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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: 01 May 2009, 13:22 
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Location: Vänersborg, Sweden
Cool really.
Got myself a pair of those OP tubes (together with the 5998) for some future projects.

What about the OP tranny? Ra?

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PostPosted: 01 May 2009, 19:26 
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Joined: 03 Aug 2008, 20:22
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Location: Denver, Colorado
I used a cheap Speco T-7010 with variable taps 8k to 500 ohms, I am using the 4k ohm primary tap and 8 ohm secondary. I used them for size although I would think Hammond or Edcor would yield a nicer sound.


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PostPosted: 02 May 2009, 01:06 
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U have sort of promised myself (and my wife) not to invest more in my hobby, but it would be a good idea to bring home a few Edcors from the States this summer ...

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PostPosted: 02 May 2009, 02:01 
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I know what you are saying, I have already purchased another 260v power transformer on ebay, we will have to see what i come up with. so much for saving money.


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PostPosted: 02 May 2009, 02:17 
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And I ended up paying some mediocre $8 for a PSU chassis with a transformer good for a 5W SE-amp ... :lightbuilb:

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PostPosted: 15 May 2010, 08:21 
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Joined: 15 May 2010, 08:09
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Location: Madrid, Spain
Hi friends,

This is my first message, hello all!

I've just bought a pair of Speco t-7010 transformers, to use in a single-ended stereo amplifier. As many people I was unable to find any information or PDF, so I made a measurement.

Image shows frequency response of transformer loaded with 8Ω on secondary. Of course, when you swap the resistor with a speaker, response will change due to speaker frequency-variable impedance. Anyway, you know how to recalculate knowing original transformer response.
Attachment:
Speco-T-7010-Transformer-Frequency-Response.jpg

If you find any mistake, let me know.

Hope it will be useful!
Greetings.


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PostPosted: 15 May 2010, 16:12 
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Hi Simon, welcome to the forum.
Your timing is great as we were recently talking about the Speco T-7010 transformer in this thread: viewtopic.php?f=9&t=1911

Thanks for sharing the measurements.
Cheers

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PostPosted: 18 May 2010, 15:48 
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Joined: 15 May 2010, 08:09
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Location: Madrid, Spain
You're welcome! It's always a pleasure to measure audio parts :)

When I have a chance, I'm going to setup a simple el84 SE amp to achive more "real" measures.
Has anyone tried white noise on a Speco (in a complete amp)?

Regards.


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PostPosted: 21 May 2010, 04:34 
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Updated graphic:

Attachment:
respuesta_freq_specot7010_2.jpg


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PostPosted: 07 Dec 2013, 20:38 
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Joined: 03 Aug 2008, 20:22
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Location: Denver, Colorado
I pulled this amp out of my basement and wanted to play with it again. I did have a little issue with crosstalk. So I decided to remove the LED bias from the pentodes and went with discrete resistor with a bypass cap. Changed to 47 Ohm resistor and 220uF bypass. Sounds much better and a little higher ceiling. Not as loud as some inexpensive class D amps, but fun and warm.
Attachment:
IMG_0788.JPG


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