Single ended 6L6 output transformer

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Wilson
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Single ended 6L6 output transformer

Post by Wilson »

Hi, I just salvaged a single ended 6L6 amp from a 1960 reel to reel. The OT is a Schumacher but it has three wires on the secondary side yellow, green, black. The black wire was going to cathode of the 6L6. I've never seen three wires on the secondary side of a single ended OT - anyone know what that's about?

Thought I'd build a 6L6 Champ.
brewdude
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Re: Single ended 6L6 output transformer

Post by brewdude »

Do you mean the primary side?
Could it be an ultra linear tap?
Wilson
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Re: Single ended 6L6 output transformer

Post by Wilson »

Secondary. Color scheme is fairly normal, blue / brown on the primary and green / black/ yellow on the secondary.

Is there ever any reason to use a center tap on a secondary?
Stevem
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Re: Single ended 6L6 output transformer

Post by Stevem »

Yup, you can drive the OT like a cathode follower.
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matt h
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Re: Single ended 6L6 output transformer

Post by matt h »

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Last edited by matt h on Fri Mar 27, 2015 3:30 am, edited 1 time in total.
Jana
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Re: Single ended 6L6 output transformer

Post by Jana »

Yes, without a schematic, it's hard to day what it going on. But, it sounds like the secondary is not "centered tapped" but has a common, 4 ohm, 8 ohm taps. You could verify that by measuring the turns ratio.
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Wilson
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Re: Single ended 6L6 output transformer

Post by Wilson »

matt h wrote: you can ground the cathode THROUGH the secondary of the OT as a means of providing some local NFB as well.

Without having a full description of the circuit (or schematic) it's hard to say exactly what's going on.
This may be it because the OT seems to be the only way that the cathode was grounded.

Measuring the secondaries I get about 1 ohm yellow to green, 16 ohms yellow to black and 17 ohms green to black.

Primary side is about 285 ohms.

The circuit was a real mess as it was integrated into the reel to reel. I just saw "single ended 6L6" and started to grab the parts that I wanted and then realized the 3 wire secondary thing.

Looks like I can just ignore the black wire and use this as a regular SE OT.
Jana
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Re: Single ended 6L6 output transformer

Post by Jana »

:roll:

Number three.

Sorry Steveneddy, you already had your turn in the chair.
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ToneMerc
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Re: Single ended 6L6 output transformer

Post by ToneMerc »

Jana wrote::roll:

Number three.

Sorry Steveneddy, you already had your turn in the chair.
Is that Madam, Ma'am or Mistress :wink:

TM
Jana
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Re: Single ended 6L6 output transformer

Post by Jana »

Depends on the weather. :twisted:
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