Ohm, Sweet Ohm

[MusashiChan]

Never, never, never use an tube amp with no cab plugged in it...
It's written on every amp...
It will support a mistake on the other way eg a 8 cab in a 4 plugin socket, but not the opposite.
The output transformer could blow, and on "normal" quality amps like yours, can make a lot of damages on other composants...

[star*CKS]

Hi to all and thanks to Bosco for kicking of the Ohmz thread .Glad to hear your Ht-5 is ok..

I've had my series 1 200 for a few months now but Ive recently been wondering - the speaker outputs are parallel on the series one 200.
Sooo... Would it be better to run a cab ( 8 ohmz speakers ) in mono @ 16 ohms - series
... or Mono 4 ohms parallel.

Would running @ the lower impedance shorten the valves lifespan ?

[Icarus]

Hi to all and thanks to Bosco for kicking of the Ohmz thread .Glad to hear your Ht-5 is ok..

I've had my series 1 200 for a few months now but Ive recently been wondering - the speaker outputs are parallel on the series one 200.
Sooo... Would it be better to run a cab ( 8 ohmz speakers ) in mono @ 16 ohms - series
... or Mono 4 ohms parallel.

Would running @ the lower impedance shorten the valves lifespan ?

Some manufacturers, like mesa for example, allow ohm "safe mis-matching" from say, an 8ohm out into a 16ohm cab.
They encourage users to try it as it changes the characteristics a bit, makes the amp sound a little darker and more compressed.
Some manufacturers discourage it and say only match ohms.
I also have an S1-200 and im sure it recommends matching ohm impedance.

[star*CKS]

Thanks Icarus

It's good to get the info. I've got the ohms matched head to cab. Currently set to 16ohms on the head and into 16ohm mono input on the cab. I'll try using 4 ohms since the both support it. It's only the one cab so 4 ohms should be ok according to the manual - I'm just curious as to how it will efftect the tone .

If you don't mind me asking what do you run yours at ?

[Icarus]

For gigs at small to medium sized venues i use one 16ohm Krank 4x12 cab and have the head set at 16, for larger shows i use 2x 16ohm Krank 4x12 cabs and set the head to 8ohms.

[star*CKS]

Thanks for sharing Icarus .
So your set to 16 also

It's a Randall cab I'm running into at present. I'll have to try a stereo config myself @ some point to.

[Bosco]

Well, my 2x12 cab arrived today so all that remains is to hook it up correctly.

The cab is 16 ohm Stereo / 8 ohm Mono and has two sockets plus a selector switch.

My understanding is this;

Stereo: Effectively two independent 1x12, 16 ohm, cabs.
Options: Single cable from HT5 1x16 ohm out (right socket) to either socket on cab. Useful if I want to keep the noise down a little?
Dual cables from HT5 (middle+left socket) to both sockets on cab.

Mono: Running both speakers in parallel at 8 ohms.
Options: Single cable from HT5 1x8 ohms out (left socket) to 8 ohm mono socket on cab.

Does this sound right?

Also should I be running in Mono most of the time unless I have a special requirement?

I'm 99% sure I know what I'm doing, but after testing my head through headphones and no speakers I thought I'd better get a second opinion this time before I screw-up again.

Thanks.