i think it's been a little weak. so i'm thinking of running a J-fet boz as a dedicaded preamp. i also noticed, as others did, that the powerlevels with 250ohm or 32 ohm are allmost the same. that makes no sense. a couple of cheep 32 ohm headphones should be blown to Kingdom amp before the pot hit the 9 o`clock point.
i also tried to run it thru spencer's take on D1 (FDA2). the sound was something in another League. But still not close as loud as it should be. that DAC combinined with a j-fet boz should do it
i also tried to run it thru spencer's take on D1 (FDA2). the sound was something in another League. But still not close as loud as it should be. that DAC combinined with a j-fet boz should do it
Going back to the switch, I hope the advice you got from the seller was correct: the language barrier can be a problem. I have a chrome/blue one which in all other respects looks identical. Under a magnifying glass the led contacts are marked + and - , and the engraving on the bezel says: 3A 240V - 12V B, which I take to mean that the led requires 12V DC.
Obviously it may come in many different flavours, but just as well to check the tiny print when it arrives.
Obviously it may come in many different flavours, but just as well to check the tiny print when it arrives.
i think it's been a little weak. so i'm thinking of running a J-fet boz as a dedicaded preamp. i also noticed, as others did, that the powerlevels with 250ohm or 32 ohm are allmost the same. that makes no sense. a couple of cheep 32 ohm headphones should be blown to Kingdom amp before the pot hit the 9 o`clock point.
i also tried to run it thru spencer's take on D1 (FDA2). the sound was something in another League. But still not close as loud as it should be. that DAC combinined with a j-fet boz should do it
You can increase the gain on the WHAMMY if you want but I prefer volume knobs all the way up if you can.
Great idea! When you say "flat bit", which one did you use? A basic spade bit? Forstner bit?
My ali seller for the case hasn't even shipped yet, but Chinese New Year is just ending, so I hope they will start shipping soon. All my Mouser, diyAudioStore, Markertek, and Digi-Key parts just arrived in time for a three day weekend
Last edited:
i think it's been a little weak. so i'm thinking of running a J-fet boz as a dedicaded preamp. i also noticed, as others did, that the powerlevels with 250ohm or 32 ohm are allmost the same. that makes no sense. a couple of cheep 32 ohm headphones should be blown to Kingdom amp before the pot hit the 9 o`clock point.
i also tried to run it thru spencer's take on D1 (FDA2). the sound was something in another League. But still not close as loud as it should be. that DAC combinined with a j-fet boz should do it
I find with the utopia (80 ohm) I never listen with the volume past 9:00. I was wondering what one would need to do to reduce the gain?
Heck, it would even be great to have a high/low gain switch.
Wait, looking at the schematic, would I change R16, 22, 29, and 32 to 15ohm or 22ohm to reduce gain?
Starting my Whammy
I'm putting in an order to Mouser,, based on the list on the opening post. A few questions:
Are there any important changes to that list since you've all been building this amp?
What transformer would you recommend from Mouser? Digikey has one that was specified in the opening post, but I'd like to save shipping!
I don't see the RCA, on/off switch, or AC plug/fuse parts specified. Can anyone point me in the right direction?
I'll run this from my preamp and would like to do without the volume pot. What changes do I need to make for this?
Very excited!
Andrew
I'm putting in an order to Mouser,, based on the list on the opening post. A few questions:
Are there any important changes to that list since you've all been building this amp?
What transformer would you recommend from Mouser? Digikey has one that was specified in the opening post, but I'd like to save shipping!
I don't see the RCA, on/off switch, or AC plug/fuse parts specified. Can anyone point me in the right direction?
I'll run this from my preamp and would like to do without the volume pot. What changes do I need to make for this?
Very excited!
Andrew
1) Nope. Works great!
2) Mouser doesn't stock a drop-in transformer for this project
3)AC jack and switching depends on your chassis and the layout. What are you using?
3.1) RCA jack - NYS367-0 REAN / Neutrik | Mouser
4) Use the pot
2) Mouser doesn't stock a drop-in transformer for this project
3)AC jack and switching depends on your chassis and the layout. What are you using?
3.1) RCA jack - NYS367-0 REAN / Neutrik | Mouser
4) Use the pot
1) Great!
2) Not great.
3) Found one! I'm using the Hammond case. Will that be big enough in case I move up to Mundorf caps and the Burson opamp?
3.1) Thanks!
4) Really? I want to save the $$ and don't see the need for it.
New question: I'm reading through these posts (116 pages!!) and 15V seems maybe a better transformer rating. Anyone have a link to the part? Any changes if I do that?
Thanks!
2) Not great.
3) Found one! I'm using the Hammond case. Will that be big enough in case I move up to Mundorf caps and the Burson opamp?
3.1) Thanks!
4) Really? I want to save the $$ and don't see the need for it.
New question: I'm reading through these posts (116 pages!!) and 15V seems maybe a better transformer rating. Anyone have a link to the part? Any changes if I do that?
Thanks!
Last edited:
15v transformer
70063K Talema Group LLC | Transformers | DigiKey
If you're wanting to use the burson opamp the biggest trick is to use a physically much smaller capacitor for the 3 of them near the socket, the suggested voltage rating and value was chosen because Nelson likes to buy by the pallet load, not that much of an exaggeration, and there's a ton of them on the shelf at Pass Labs. It's so ridiculously big for the job in those positions that you could easily use 1/10th the value and be fine. (With 25v voltage rating...)
So, get these and use near the socket UMW1E101MDD Nichicon | Capacitors | DigiKey
Sonically, my preference in this circuit is the $1 LM833. Try the Burson though. As for enormous and expensive caps fitting , there are many different sizes, so I can't address that specifically.
If you don't want to use the pot just be careful not to overdrive the whammy.
70063K Talema Group LLC | Transformers | DigiKey
If you're wanting to use the burson opamp the biggest trick is to use a physically much smaller capacitor for the 3 of them near the socket, the suggested voltage rating and value was chosen because Nelson likes to buy by the pallet load, not that much of an exaggeration, and there's a ton of them on the shelf at Pass Labs. It's so ridiculously big for the job in those positions that you could easily use 1/10th the value and be fine. (With 25v voltage rating...)
So, get these and use near the socket UMW1E101MDD Nichicon | Capacitors | DigiKey
Sonically, my preference in this circuit is the $1 LM833. Try the Burson though. As for enormous and expensive caps fitting , there are many different sizes, so I can't address that specifically.
If you don't want to use the pot just be careful not to overdrive the whammy.
Okay, so, just to be clear (newbie here):
- 15V Talema will work fine w/ no other changes necessary.
- I'll keep with the LM833. Should I still lower the caps around it? Do you mean the C3, C4...and...I don't see the third. would 100UF 25V be better anyway? Can you explain to a noob what these do and why smaller is better?
Would I want to put a resister where the pot went? How? I saw something about doing that. If so, what value?
- 15V Talema will work fine w/ no other changes necessary.
- I'll keep with the LM833. Should I still lower the caps around it? Do you mean the C3, C4...and...I don't see the third. would 100UF 25V be better anyway? Can you explain to a noob what these do and why smaller is better?
Would I want to put a resister where the pot went? How? I saw something about doing that. If so, what value?
Correct, no changes with 15V transformer.
The change in the caps around the socket is because the recommended ones are physically enormous, as well as overkill for their job. They can be electrically smaller with no change in performance, and that means you can use a physically smaller cap.
If you want to try a discrete opamp like the Burson, you'll need to make the 2 flanking the socket physically smaller, and maybe even lay them down out of the way.
If no pot you'll need to jumper (not resistors) the pads so the signal makes it to the coupling caps.
The change in the caps around the socket is because the recommended ones are physically enormous, as well as overkill for their job. They can be electrically smaller with no change in performance, and that means you can use a physically smaller cap.
If you want to try a discrete opamp like the Burson, you'll need to make the 2 flanking the socket physically smaller, and maybe even lay them down out of the way.
If no pot you'll need to jumper (not resistors) the pads so the signal makes it to the coupling caps.
Ah, physically smaller. Got it. I'll leave that for later fun.
So I put a jumper from R39/40 to the 1 uF cap. Also, I just saw the comment in the schematic that said I could vary the R39/40 resister to vary gain, which I guess is what the pot would be doing. I may be learning.
But the ground that went to the pot goes empty, yes?
Time to buy stuff!
So I put a jumper from R39/40 to the 1 uF cap. Also, I just saw the comment in the schematic that said I could vary the R39/40 resister to vary gain, which I guess is what the pot would be doing. I may be learning.
But the ground that went to the pot goes empty, yes?
Time to buy stuff!