I really like Kiwame 2W carbons for grid resistors and Takeman 1/2W carbon films for everything else in vintage gear. For power resistors, you can't beat Ohmite Brown Devils (ceramic wirewounds).
-D
Tube newb Dynaco pt. 2
- Thread starter bored184
- Start date
I really like Kiwame 2W carbons for grid resistors and Takeman 1/2W carbon films for everything else in vintage gear. For power resistors, you can't beat Ohmite Brown Devils (ceramic wirewounds).
-D
Are the grid resistors the resistors found soldered to the tube sockets themselves? What are the power resistors?
The bias section was replaced over the weekend. I will get photos up later this afternoon. It ran a pair of SDA SRS 2 for about an hour last night with no problem. Other then the bias section what voltages should I check to make sure I installed the bias section correctly?
autocomman
New Member
Ive never heard one stock my was so trashed when i got it. But i have the tubes for hifi bored in mine and the fat bottle rca's and output transformers that were in it, new choke and power transformer...JJ input tubes and JJ rectifier tube....im more than pleased with it, and its a work horse. You cant go wrong with just a driver board update
Mark
Mark
Sorry for the lateness of this response.
Grid resistors are those resistors that connect to the grid of the power tube - in a Stereo 70, that'd be the 1k Ohm resistors that connect to pin #5 on each EL34/6CA7 tube socket.
The power resistors are the resistors that are attached directly to the terminals on the can capacitor - 6.8k ohm and 22k ohm resistors in the Stereo 70.
-D
I am resurrecting this thread because I am finally able to restore this amp. I am looking at carbon film resistors for the board, is their a difference between one manufactures carbon films vs. another. Also the board originally has .25 and .5 watt resistors is their any gain in going with higher watt resistors?
sKiZo
Hates received: 92644 43.20°N 85.50°W
Never been too particular with carbon film as they're all good.
If you've never had any issues with resistors burning in the original circuit, I'd just stick with what's there for ratings, or maybe double up at most if you don't have a particular value in the correct wattage. It's usually not critical as long as you substitute within reason, and will have zero effect on what you hear.
Not to forget, some resistors are meant to burn if there's a problem, acting as fuses to protect the more expensive components. Things like bias resistors for instance - rather lose one of those than a tube ...
If you've never had any issues with resistors burning in the original circuit, I'd just stick with what's there for ratings, or maybe double up at most if you don't have a particular value in the correct wattage. It's usually not critical as long as you substitute within reason, and will have zero effect on what you hear.
Not to forget, some resistors are meant to burn if there's a problem, acting as fuses to protect the more expensive components. Things like bias resistors for instance - rather lose one of those than a tube ...
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The reason I recommended the resistors that I did is that they are well engineered and reliable (especially the Ohmites). I'd rather have reliable than esoteric.
And just a suggestion - if you have two Stereo 70s, you should restore one to more-or-less stock and then mod the hell out of the other one. Listen for a while and decide which to keep. I know which one I'd lean towards, but you have to trust your own ears.
-D
And just a suggestion - if you have two Stereo 70s, you should restore one to more-or-less stock and then mod the hell out of the other one. Listen for a while and decide which to keep. I know which one I'd lean towards, but you have to trust your own ears.
-D
Thanks! My plan from the beginning was to keep one stock but I would like to rebuild the board with slightly better parts. I was hoping to order all my parts from one location but appears depending on what brand/type of resistor I go with I would have to order from multiple sources.
PC 3 board Parts List so far:
New board was obtained from a fellow AKer
716P/600V Orange drops for the .1 and .05uf Caps
Silver Mica for the 390 and 82pf Caps
Ohmite carbon film resistors for the board...playing with the idea of takman as well
New tube sockets, probably ceramic
Missing anything?
Shadowdog
Super Member
You may want to keep the original tube sockets if they are in fairly good shape(just tighten pins with dental tool etc) as imported ceramic (probably your only choice) usually are of poor metal that doesn't hold tension for long etc. and other problems like poor fit for the tube.
I resistor shop by price. The cheapest ones in the value I want are the kind I buy. I seem to end up with a lot of Stackpole resistors. No clue if they're considered cool or not, but I haven't had one measure out of spec, go in noisy, or explode yet so I guess they're OK. I do the same thing with silver mica caps and a lot of other basic type parts. It almost always all comes from Digikey too since I can figure out their filtering system. The last silver mica caps I got were CDE I think.