50 Cal + issue

[twisted99]

first let me introduce myself my name is Steve and I am new to Boogies. I have been playing for about 14 years and have owned many tube amps. Mostly vintage stuff. Some of the notables are JCM800 2205, Hiwatt Custom 50 DR504OL, Orange Hustler 125, Carvin X-60B and many others.

I just bought a 50 cal + on the bay which was described as being in excellent condition but when she arrived I found out that wasn't quite the case. Rust on the screws, stains in the tolex, scratchy pots, and worst of all a high pitched squeal when playing on the clean channel if the treble is turned up past 5. I am thinking this is probably a tube issue and I have already ordered an entire new tube set from Eurotubes and I did all the normal maintanece I would do to an amp this age; cleaned the pots, tube sockets, and eq sliders. My question is anyone have any other ideas as what to look for?
By the way the lead channel is absolutely amazing and if I can get this squeal issue taken care of the clean sounds great as well. Definitely an underrated amp if it had been properly taken care of.

 

[MrMarkIII]

Hope you didn't use pot cleaner on the EQ sliders because that removes necessary lubricant. Just sayin'.
The tube in V1 or V2 is most likely microphonic. I'd start with those.

 

[twisted99]

Well since they barely moved before I cleaned them I don't think I caused them any harm as they are working great now. I will pick up some di electric grease to make sure they stay lubricated.
Thanks I was thinking it was the V1 and V2 but I have switched them out with some tubes I had lying around and still extremely noisy. but only when playing clean. The tubes I had lying around where just some old GTs that I took out of another amp for some reason. They might have been bad also. I will just have to wait till the JJs come in.

 

[user 7737]

Keep us posted... thanks...

 

[twisted99]

It was definitely a tube issue. Fresh set of JJs and the thing absolutely rips. Almost too much gain. I might switch to a 12at7 in v1 to try and calm it down a bit. The JJs really deliver in the power section and just like I thought with the new pre amp tubes the cleans are pretty amazing for what I thought would be a one trick pony.

 

[stomper]

Congrats on getting a very cool amp, and isolating the noise issue. My 50+ has been my main gigging amp for 19 years. Consider getting a Thiele extension cab. It improves the overall tone greatly. To tame the lead channel, try a 5751 tube. It has about 30% less gain than a 12ax7. Enjoy your amp!

 

[Gruffnutz]

Seconded on the 5751. 12AT7s aren't a great pre-amp tube IMHO. Better off using them in the phase splitter.

A 5751 will also give you a better balance between the clean and dirty channels.

.50 Calibers rule!

 

[polotska]

Just to clarify--are you guys suggesting using a lower-gain tube in V1 or V2? I've heard some suggest using a lower-gain tube in a .50 Caliber + in V1, others in V2, and am curious for other opinions on this matter.

 

[MrMarkIII]

V1 affects the lead sound, V2 the rhythm sound. It's backasswards from normal, and that may be where the confusion is coming from.
The reverb tube is a 12AT7 (it should be!), 40% less gain than a 12AX7. You could pull that tube, and try it in the V1 or V2 positions to see if you like the sound. The reverb won't work if there's no tube there, but it will resume once you put the tube back.
A "5751" tube offers 30% less gain than the 12AX7, 10% more than the 12AT7.
Here is a link with a bit more info:
http://thetubestore.com/gainfactor.html

 

[wallybob]

The schematic I have indicates that V1 is strictly used in the lead mode - V2 appears to be used in both rhythm and lead modes.

 

[wallybob]

double post - sorry

 

[polotska]

Thanks guys, that makes sense. I'll have to pick up a 5751 and give it a shot.

Anyone have any recommendations of brands to try? The JAN Philips 5751 at about $20 seems like the best option I've found so far.

 

[twisted99]

I switched in the 12at7 and it is much more to my liking. More than enough gain and now I can get that classic rock overdrive as long as I keep the preamp volume on about 2. I think I am gonna need to order a 5751 to try it out. I just switched my 12ax7 jj from v1 to the reverb for the time being and the reverb still sounds fine so I think I will just leave it like this until I can get a 5751.

 

[Tabster]

I know this is a bit late to enter this, but i use a 12aU7 in v1.....way smoother still extreme gain..great amp.. before I kept the lead gain at less than 2, now with au7 i run it at 5 or 6 and it has more compression, kinda violin like as compared to the grainy style it had before...but 90% of the time I gig with it I use the clean channel and pedals..that`s better yet :wink: