Dynaco Stereo 120

[speakerman1]

Well I hope to be taking possession of one of these little amps. This is a SS amp. Have been looking at the upgrades. Fast has any upgrades been done?

Larry

 

[speakerman1]

Trying to count how ICs I will need. I will change out the binding posts when it gets here.We shall see what will be done. Wish it had P to P wiring. There are a few kits.

Larry

 

[laatsch55]

You will never have enough and they will be all over the place.

 

[speakerman1]

At 145.00 a pair I'm not looking to get a bunch. If you know what I mean. Been testing them for months. Today is the 1st time I heard a difference. Nice surprise. LOL

Larry

 

[speakerman1]

Well it is here. Have to figure out a way to hook my speakers up. I have everything but binding posts. May have some cable ends till I get the binding posts for it.

Larry

 

[nakdoc]

No ICs in these! It is one of the few amplifiers with a regulated power supply. You will find it mildly whimpy and dark sounding. Check for vented caps.

 

[speakerman1]

Been running it about a week now. For what it is I like it. I don't like bright amps. It has a very sustainable sound. I stop and listen when something catches my ear. Watching Joe Bonamassa Live in New York's Beacon Theater

 

[Gepetto]

Dynaco had one early SS amp that capacitively coupled the loudspeakers to the amp rather than direct coupling. IIRC, it had an inductor wire wound around the diameter of these coupling caps.

Is this the one?

 

[speakerman1]

There is a cap that has ceramic insulation and it is right before the outputs. Very weird looking. Trying to figure how to get in there. My 1st time with a Dynaco.

Larry

 

[speakerman1]

Listen to Chicago in Chicago. I love these guys I have none of their music.

Larry

 

[Fast Forward]

It did OK powering my CV D3s,,,probablly some upgrades out there

 

[speakerman1]

I like it. I am happy and dude I do thank you.

Larry

 

[nakdoc]

Dynaco had one early SS amp that capacitively coupled the loudspeakers to the amp rather than direct coupling. IIRC, it had an inductor wire wound around the diameter of these coupling caps.

Is this the one?

The Stereo 80 and 120 both used cap coupled outputs, because they had a single power supply rail. The 80 was unregulated while the 120 was regulated. I have no clue why Dyna wound the output LPF inductor around a cap, unless there was no off the shelf part that could have been soldered to the board.

 

[Gepetto]

Probably wound it like that because it was cheap, deterministic and effective. I thought it was a pretty novel approach. Unfortunately damping factor suffers a lot when the output is capacitively coupled.

 

[wattsabundant]

The amp was available in kit form. Dyna saved the cost of a choke and supplied a length of wire for the builder to wire around the cap. I bought one of the last kit units in 1978with all of the fixes and it never gave any trouble.

There were over 100,000 120's shipped. When the early PC's came out with multimedia, I thought I'd become very wealthy by supplying a small amplifier for the computer speakers. A mosfet upgrade would be the ticket. I stripped a 120 and built a mosfet amp right out of the Iternational Retcifier data book. I pitched the old power supply and caps in favor of a split supply. I got it to work and made a prototype. Like always I never got past the prototype and didn't have a way of cost effectively getting boards made.

If anyone is interested I still have all of the old files including PCB info.

 

[speakerman1]

The amp was available in kit form. Dyna saved the cost of a choke and supplied a length of wire for the builder to wire around the cap. I bought one of the last kit units in 1978with all of the fixes and it never gave any trouble.

There were over 100,000 120's shipped. When the early PC's came out with multimedia, I thought I'd become very wealthy by supplying a small amplifier for the computer speakers. A mosfet upgrade would be the ticket. I stripped a 120 and built a mosfet amp right out of the Iternational Retcifier data book. I pitched the old power supply and caps in favor of a split supply. I got it to work and made a prototype. Like always I never got past the prototype and didn't have a way of cost effectively getting boards made.

If anyone is interested I still have all of the old files including PCB info.

That is cool.
I'm listening to it right now. In my eyes it is a pretty good little amp. For what it is I am enjoying it. The price is right. That is for sure. Thanks again Fast. Very nice amp.

Larry

Larr

 

[speakerman1]

Well here comes the upgrades. Just looking. It needs some work. I think I can make it a very nice little amp. Should change the wiring and there is corrosion inside. I hope with my new glasses I can solder. LOL

Larry

 

[Fairchild]

In some ways that reminds me of a Soundcraftsmen PCR 800.

Jim

 

[speakerman1]

Can you see this link?

http://www.cedist.com/products/S-CSK-AV35

 

[Fairchild]

Yes.

I have the D5 and the fader lube in the bigger cans.

Jim