I recently became aware that my PAS-3X didn't play well with my solid state power amps - mostly an early Van Alstine MOS-FET 150. There was definitely a rolling off of the lowest bass. This in spite of the mods recommended by Dynaco in the ST-150 and PAS-3 manuals. Everything was fine if I used my PAT-4, but this left me with an FM-3 and a PAS without a matching power amp. This started me thinking about getting an ST-70 to go with them.
Also, I don't have any tube experience in the stereo era so I was curious to find out what all the noise was about. SS has been good enough for me for thirty years.
I had been looking at ebay, but since my experience with ebay has been vaguely disappointing, I wasn't about to jump right in. About this time I saw Bill Thomas's build diaries here. He had just finished "Dimples", so named because of some long ago shipping damage. Of course, I was familiar with Bill through his posts on the Dynaco forum at Audio Asylum.
I emailed Bill and since I wasn't in a position to buy right then, we agreed that if "Dimples" was still for sale when I was ready, I'd take her, otherwise, he'd build another stock '70 for me. "Dimples" sold, so after a couple of units in line ahead of me he built another '70.
Well, I got it last week and it's fantastic! With a pair of A-25's I don't hear any of the "rolled off highs" or "flabby bass" I've read so much about. The workmanship can be seen in Bill's detailed build diaries here. I won't attempt to describe it in this post. There's one touch of craftsmanship he adds which I'll keep to myself.
It's like getting a new ST-70. No worries about needing tubes, leaky caps or out-of-value resistors, cold solder joints or no solder joints.
I'm really enjoying the full bodied tube sound. The only problem is that it makes the Yamaha RX-596 and Boston CR-9's which have been my daily driver for years sound "clinical", for lack of a better word.
Right now, I'm listening to Shostakovich's"Ballet Suite #3". If you want something to test the highs, lows and dynamic response of your system, this is one.
Harry Vaught
Maryville, Tennessee
