Summary:
In my opion this reviewing site should update to the new model number.
I have been using this amp for over a year and have no plans on replacing any time soon. I've owned and own many Dynaco products and I'm amazed at the price people are paying for them these days. Before I would pay $300 dollars for a 30 year old Stereo 70, even if David Hafler built it himself I would check the A-4 out. Look, the only way to make the Stereo 70 safe is to replace about everything under the cage, but the transformers. That list would include new boards which are about $79, new power supply caps at at $50,and of course new tubes which would be close to $100. After all that money and work the amp still has thirty year old transformers switches etc..
Don't get me wrong in its day the Stereo 70 was a rocking amp but the magic is in the tubes not the name.

Strengths:
If you like el/34 tubes I think you might like this amp. NOTE THE A-104 HAS BEEN DROPPED THE NEW AMP WAS INTODUCED LAST YEAR AND IS CALLED THE A-4. The new amp uses American made transformers. Although this is a 30 watt per channel amp the transformers are much larger in size than the ol'e stereo 70's.

Weaknesses:
This "kit" was hard for a novice (me) to build.

Similar Products Used:
Dynaco St 70 & Mark IVs plus most amps using el/34s tubes.

Summary:
I recently finished putting together the kit version of this amplifier with very few glitches. The design is a straight forward push-pull, utilizing 12au7's for drive and EL34's for the output. The power supply is solid state with a regulated bias circuit. Power is rated at about 35 RMS/CH.. I immediately begancomparing this amp. to my Tandberg 3000 Mosfet equipment driving a pair of ADS
L1290 speakers. As I suspected, the bass was less dynamic and defined with a hint of attenuated high end. I did find the midrange very smooth and listenable.
I was very impressed with how quiet the amp. was with no signal. I do plan,
in the near future, to replace the power supply caps. with 500v versions vs. the
450v supplied, and the signal caps. (metallized poly.) with 716P film & foil
poly. versions.
In comparing the kit plans to the few dyna's I have built, the instructions
were not as detailed and demanded a fair working knowledge of schematic diagrams. No detailed pictorials of the chassis layout were supplied like the old Dyna kits, but enough information is supplied to get the job done. The parts
seemed to be good quality along with the fit and finish. Overall this is a nice sounding amp., for this design, and did not exceed or fall below my expectations. Let the tweeking begin. (If possible!)