Recent content by djoffe

Here's an alternative: https://www.updatemydynaco.com/storeindex.html#RY301

I have some old data books to check for compatible info...maybe more info later.

A google search turned up this: https://www.el-component.com/bipolar-transistors/2sc1628-o saying further that: You can replace the 2SC1628-O with the 2N6557 or 2N6558.

This kit may be of interest to DH-101 rebuilders and hot-rodders: https://www.updatemydynaco.com/storeindex.html#DH101RCA

There are too many variables here for me to be comfortable with a blanket statement about this. Regrets...

F sub t is the frequency where the beta (Ic/Ib) goes to 1. At low frequencies, it might be typically 100-300 or so...It goes down with increasing frequency.

I went back into the PDF, and got a little closer...but not a perfect match: Another good reference starts on page 450, but it doesn't include the D44T7...but we are getting closer!

The D44 part of the part number is quite familiar. The "T" portion throws me for a loop. I did find this 1985 GE Transistor catalog online. Page 39/866 lists "power Transistors Complementary Pairs"...

A number of folks have applied this upgrade to the RCA jacks... https://www.updatemydynaco.com/storeindex.html#DH101

of course, it could also be oscillating, and it could have just some bad/shorted parts. Note that if the bias adjuster pot opens up, the bias current will be crazy high... BTW...measure current fairly quickly so heating does cause further damage. Also...measure current with no speakers connected.

on the "hot" channel...pull a fuse, and substitute an ammeter...measure the no-signal DC bias current...Enclosed file has details. My guess is that the bias current is crazy high....

Maybe a little useful info here: https://www.updatemydynaco.com/Citation12.html

Excellent! Glad to hear of your success...

At mid volume, the driving point impedance that the amplifier sees is highest. That allows more efficient capacitive coupling of hum into the amplifier input net. Sometimes, you can disrupt a lot of that if you can ground the body of the volume control pot. Usually, it's possible to solder a...

Is it quiet a min and max volumes? Is it noisiest at mid-volume settings? Does the noise seem like all hum?