Peavey 5150 Combo 2x12" needs servicing?

[guitarman78]

Hi there,

I have got an old Peavey 5150 Combo 2x12" speaker amp bought over a decade ago from Swee Lee. I can't help it but noticed that the amp has somehow lost abit of it's "bite" in it's sound.

1. Is it because the tubes are too old?
2. Does amplifiers need some form of servicing after some time?
3. If so, what do they usually during servicing?

Regards
Guitarman78

 

[Dongara]

If you have had it for ten years, then I'd suggest you change the complete set of tubes - preamp and poweramp. Tubes will loss their response (or 'bite') over time and when you can tell that there is something missing then that's a pretty good sign to change them. The power amp tubes wear out twice as fast as the preamp tubes so only change the preamp tubes every secongd time you retube the amp.

It is an easy job. Disconnect the amp and leave ift for a good hour after playing for the temperature to drop and the voltages inside to dissipate, then reach around the back of the amp and gently jiggle the tubes out of their holders. If I remember rightly, your amp has two power tubes (6L6's) and a number of preamp tubes (12AX7's). Buy a set of matched 6L6's and a set of 12AX7's. The 12AX7's can be any brand - jj's, EH, Sovtek - whatever your budget.

You can get these from Martin Electronics at Burlington Square opposite Sim Lim Square. I think that they are still there on the first floor. Maybe check the white pages first.

If this gets the tone back to what you remember, then that's it! No more work needed. If not, update me on this link and I'll try and help you out some more. The amp is not old enough to need anything serious like a cap job or any further servicing.

Have a great time learning about your amp.

cheers,

Mark.

 

[guitarman78]

Hey Mark,

Thank you so much for sharing your knowledge! I'll try to open up my amp and check out where to purchase the tubes. As far as I can see, there are 2 Tubes at the back of the amp. There are also 4 metal cylinders which I am not sure if it's a housing for the pre-amp tubes. Need to open up to take a look.

Regards
Glenn

 

[Dongara]

Hi Glenn,

You are right, the preamp tubes are inside the steel covers and the two large tubes are the power tubes. You can push the steel coversinto the amp and rotate them and they will come off.

cheers,

Mark.

 

[relinquish69]

5150s are really loud for home use. have you been using it often?

 

[guitarman78]

relinguish69 - You're right, it's quite loud. I use it quite often but and I can't raise above vol2. Why, you interested ah? =P

Mark - I found the 5 x pre-amp and 2 x power tubes. Thanks for the tip yeah?

 

[Dongara]

Hi Glenn,

Glad to hear that you sorted out the preamp tubes. You might like to put an attenuator ofn this amp so that you can run it around 5 or so and let it 'run' a bit. I have advised friends to look for the Trainwreck licensed Airbrake units - licensed by Dr. Z at the moment. I have heard them on an original 70's Marshall Super Lead 100 and a Fender Hot Rod Deville and it is the most transparent attenuator I know.

Ken Fisher was a close friend and these units are bomb proof, so if you can find one on eBay for around $200US, buy it as you will not be disappointed. The amp you have really rocks when you drive it (I heard it at recording studio a couple of years ago running flat out) and you missing out on a lot.

Wishing you a lot of fun.

cheers,

Mark.

 

[relinquish69]

I used to own a 5150 but it's too loud for home use. The really sweet crunch tone is after 7. By then my entire room would be shaking.

I still think the tone is beyond awesome though.

 

[edgie]

@guitarman78: Should you need to have your amp serviced beyond just replacing tubes(I hope it's not the case now for you or you'll spend quite more), you can look for Goose here in this forums. gsonique@yahoo.com.sg.

 

[guitarman78]

Ok, I'm trying to read up abit more on Tubes. 6L6 and 12AX7 eh?

http://en.wikipedia.org/wiki/Vacuum_tube
http://thetubestore.com/gainfactor.html

There is so much to learn besides guitar techniques man... Thanks guys for all your input!

 

[Dongara]

Don't worry about the tubes too much. They range in price from reasonable (for current production in China and Russia) to absolutely ridiculous for NOS (New old stock production from the 50's and 60's).

Start off with the value for money ones - Winged 'c' power tubes are good, as are JJ 12AX7s and EH 12AX7's - and they won't break the bank. Be very careful about NOS as they actuall make copies and some of them are in lousy condition. you can also drop the volume of the amp by using 5751 (military version of 12AX7 - gain of 70) tubes instead of the 12AX7 (gain of 100). This way you can turn the amp up more and geat more power tube drive.

Anyway, have fun.

cheers,

Mark.

 

[junkiemanxl]

+1 to Dongara


Good info mark

 

[Dongara]

Thanks Junkie.

That's the whole game of the forum - share experience (good and bad!) and hopefully we'll all get to enjoy playing more.

cheers,

Mark.