I would only worry if one runs hotter than the other. Also, a low impedance load may cause them to run warmer.
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I want to thank you for your responses and to those who responded privately. I spoke with David Alexander earlier today and he is going to help me figure out if there is a problem. Fortunately I live in Southern California and the MBL repair center isn't far away. Again thanks to all.
I want to thank my fellow MBL owners for taking the time to discuss my question and I want to let everyone know what I have learned. Actually Rwwear's analysis above appears to have been correct. Since both amps do operate at the same temperature and since the sound produced by the amps is absolutely gorgeous, it seemed very unlikely that anything could be wrong. As I mentioned, I am using each amp in stereo mode since each is driving a Dali Megaline speaker. For those not familiar with the operation of the Megaline speakers, each tower requires 2 sources of amplification. One amp powers the woofers of the tower and the second amp powered the ribbons of the tower. Therefore, you must have either 2 stereo amps or 4 mono blocks to power the Megalines. The minimum power recommended by Dali for each Megaline tower is 200 watts, 100 watts for the woofers and 100 watts for the ribbons. I listen at a fairly high volume level and this is putting a pretty heavy load on each amp particularly since I am using each in stereo mode. Prior to posting my question, I was at the Rocky Mountain Audio Fest, and I discussed this with David Alexander and I checked out the operating temp of the 9008A's that MBL was using to power the MBL 111 speakers. They were warm, though not quite as warm as mine. I was surprised that all the 9008A owners who posted here find that their amps are cool to the touch, because the pair at RMAF were certainly not cool though not as warm as mine. It appears that the warmth of the amps is related to the load that the amp is being asked to drive, and I have no doubt that the MBL 111 is not as difficult to drive as the Megalines. Each Megaline tower has 12 woofers and 3 thirty inch ribbons. Previously I was using 4 Atma-Sphere MA-2 mono blocks which are each 220 watts to drive them and they were putting out a lot of power. Likewise my friend Albert Porter is using 4 VTL 750 mono blocks for his Megalines.
We are certainly fortunate to own MBL equipment. The MBL amps are the best sounding solid state amps I have ever heard and I was a dedicated tube guy. Until I heard the MBL's I was convinced that I could never find a solid state product that I could enjoy as much as tubes, but I have found it with MBL. My wife's description is "breathtaking" and I agree with her. Also David Alexander and other MBL representatives have been very helpful even though I did not purchase the amps new from a dealer. My problem now is that I want more power for my speakers and that can mean only one thing. MBL 9011 amps!
I would concur that you may need two more amps. The MBL amps in stereo mode do not have much power or current capability at rated output (130/220/340). Peak output is another thing altogether but they really perform their best as monoblocks. Perhaps you can combine 8011AM or 9007 for the top and 9008A for the bass? Also, 9011 amps in stereo mode will still face the same problem as your 9008as. If you examine the rated output the 2 amps used in stereo mode are almost the same.
I had overbuilt 100W Class A amps on my MBL 101E speakers and while I knew they were not able to drive the speaker adequately, this became clear only after I installed amps with much more power.