[Amps] More information for "What NOT to buy"..

dcoffman at iquest.net dcoffman at iquest.net
Tue Oct 24 08:54:47 EDT 2006


Robert,

Can you elaborate on the L4 conversions?  I guess I was unaware that the L-4 
floated the grids.  Also, the addition of the zener in the B- line.  Do these 
modifications just provide additional stabliity?

It has been my understanding that the power supply limits the output power to 
the old "input power" standard.  To obtain the legeal limit today, the power 
supply would have to be rebuilt.  Does it just not supply the current needed 
for full output?

Thanks,

Doug - N9XTF

Quoting "Robert B. Bonner" <rbonner at qro.com>:

> I think its pretty hard to beat a Drake L4B for a starter amp.
> 
> They were built pretty well.  The only weak link in the thing is really the
> Power supply caps as most need replacing due to age at this time.
> 
> An easy fix.
> 
> The layout is pretty good, it doesn't have 160 but it's a better quality amp
> than an SB-220 for close to the same price.
> 
> The Henrys will make more power, but they also are less forgiving to
> beginners because of this.  The learning curve is short however and a nice
> 2K-4 is a great 3-500Z box.
> 
> The L4B is easier to take apart and look around in, LEARNING AMPS.  Plus it
> has some funky practices utilized (floating grids) that could be eliminated
> and a zener added...  Nice mods that could make you feel involved.
> 
> Its easy to follow the schematic in the amp and the manual is easy to
> understand.  I still have a manual for one of these in my file cabinet.
> 
> I agree with all the other posts everybody has made.
> 
> This is a rather novel topic, almost everybody so far is in semi agreement.
> 
> While everybody has experience with most amps...  Most all of us recognize
> what makes a solid amp.
> 
> There's nothing quite like a several dozen 1625's glowing inside your box.
> 
> Whatever amp you choose, you must train yourself to always TURN THE POWER
> (DRIVE) control to zero before attempting to start tuning the amp.  This was
> an expensive lesson taught to a 15 year old who then spent $60.00 to replace
> the two 3-500Z in his L4 (1971)
> 
> Have a blast with amps...  But not a detonation.
> 
> BOB DD
> 
> 
> 
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