Fmj, I had a ML-32 for over eight years in my system and it was always left on, not in standby mode, and I have no memory of it ever running hot in any way, including the isolated power chassis.
So, I would have it checked over for a possible malfunction, otherwise this does not make sense to me why you are experiencing this problem.
I don't know about incredibly hot, but mine does run surprisingly warm for a solid state device. I keep the power supply/control box and the actual preamp box on separate, open shelves, so I don't worry about ventilation. I leave mine active all the time.
Describe what you call really hot? If you can keep your hands on the unit all the time the unit should be fine. I had a 32 for a year and wish I had never let it go, and was surprised at how hot it ran. Should be fine as long as the have proper ventilation.
hope this helps,
I currently own a ML-32 and have been experiencing a similar issue. I have owned my ML-32 for 3 plus years. During this time it has performed flawlessly. In February of this year while putting the unit into stand-by I noticed that the right side of the controller was very hot to the touch and the left side was only luke warm (normal). Up to that time, both sides ran cool and dead quiet. In addition to the heat, I could hear a high pitched whine coming from the unit on the right side. I have had the controller and pre-amp back to Levinson two times over the last five months with no resolution. They keep coming back saying that everything is fine and within tolerances. They said that they could not duplicate the heating nor hear the whine! For your information, the units are kept in an open environment with great air flow around the units. I have had electicians out to check my dedicated circuts up and down for power issues or loose connections. I have tried other outlets, and even taken the unit to a friends house to see if it was something in my house causing the isssue. It is still the same, heat and whine on the right side. I have changed power cords, disconnected all connections to the unit, had Levinson send new power supply cables (possible loose pin or bad connection). All of this has not changed the issue. As of today, it is once again on its way back to Levinson for the third time. Levinson has offered to send out a reconditioned unit in exchange but I declined. They were frank in telling me that the unit had experienced over-heating issues!!! I am a loyal Levinson fan and they have bent over backwards to try to resolve this issue but my patience is getting thin.
all levinson gear runs warm in stand by mode
I use a Krell preamp with separate power supply and it too runs hot and has no on/off/standby switch, always on. It runs in class A mode.
One thing Krell says is never use a fan! It screws with the bias.
thanks for your responses.
to clarify, only the power supply unit is hot. and it is very hot to the touch, including the control knobs. It is uniformly hot (both sides) but I have not heard a whine noise at all.
I know that the unit should be ventilated well but I have it in a large enclosed cabinet with air/space around the unit. This is not ideal but should not produce the heat that this power supply seems to produce. I use the cabinet for other equipment and have had a variety of components / units in there and the only one that has ever been warmish is the ps audio p-500 (which seems to get hot whereever it may be). The power supply of the ml32 is much warmer.
Piperdan, what did Levinson mean when they told you that the unit had "experienced over-heating issues"? Also, could faulty DC connections/cables be a culprit to this problem?
Any other suggestions of things to look for before it goes back? I love the sound and would like to keep this unit.
I had a similar experience to Dan. One side ran much hotter then the other, and the unit had a "whine". After sending mine back for the third time, my dealer convinced Levinson to provide me with a refurbed/restock unit (both pieces). I haven't had any problems since, but the controller will throw off some heat in standby (which the cat loves...). Bottom line, if you can't keep your hand on it, something's wrong.
I bought a used 32 about two weeks ago. I left mine in
stand-by and it runs warm but not hot. I keep the two units
side by side on the same shelf and there's proper ventilation.
I think that the whine is a clear symptom that something is
going wrong. I own a ML-36S DAC, a ML-331 power amp and a
ML-31.5 transport too and I've noticed that the 36S and 32
reach about the same temperature while in stand-by. The 31.5
is not warm at all and the 331 is significantly less warm
than the 36S and 32 (surely because it's designed to have
great heat dissipation).
its biased pure class a thats why it runs hot dont worry about. biasing at pure class a is why it sounds so good
Most linestage/preamps are Class A biased. Given the low output of linestages, excessive heat is normally not an issue with solid state linestages. Besides, with the Ref. No. 32, the amplification stage, input switching and volume resistor ladder is in the box that Fmj said is not hot. The box that is hot is the power supply/logic control circuitry box.
The power supply box does get somewhat hot, but the kind of heat Fmj is reporting (even the knobs are warm to the touch) is not typical of normal running condition.
Chris, it seems that you have an unusually hot running reference control unit. This is not normal, I've had mine in stand-by mode and on since February this year and it never gets "hot", only warm when on and then equall temperature right, left and middle. The control knobs on the front never get even warm on my unit. Go back to ML and ask them for advice, it could be your amp circuit, make sure that there is no risk of excessive wear.
As for Dan, his unit seems to be faulty, or there is something else wrong in his setup...I would take the recondition unit, as long as ML gives full warranty, only then he may find out if its really the controller box or not. Also, why not have the dealer do all this for you...for a $16k pre-amp he ought to!!!