Studio 22 questions

[Wildwind]

New guy here, long time Boogie player.

Two questions:

What is the difference between a .22 and a .22 + ?
Why do some .22s say "Class A Power" on the back? Mine does not.

Mine is a 22+ - the + is silkscreened, but is almost an inch away from the rest of the name. I've seen other photos where the + is much closer. I don't know if this is significant. My amp does not have an EQ.

Thanks to any who can answer these questions.

Greg

 

[Joey707]

The 22+ has a lead master control. I believe the reverb tank was moved from inside the chassis to the side panel of the amp. There be other things that I'm not aware of.
The + does not mean that the amp has eq.

 

[Wildwind]

Any ideas as to why some Studio 22s say Class A and others (like mine) don't?

We did a Class A mod to mine - very nice upgrade, totally switchable.

 

[RR]

We did a Class A mod to mine - very nice upgrade, totally switchable.

I don't mean to contradict if your Studio .22 is now true Class A, what changes was done to your amp since I'm not an amp technician but wouldn't the tranformer need to be changed out from a Class A/B to true Class A?

'Cause I sure would like this modification too (turn to Class A) and include a rectifier tube switch from diode / rectifier tube.

As for yours saying "Class A", maybe an early production of Studio 22s, I dunno know, not sure, mine doesn't.

 

[Wildwind]

I realize there is controversy surrounding Class A at times, and I'm not knowledgeable in this regard. I'll tell you what we did in primitive terms (my level of understanding).

A switch was installed that renders my amp as cathode biased (as opposed to whatever Class A/B is) - and there is some simple circuitry activated by that switch. The mod does have a substantial effect on the sound and it does demonstrate the main Class A characterisitcs - more transparent high end, less mid-range emphasis with considerably more clarity (the most noticeable change), and a cleaner, tighter bottom end. It is very reminiscent of a Mesa Maverick - which is placarded as Class A.

It also demonstrates Class A characteristics in the breakup of the clean channel - at about 6 or 7, it moves very sweetly into an edginess usually associated with such amps. This movement does not change the timbre of the amp - very musical.

So while I'm certain it isn't true Class A, it isn't bad.

The mystery as to why some Studio 22s and 50s say Class A and some don't remains. I haven't seen any pattern as to production dates. My friends Class A 50 is newer than my non-Class A 22. The amps are otherwise identical in appearance (though his does have a graphic) other than two extra EL84s and a larger transformer. I've never seen a non-Plus, Class A placarded Studio 22.

 

[RR]

Thanks Wildwind.

Your explanation is excellent. I've should not have said "True Class A". I'm aware of Class A controversy with Vox type amps which will include Mavericks, and what have you => Matchless DC30, LoneStar Special.

But that was not my objective, more I wanted hear your your modification and now intrigued by it. So you were able to stay with a stock output transformer?

Thanks

 

[Wildwind]

You're most welcome - I'm glad I was able to explain it. I wasn't sure if I could.

There were no changes to the transformer or any other circuitry. Total parts cost was under $20. It was done by a friend who has modified amps for his own use and amusement for many years. He did have to very slightly enlarge one chassis hole (usually reserved for the EQ switch) to mount the heavy-duty single-throw toggle. I doubt if anyone would ever spot it and you could still restore it to stock appearance, which was one of our goals - not that I plan on selling this. With the Celestion Century Vintage speaker, this amp now weighs under 32 pounds - will probably blow away in the wind if used outdoors - and will kill tonally in both modes. This one is a lifer.

Greg

 

[RR]

Wildwind:

The more you talk, the more I get curious I get. (in a good way).

Now I'm curious about those Neodymium magnet Celestion Vintage Century speakers. That sure would save my chronical back pains.

 

[Wildwind]

The Century Vintage speaker is nearly identical sonically to the Vintage 30 of fame, according to Celestion and the guy who I bought it from. Paid $99 plus $8 shipping from Avatar - that might be cheaper than a regular Vintage 30 these days.

This speaker weighs about three pounds. My amp now weighs 31.5 pounds ready to go. I love the way it sounds. The stock speaker was awful.

The mod is pretty easy I think, but I don't know any details. The guy who did it probably got it from somewhere else and adapted it to this amp. He's done several mods like this to various amps.

Greg

 

[RR]

Thanks for the info Wildwind.

Spare me the details on the modification on the Studio .22. I'll likely build my own dual EL84 "ClassA" amp and leave the Studio .22 alone.

http://www.18watt.com/
http://www.ax84.com/ :wink: