I would change that 10K bleeder resistor to 100K or more, right now it is probably drawing as much current as the entire rest of the amplifier circuit will when complete.
I don't recommend over running that transformer by connecting the 15V secondary of the mains operated transformer to the 12V "primary" of your step-up transformer as this could push the core pretty close to saturation. Good way to let out the magic smoke.
I think you are actually close enough as the actual load current is not going to be that much higher.
I don't recommend over running that transformer by connecting the 15V secondary of the mains operated transformer to the 12V "primary" of your step-up transformer as this could push the core pretty close to saturation. Good way to let out the magic smoke.
I think you are actually close enough as the actual load current is not going to be that much higher.
Kevin,
Thanks for your input, just the advice required.
I have heard what happens when you let the magic smoke out, so I'll leave the transformers as they are
I would like to leave a bleeder in the circuit, helps to reduce the possibility of those touchy, feely moments
I'll look for at least a 100k resistor for this. Current load for this circuit is 43mA, as far as I can find out from some websites.
DerFly.
Thanks for your input, just the advice required.
I have heard what happens when you let the magic smoke out, so I'll leave the transformers as they are
I would like to leave a bleeder in the circuit, helps to reduce the possibility of those touchy, feely moments
I'll look for at least a 100k resistor for this. Current load for this circuit is 43mA, as far as I can find out from some websites.
DerFly.
OPT Questions
James,
Not much progress for the time being as I've been on holidays for the last two weeks. I'm also starting a new job this week so might not be able to give this project as much time as I'd like for the next while.
In the mean time, can anyone give me a clue about connecting two OPT's in series/parallel?
If I series the 5KOhm inputs and parallel the 8Ohm outputs, this should give a 10kOhm load with an 8Ohm speaker, right?
If I use the 16Ohm output taps in parallel, this should show a 5kOhm load with the same speaker.
Am I on the right track here?
Thanks all,
DerFly
James,
Not much progress for the time being as I've been on holidays for the last two weeks. I'm also starting a new job this week so might not be able to give this project as much time as I'd like for the next while.
In the mean time, can anyone give me a clue about connecting two OPT's in series/parallel?
If I series the 5KOhm inputs and parallel the 8Ohm outputs, this should give a 10kOhm load with an 8Ohm speaker, right?
If I use the 16Ohm output taps in parallel, this should show a 5kOhm load with the same speaker.
Am I on the right track here?
Thanks all,
DerFly
Double
Well, not too much more progress on monoblock number one but I thought I'd spare myself some aggravation later on by starting on number two.
At least that way I caan build both in small steps at the same time. I don't actually know if this is a good or a bad thing.
So here we have it. The second chassis is almost (er, at least most of the drilling is done) finished. This is a good thing as I'm pretty much sick of drill swarf and filings by now.
Well, not too much more progress on monoblock number one but I thought I'd spare myself some aggravation later on by starting on number two.
At least that way I caan build both in small steps at the same time. I don't actually know if this is a good or a bad thing.
So here we have it. The second chassis is almost (er, at least most of the drilling is done) finished. This is a good thing as I'm pretty much sick of drill swarf and filings by now.
Attachments
Woodwork
Not much done lately although I've managed get both monoblocks up to the same stage. PS is finished on both as is all drilling and mounting of above chassis components.
Final wiring is now imminent so I've also glued a few sticks together for a chassis base.
Pots, inputs, outputs and power plugs not yet fitted. Getting there though .......
Not much done lately although I've managed get both monoblocks up to the same stage. PS is finished on both as is all drilling and mounting of above chassis components.
Final wiring is now imminent so I've also glued a few sticks together for a chassis base.
Pots, inputs, outputs and power plugs not yet fitted. Getting there though .......
Attachments
... and back
with power, input and outputs.
I've read that the input jack is a good point for the star ground to reduce hum. As in this case the input jack is not physically attached to the chassis, I see two possibilities:
1. Ground the input jack to a common star ground.
2. Use the input jack as the star ground and connect this to the chassis.
The first seems more plausible to me with my limited knowledge.
with power, input and outputs.
I've read that the input jack is a good point for the star ground to reduce hum. As in this case the input jack is not physically attached to the chassis, I see two possibilities:
1. Ground the input jack to a common star ground.
2. Use the input jack as the star ground and connect this to the chassis.
The first seems more plausible to me with my limited knowledge.
Attachments
Hello,
I have built the same version of the STC that you are, magic diode and all. I skipped the one in the B+ and frankly I don’t hear any difference when I jump the one in the screen so I left it in. All in all it is a very good sounding little amp. I have a closet full and a good friend prefers this one to my high zoot 300B SET.
I would start with just one output transformer I will try to link another STC site that shows the two transformer set up. Note that he is using 7k primaries, if you have 5K I would start with the 16 ohm taps in series. But do try the 8’s Note that the phasing of the transformers is important. Connecting one of the windings backwards probably won’t work so well…John
http://www.atatan.com/~s-ito/amp/yakinori.html
I have built the same version of the STC that you are, magic diode and all. I skipped the one in the B+ and frankly I don’t hear any difference when I jump the one in the screen so I left it in. All in all it is a very good sounding little amp. I have a closet full and a good friend prefers this one to my high zoot 300B SET.
I would start with just one output transformer I will try to link another STC site that shows the two transformer set up. Note that he is using 7k primaries, if you have 5K I would start with the 16 ohm taps in series. But do try the 8’s Note that the phasing of the transformers is important. Connecting one of the windings backwards probably won’t work so well…John
http://www.atatan.com/~s-ito/amp/yakinori.html
2wo,
Thanks for your rceommendations on the OT wiring.
Unfortunately this project has kind of stalled for a while, too much other stuff (life in general) has gotten in the way.
All the hard work is done, just need to solder in the last components. Holidays coming up soon, fingers crossed, a bit of time to finish this.........
Thanks for your rceommendations on the OT wiring.
Unfortunately this project has kind of stalled for a while, too much other stuff (life in general) has gotten in the way.
All the hard work is done, just need to solder in the last components. Holidays coming up soon, fingers crossed, a bit of time to finish this.........
I made the STC design with 2SK30 fet / 12au7 / el84 in push pull and at the front a splittertransformer from Lundahl. Superb sound with 50 year old OPT of good quality.
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