Dynaco ST-70 and Magneplanar 1.6QR

Andersd...Volume means voltage gain (not really power) so it's possible that your preamp is just not driving the power amp with enough signal. One thing that you could try would be to connect your 4 ohm speakers to the 8 ohm outputs of the power amp. This will get you more voltage to the speakers although the power amp wattage capability (which may not be the limiting factor) will be less.

It's a long time since I played around with tubes, but I suspect that there is a 12AX7 input stage in the power amp. I hope you don't have a 12AU7 pluged in by mistake: that would lower gain. The driver for the output stage is probably a 12AU7: they might be swapped around.

You really ought to be able to play those speakers loud with your amp, and the symptom of insufficient power would be distortion, particularly clipping, rather than low volume.

All this being said, I still suggest you try a much more powerful amp, and find out how good your speakers really are.

Eldartford, which adcom amp are you using?

A

Andersd...My amp is the GFA-5503, which is the three-channel version of the GFA-5502 that you probably want. These amps are rated at 200 watts into 8 ohms, and 350 watts into 4 ohms (which is what the MG 1.6 are). I paid only $875 for my amp which was "B stock" (demo or mfg repaired) and it came from an authorized dealer with full warrantee, and I have no problems. (Someone "broke it in" for me, if you believe in that).

Magneplanar speakers are a very "easy" (resistive) load for the power amp, so I doubt that some of the very expensive amps would do much better than the Adcom when used with Magneplanars. If you were driving the MG 1.6 with the Adcom you would have a valid basis of comparison if you ever were to consider one of the very high end amps.

Go look at the Adcom website www.adcom.com for full details.

Elartford,

Thanks again, your advice is really appreciated as this is a "on a budget mission" .. I found some 5503's at better prices than the 5502, is there any drawback or benefit for me to go with the 5503 vs the other? ,
also what do you think of the 555?

Lastly, here is a curious thing. Some time ago I emailed Jolida to ask if they had a tube amp that could drive the 1.6s./. they answered as below.

The 502B, 801 or the JD 1000A could easily drive them.
 
Michael Allen

I dont know what to think?

A

If you can get the 5503 for less than a 5502, do it. The amp doesn't mind having one channel unused. Also, if you ever get into multichannel sound, the 3 channels will be useful.

The 555 was very well regarded when it came out, but that's a long time ago. I think you would be better off with a current model.

Regarding Jolida...any amp will "drive" the MG 1.6, but not all will do it in a way that extracts the full capabilities of the speaker.