Making A Mini-Beast Out Of An Old Peavey TKO

[musicallymrm]

:)I was given an old 80's Peavey TKO 80. It's a little 65 watt bass amp with a 12 inch Peavey P.A. speaker in it. I use it a lot lately with my home recording rig. It makes a great sounding preamp/DI for my board and it's the right size for practice or small venue performance. The problem is that the factory speaker sucks royally-breaks up with any reasonable power applied to it so I want to change the speaker.

I've got a friend of mine who had a 12' inch Peavey Scorpion speaker that will drop right in but it's 4 ohm. One of the tech guys at Peavey say that it wasn't recommended to run a 4 ohm speaker in that amp because the amp requires a minimum 8 ohm load. But you know me; amps free, speaker was virtually free so I put it in and man this amp sounds like something way bigger and more powerful than the 65 watt rating. That Scorpion really moves some air and sounds great.

The problem is that my mind keeps going back to the technician's comment that "this amp requires an 8 ohm load" and I don't want to blow the head up. (I love collecting old gear) I haven't used it at any extreme levels yet. Do you guys think that using that speaker will really cause any long term damage? And why couldn't I just go down to Radio Shack and buy a 4-5 ohm resistor and run it in series with the speaker to raise the resistance to 8 ohms that way? Just trying to keep this 29 year old little gem alive and well yet keeping the killer sound I'm getting from it now. Can anyone here help or advise?

[D2o]

Hey, Archie - good to hear from you again

I think you can safely use the 4 ohm speaker for a long time so long as you continue to keep the volume at a reasonable level (i.e. don't try to cause members of your household to spontaneously explode and I would think you should be fine).

But if you really want to start cranking and driving this thing, you'd probably better heed Peavey's advice.

D2o

[ChrisK]

The new speaker may seem louder since you're putting more power through it at a lower volume control level than with the old one.

It may also have a higher Spl rating (be more efficient).

It will work up to a certain level and then you'll start creating overheating in the output stage.

If you want to do the 4 Ohm trick, you can, but Radio Shack may not carry 4 Ohm 50 Watt power resistors.

[musicallymrm]

Jun 17, 2009 15:10:03 GMT -5 D2o said:

Hey, Archie - good to hear from you again

I think you can safely use the 4 ohm speaker for a long time so long as you continue to keep the volume at a reasonable level (i.e. don't try to cause members of your household to spontaneously explode and I would think you should be fine).

But if you really want to start cranking and driving this thing, you'd probably better heed Peavey's advice.

D2o

Good to be back. Every now and then, I do the Marcus Miller thing but most of the time, my music is much more tame. I have an SWR rig that I use when I play out. This little amp is being mainly used in my home studio and small venues. Won't be cranking it too much. My gut was telling me that if I didn't really push this amp too hard, the 4 ohm speaker probably won't be a problem. Played the thing last night at an impromptu jam for about 2 hours. The amp case never even got warm. I remember running Pioneer Receivers wide open back in the day when I used to DJ using cabs made with 4 ohm Pyramid speakers in them and I never lost an amp. I'm hoping the Peavey Tech's answer was more politically correct and more overkill than the tone he was using. I'm just a sucker for the mojo in bringing something old back to life. ;D

[musicallymrm]

Jun 17, 2009 19:45:28 GMT -5 ChrisK said:

The new speaker may seem louder since you're putting more power through it at a lower volume control level than with the old one.

It may also have a higher Spl rating (be more efficient).

It will work up to a certain level and then you'll start creating overheating in the output stage.

If you want to do the 4 Ohm trick, you can, but Radio Shack may not carry 4 Ohm 50 Watt power resistors.

They did have one rated at 4 ohms @ 30 watts. (SKU#271-120) That might be close enough if I decide to go that route to stop it from self-destructing at somewhat higher levels.

[ChrisK]

Rule of thumb; only operate resistors at a maximum of half of their rated power.

If they have an 8 Ohm 30 Watt resistor, you could use two of these in parallel.