diytube.com

Well Tom I guess we each have our preferences. I think one needs to look back and realize the Dynaco is dated and that the driver boards have served their time. As for the heat causing the components to degrade we could both argue that. Age would enter into the picture as being a prime factor. Unfortunately components don't have a life of 100 years or my Atwater Kent radio would still be like new.

If you would like to go into this deeper I would be more than happy to wire up my Blackburn board and take some temperature measurements for you. I believe you will find that the heat that you seem to be worried about isn't going to be causing near the problems that you fear.

I did not know Blackburn is out of boards, that’s unfortunate. I used one on a rebuild of a ST-70 and really like it. Nothing overly fancy just good quality components and a bit of a rework on the power supply. There are another couple of JJ caps under the chassis (47uf first stage and another 100uf-100uf). I spent a lot of time and effort on the finish. Had the transformer end bells blasted, clear coated and the chassis painted with textured graphite paint. All of the hardware is new; well really everything is new except the transformers and chassis.

I went with mounting the Solens under the chassis and the Russian PIO’s above mostly because they did not fit.

Before Picture:



After:




Full Gallery:

http://www.shaneaune.com/modules.php?name=gallery2&g2_itemId=274

The Blackburn circuit is very easy to wire point to point. Plus you can make room for the large green PIO caps!

That's some nice work. I like the concept of the ground wire right across. I have another ST-70 wanting a rebuild and I just may try that out. I used the 500V Russian PIO's. I assume those are the 800V or 1000v. If you could fit those I would think the .22uf Russian Teflons would fit.

Those are the K75-10 .22@ 500v caps. The K42Y caps are much smaller. Both sound excellent!

If it is not too much of a bother could you please post a picture of the top of the board? I just want to see how you have the tubes laid out. I am going to order up the parts and give it a shot this week.

No problem! The center tube is the phase inverter. I also started on the 12AU7 version but it got side tracked.

Nice! That sure gives it a nice clean look on top. I ordered the parts today so I just have to find a piece of metal to start cutting up to fit.

Thanks for the idea, for some reason I never thought of that even after conversing with burnedfingers about his homage to the Maple Tree board.

Does anyone have a schematic or manual of the 12AU7 version of the Blackburn audio ST-70 board. Blackburn has the 6SN7 version on his site.

Thanks,
Sal

Sal Brisindi wrote:Does anyone have a schematic or manual of the 12AU7 version of the Blackburn audio ST-70 board. Blackburn has the 6SN7 version on his site.

Thanks,
Sal

I got it...mail me for a copy

Arne K