both the hot and ground wires from each speaker output terminal on the amp to the respective input connectors on the sub. Most have pairs of input connectors often with push terminals.

BTW. Asking "dumb" questions is a survival skill in diy audio...especially with tube gear. It can save your life.

Good listening
Bruce

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PostPosted: 20 May 2020, 21:37 
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Joined: 14 Sep 2015, 09:36
Posts: 5
Hi Bruce,
I have read all the posts on this thread and is contemplating to build the later version of the Poddwatts amplifier. I would like to get the transformer package from Edcor. However, I have concern about the power transformer. The primary winding are for 240V or 120V. I live in an area where the line voltage is 220V. If I order the 240V version, the secondary will be around 165V, and after rectifier, it would be around 230V. Would that be too low for the optimal functioning of the amp, or could be fixed by using lower resistor values the filtering network, or may be using a choke? Your advice would be appreciated.


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