Trafo for 4x6V6

[grtamp]

Hi ,Can I use a Bassman PT and OT for 4x6V6 tubes?

Thanks

[ToneMerc]

Hi ,Can I use a Bassman PT and OT for 4x6V6 tubes?

Thanks

yes

TM

[grtamp]

Thanks TM

Bye

[bal704]

If you use the tubes in parallel (2 parallel sets of 2), does that change how the impedance gets matched on the OT? For example, would you have to use the 16 ohm tap for an 8 ohm load?

[grtamp]

I think 4 ohm tap with 4ohm speakers!!

[cbass]

6V6's Load is about double that of a 6L6.So 4 6v6's work out about perfect for an OT designed for two 6l6's.

[grtamp]

I will use 4ohm tap with a 8 ohm cab speakers?

[cbass]

I will use 4ohm tap with a 8 ohm cab speakers?

No you were correct when you said four ohm tap with a four ohm speaker.

I was responding to bal704's question.

Sorry bout the confusion.

[bal704]

Thanks for the replies. I wasn't sure if having 4 tubes, rather than 2, would change the impedance the OT was seeing.

[tubeswell]

A tweed bassman OT is 4k2 Pr Z into a 2R secondary.

A nominal Pr Z for 4 x 6V6 in PP (i.e. 2 x 6V6 in parallel on each side of the Ot primary) is 3k3 to 5k (depending on a range of other factors such as plate voltage and plate current etc), so the 5F6A-spec OT will work provided you run a 2R secondary load - and you could in fact run the secondary load at slightly less than 2R or slightly more than 2R.

If you were going to run just 2 x 6V6 inPP, then double the secondary load to 4R (to get an 8k PrZ)

[rdjones]

Thanks for the replies. I wasn't sure if having 4 tubes, rather than 2, would change the impedance the OT was seeing.

The impedance that the transformer sees is the load, which is "transformed" or reflected back to the tubes.
The tubes then see the load presented by the transformer based on its turns ratio.

There may be a limited range of useful values with an original Bassman transformer since these don't have taps, just a single secondary winding.
2 ohms for a Tweed, 4 Ohms for the Blackface and Silverface.

rd

[grtamp]

Thanks cbass!!

[rdjones]

For practical load impedance purposes 4x6V6 = 2x6L6.
Keep in mind that the Bassman power transformer may be providing a higher plate voltage than what 6V6s may be comfortable at.
It can be dealt with by lowering the screen voltage.

rd