[m]

I auditioned a pair of these in my system. Very nice sound. Does anyone
here have experience with the long term reliability of these, or other
Manley Labs gear?

Thanks,
-m

[Serge Auckland]

m wrote:
I auditioned a pair of these in my system. Very nice sound. Does anyone
here have experience with the long term reliability of these, or other
Manley Labs gear?

Thanks,
-m

My knowledge of Manley equipment is limited to their Pro-Audio stuff,
which works pretty much as described, as seems to be reliable. Pro users
won't consider anything that isn't reliable as their living depends on
it working.

100 watts from 4 EL34s is somewhat high, but not unreasonably so. I
would pay attention to checking bias regularly as the manual suggests.

The output transformers look to be a decent size, and their specs, if
achieved in practice, would indicate a solidly engineered product.

S.

[BEAR]

m wrote:

I auditioned a pair of these in my system. Very nice sound. Does anyone
here have experience with the long term reliability of these, or other
Manley Labs gear?

Thanks,
-m

My experience with Manley and VTL is that they set up their tube amps to
have a rather highish output power rating. Good for marketing.

Given the real world capabilities of import "EL34" tubes, this means
drastically shortened tube life, or spectacular tube failures in many cases.

I have had a number of amps of this sort brought in for repair, and in
general the deal is that the screen ratings are exceeded by a fair
margin if you push the tubes to get 50watts per tube out. Along with the
higher screen power, they tend to set the B+ on the high end of the
usable range. If you set some sort of limit on the screen dissapation,
then the power output (not surprisingly) is limited back down to the
"normal" rating.

Most people seem to think they need the extra few watts for reasons that
are unclear to me.

The difference between 70 watts ("normal power") or thereabouts, and 100
watts in dB is just a bit more than 1dB. Hardly worth worrying about.

Beyond that the VTL transformers I have tested seem very nice. Manley
and VTL have a relationship historically, so they may be quite
comparable in most areas.

I'd personally not want these amps myself, or if I did, I'd certainly
have a good technician modify the screens for reduced dissapation and
longer tube life.

Of course, this is just my opinion.

_-_-bear

http://www.bearlabs.com

[Mike Gilmour]

"bear" wrote in message
...
m wrote:

I auditioned a pair of these in my system. Very nice sound. Does anyone
here have experience with the long term reliability of these, or other
Manley Labs gear?

Thanks,
-m

My experience with Manley and VTL is that they set up their tube amps to
have a rather highish output power rating. Good for marketing.

Given the real world capabilities of import "EL34" tubes, this means
drastically shortened tube life, or spectacular tube failures in many
cases.

I have had a number of amps of this sort brought in for repair, and in
general the deal is that the screen ratings are exceeded by a fair margin
if you push the tubes to get 50watts per tube out. Along with the higher
screen power, they tend to set the B+ on the high end of the usable range.
If you set some sort of limit on the screen dissapation, then the power
output (not surprisingly) is limited back down to the "normal" rating.

Most people seem to think they need the extra few watts for reasons that
are unclear to me.

The difference between 70 watts ("normal power") or thereabouts, and 100
watts in dB is just a bit more than 1dB. Hardly worth worrying about.

Beyond that the VTL transformers I have tested seem very nice. Manley and
VTL have a relationship historically, so they may be quite comparable in
most areas.

I'd personally not want these amps myself, or if I did, I'd certainly have
a good technician modify the screens for reduced dissapation and longer
tube life.

Of course, this is just my opinion.

_-_-bear

http://www.bearlabs.com

It's always interesting to hear from people who have repaired VTL
amplifiers. After reading that post I went back to the VTL book written by
David Manley where he states " We run the tubes with less standing-current
but with proportionally higher rail voltages which, in turn, requires
higher bias voltages which produces the desirable combination of the highest
power with lowest distortion 'at power' while still running cool and
ensuring long life"

He also goes on to say that the bias winding is interleaved with the B+ rail
winding for a gently self-adjusting negative bias that smoothly tracks the
voltage of the B+ rail according to variations in line or mains voltage

Obviously the reality is somewhat different.
I've never owned VTL's myself being quite content with Ray Lumley's
reliable and good sounding creations (with suitable modifications of
course).

Mike