Classic 30 OHM?
- Thread starter Pecan
- Start date
Pierre
Stratologist
Re: Classic 30 OHM?
Ohm is the impedance.
Your signal at the exit of the powerstage is not made to drive a speaker. So it goes to the output transformer to become 2, 4, 8 or 16 ohms. You need a matching cab for whichever output transformer and impedance you have. With a tube amp you can mismatch because the transformers are usually very sturdy but it IS NOT ADVISED.
Ohm is the impedance.
Your signal at the exit of the powerstage is not made to drive a speaker. So it goes to the output transformer to become 2, 4, 8 or 16 ohms. You need a matching cab for whichever output transformer and impedance you have. With a tube amp you can mismatch because the transformers are usually very sturdy but it IS NOT ADVISED.
toneseeker
New member
Re: Classic 30 OHM?
Are you talking about a Peavey Classic 30?
If so, the external speaker jack is wired for an 8 ohm cab, instead of the 16 ohms that the speaker is.
Steve Ahola (who has done a lot of mods to his classic 30) recommends taking a speaker jack plug (by itself, it doesn't have a cord attached) and plugging it in. When you plug it in, it switches the amp over to 8 ohms, and is supposed to get a little better sound.
Are you talking about a Peavey Classic 30?
If so, the external speaker jack is wired for an 8 ohm cab, instead of the 16 ohms that the speaker is.
Steve Ahola (who has done a lot of mods to his classic 30) recommends taking a speaker jack plug (by itself, it doesn't have a cord attached) and plugging it in. When you plug it in, it switches the amp over to 8 ohms, and is supposed to get a little better sound.
Re: Classic 30 OHM?
Say what.... never heard of a Classic 30 extention jack being rated at 8ohms.... Everything Peavey seems to make speaker cab wise is 16 ohms.... My mid 90's Classic 30 1x12 sealed back Extention cab is 16ohms... Why would the C30 amp's extention speaker jack be 8ohms?
toneseeker said:
Say what.... never heard of a Classic 30 extention jack being rated at 8ohms.... Everything Peavey seems to make speaker cab wise is 16 ohms.... My mid 90's Classic 30 1x12 sealed back Extention cab is 16ohms... Why would the C30 amp's extention speaker jack be 8ohms?
Re: Classic 30 OHM?
I got 2 long extremely detailed emails back from Peavey today and i'm still trying to get all of it straight... it is detailed and above my level of amp electronics, which is almost nil... i wrote back for some details i'm unclear on.... This stuff has me very interested
But basicly the extention speaker jack was designed for 16 ohm loads/cabs... When you plug a 16 ohm cab into the extention jack the output transformer switches to 8ohm as there is 2 16 ohm speaker loads.... plugging an 8ohm speaker cab in the extention jack will cut power and the total ohms drops to 5.3.. Plus doing so changes the sound of the amp, less low end...
Now the part about plugging a blank jack into the extention speaker jack i'm still foggy on... it is said to drop the volume of the amp but is easier to overdrive and changes the sound of the amp... Plus parts like Tubes and Transformers will get much hotter and have less life... .. i don't quite understand how safe doing this is but i have wrote back to the tech at Peavey for a little clearer details...
Pecan said:
I got 2 long extremely detailed emails back from Peavey today and i'm still trying to get all of it straight... it is detailed and above my level of amp electronics, which is almost nil... i wrote back for some details i'm unclear on.... This stuff has me very interested
But basicly the extention speaker jack was designed for 16 ohm loads/cabs... When you plug a 16 ohm cab into the extention jack the output transformer switches to 8ohm as there is 2 16 ohm speaker loads.... plugging an 8ohm speaker cab in the extention jack will cut power and the total ohms drops to 5.3.. Plus doing so changes the sound of the amp, less low end...
Now the part about plugging a blank jack into the extention speaker jack i'm still foggy on... it is said to drop the volume of the amp but is easier to overdrive and changes the sound of the amp... Plus parts like Tubes and Transformers will get much hotter and have less life... .. i don't quite understand how safe doing this is but i have wrote back to the tech at Peavey for a little clearer details...
toneseeker
New member
Re: Classic 30 OHM?
Here it is straight from Steve's pdf off of his site. www.blueguitar.org
I may have gotten it a little mixed up.
There is a simple trick to switch the built-in speaker from the 16 ohm tap to the 8 ohm tap: plug a bare 1/4" plug into the Extension Speaker jack. The internal switching contacts of the jack will connect the built-in speaker in parallel to the 8 ohm tap when anything is plugged into the Extension Speaker jack. If you can't afford to replace the stock speaker at this time, be sure to switch it over to the 8 ohm tap.
Here it is straight from Steve's pdf off of his site. www.blueguitar.org
I may have gotten it a little mixed up.
There is a simple trick to switch the built-in speaker from the 16 ohm tap to the 8 ohm tap: plug a bare 1/4" plug into the Extension Speaker jack. The internal switching contacts of the jack will connect the built-in speaker in parallel to the 8 ohm tap when anything is plugged into the Extension Speaker jack. If you can't afford to replace the stock speaker at this time, be sure to switch it over to the 8 ohm tap.
Buckeyedog
New member
Re: Classic 30 OHM?
You can run an 8 ohm cab for a total of 5.3 ohm load, just don't run it real loud for a long period of time. Best to stick with a 16 ohm extension cab though. I had an 8 ohm speaker in my C30 for a while and I ran that dummy jack thing as well. Worked fine. I think I'll try it again with my 16 ohm speaker just to see the difference!
You can run an 8 ohm cab for a total of 5.3 ohm load, just don't run it real loud for a long period of time. Best to stick with a 16 ohm extension cab though. I had an 8 ohm speaker in my C30 for a while and I ran that dummy jack thing as well. Worked fine. I think I'll try it again with my 16 ohm speaker just to see the difference!
