Monarch SA-30

jimbo1421

Does anyone know anything about the Monarch SA-30 tube amp. I will be going to check one out in a while. The seller says it needs high efficiency speakers to function well. Does the Monitor 7A (Peerless) qualify.

http://www.radiomuseum.org/r/monarch_sa_30sa3.html

It appears to be German made in the sixties.

Jim

jimbo1421

I went to give this a listen yesterday and took along my Monitor 7s. Everything appeared to work except for some scratchiness on the volume control. This amp definitely has the "sweetness of tubes", but otherwise sounded rather thin with not much bass output. It does have pre-outs so it could be paired with an SS power amp. Or maybe a powered subwoofer would give the necessary oomph. Seller is asking $140. I turned it down yesterday, but I could change my mind.

Any thoughts?

Jim

mhardy6647

Looks very Japanese inside - not unlike, e.g., the Japanese-made Realistic (Radio Shack) SAF-40. Those "shielded" output transformers and the spring-y clips to help hold the tubes in place are dead giveaways.

If memory serves, the "Monarch" amp was sold under various brand names, including Olson (an electronics catalog retailer, not unlike Allied, Lafayette, Radio Shack, or Burnstein-Applebee) and Herald. Probably pretty basic but not bad. I am guessing (!) push-pull 6BM8 outputs; that's good for about 8 watts continuous ("RMS") per channel. Otherwise, maybe push-pull EL84 (6BQ5), in the neighborhood of 12 to 14 wpc.

I would guess that it it is in dire need of replacement of at least all of its electrolytic capacitors and its inter-stage coupling capacitors. With original caps (especially if it has the very typical grey coupling caps used in early/mid 1960s Japanese gear) it is a time bomb. It would also sound much better after a rehab.

jimbo1421

Thanks mrh. Unless I come to my senses, this might be an interesting training project.

Jim

mhardy6647

Should be fairly straightforward (unless the amp actually has something wrong with it - I have someone's SAF-40C in the basement that I've been fiddling with, on and off, for two years now!). The only issue that the 1960s Japanese tube hardware often presents is cramped and complicated parts layout/construction below decks. For the ham-fingered (that'd be me), they can be a little tricky 1) to source suitably small parts (capacitors) for and 2) tricky to get stuff in and out of the rats nest of wiring.

Here's my stock example photo - this is the output section of an Allied/Knight 333 stereo FM receiver (built by Pioneer and also sold by them as the SX-34). It's a push-pull 6BM8 amplifier - sounds good but it was tricky to find coupling caps that'd fit (Panasonic has a line of small good quality caps that filled the bill). An integrated amp probably won't be as bad. The above-mentioned SAF-40C actually is quite cleanly laid out below decks (come to think of it)!




Compare the Pioneer to this "before" (re-capping) photo of the same area (output section) of a Fisher 400 receiver.



(you can probably guess which I enjoyed working on more...)

jimbo1421

Hi mrh,

Can you give me some idea of the cost of capacitors for a project like this, assuming some mid range company like Parts Express supplied them?

Jim