Question to Robocycler and Eppendorf PCR machine owners

Robert Hartley rh at
Fri Jun 30 03:44:26 EST 2000

Hello Zoltan.

> We are thinking of buying a new PCR machine. We'd like to get one that
> is capable of testing a range of annealing temperatures in one run.

There are lots of machines that wil do this. MJR PE Eppindorph, BioRad and

The 9700 and MJR have a non linear gradient, but the RC has a linear
gradient and I found it to be the best of the three machines I tested
though the footprint of the machine is BIG.  

Most people I know who have gradient blocks say that they thought that
this was essential but after using one for a year or two they ALL say that
it was hardly ever used.

>I am leaning more towards the
> robocycler because it seems faster and the blocks are pre-heated (we
> have 3 PE 9700 and all 3 failed at least once so far). My boss is
> worried that the robotic arm will break down frequently. Any
> suggestions?

The robotic arms used to be a bit dodgy in the begining but are fine now.
The RC has a 1 year guarantee. Ask for a 2 year. Remember you are the
CUSTOMER and it is a buyers market. You should ask for the relevent
companies to give you a loan machine for a month to play with. 

This may sound silly but remember when evaluating the PE machine don't be
fooled into using their AmplitaqGold. It is a nice Taq but may make their
machine look better than it is compared to the other machines. Use the
same enzyme at all times.

THe machines are all much the same anyway. If you buy any of them MJR
PTC200, PE9700 or RC then you will have a mice machine.

The stratagene rep will probably mention that there is NO ramping time for
the robocycler due to the pre heated block  However this will only be
acheived in an H bomb :-) so the tech folk at Stratagene suggest allowing
a ramp time of 2C/sec for the ramping in the tube..

The Interface of the PE machine is VERY nice and easy to understand. The
RC is not. So if you want lots of people using it infrequently there maty
be some problems. 

In the end I chose a RapidCycler but for specific reasons. You may want to
get some of DNamp's Taq and mail Duncan (see this group for address). I
beleive he has tested all these machines and should give you some
optimised protocals for his enzyme to get the ball

> zoltan szabo

Bob; Sunny Scotland

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