2k5 Load

[Mats]

When I tried my small 6V6 SE amp.
I hooked up the 4 Ohm speaker to
the Hammond 125CSE.
No problem it worked OK Plate 259 V, Screen 243 V
and Cathode 11 V (Icathode about 50mA).
Then after a while I noticed that my 4 Ohm speaker
was connected to the YEL-wire (OT) and then the reflected
Imp. is 2k5 Ohm, was intended to be 5k.
It sounded OK.
Any harm done, in this hook up ?
OK to hook up this way ?
Later I had a look at the data for 6V6 and there I read for 2k5 load, a little less
output, little higher Iplate and less Iscreen, more 3rd Harmonics dist.
Mats

[tubeswell]

It usually doesn't harm a tube amp to run it 'a knotch' above or below the optimum load resistance, and if the amp still works okay, there's no harm done (even tho' its not an optimal situation). If you've run it that way for a while, there may be a bit more wear on the output tubes,. Change it back to 5k and see how it runs.

[PRR]

A cathode-bias single end amp can be run at any lower impedance without harm. Just less output.

Doesn't even hurt the tube. Worst-case is actually silent idle. With optimum load and FULL output. the tube runs cooler. With off-optimum load and Full output, the tube still runs a bit cooler than at idle.

The only major No-No is running with a MUCH higher than optimum load with FULL signal: while clipping the OT will "spike" and this can puncture the OT insulation.

[Mats]

Thanks for reply !
The sheet, Tung-Sol, says 250V on both Plate and Screen and Ec1 -12V,
Im close to that. Have to keep in mind the 12W Max Disp.
They show load from 2k to 12k and 5k as rated load
I usually go with 5k load, but this time I will try 2k5.
Once again thanks !

[HotBluePlates]

Thanks for reply !
The sheet, Tung-Sol, says 250V on both Plate and Screen and Ec1 -12V,
Im close to that. Have to keep in mind the 12W Max Disp.
They show load from 2k to 12k and 5k as rated load
I usually go with 5k load, but this time I will try 2k5.
Once again thanks !

Then you will see (as shown in page 6 of this 6V6GT data sheet) that for the lower load you will get less than maximum clean output power, and distortion will rise over that if you had used a 6kΩ load. For what it's worth, at the lower load impedance distortion is primarily even harmonic.