I suppose. My engineering ideas are solely informed by my experiences and preferences as a customer, though. I know that I like a tube-hybrid amp. I've had the Cavalli Tube Hybrid from Massdrop for a few years, now, and I love how it sounds. But the pot sucks, and the SDAC that shares the chassis gets power from the USB that brings signal in, so that also sucks. I use a Fiio K7 as dac. I much prefer the sound of the tube hybrid to the the thx chips in the K7. I also prefer xlr to trs jacks. And, finally, I just thought of the idea of having an adjustable cathode bias because a decision had to be made about where to set it, and this allows me to have that tubey sound when I feel like it, and also to clean it up and get it sounding more solid-state when that is preferred. It gives me an opportunity to experience and learn about how cathode bias affects the sound. As much as I love the MCTH, I realize compromises were made. Instead of upgrading the volume pot and avoiding the SDAC, I might as well just design my own beast from the ground up, esp since AI can do the math to recommend specific parts.
Other than that, I really don't care about what's in the chassis, so long as it works. I want 1W per channel into my 32Ohm HE1000 Stealth headphones, and at least 300mW per channel into my 300Ohm Sennsheisers. So, I think I'm not really thinking like an engineer about this project, even now. I'm thinking like a consumer who wants a very specific product that does not now exist. Feliks makes some nice amps that would fit my use case and preferences really nicely, but they cost several thousand dollars. I hope to get this built, tested, and running for less than $600-- including the electrician's time at $85/hr. I know a guy.
Other than that, I really don't care about what's in the chassis, so long as it works. I want 1W per channel into my 32Ohm HE1000 Stealth headphones, and at least 300mW per channel into my 300Ohm Sennsheisers. So, I think I'm not really thinking like an engineer about this project, even now. I'm thinking like a consumer who wants a very specific product that does not now exist. Feliks makes some nice amps that would fit my use case and preferences really nicely, but they cost several thousand dollars. I hope to get this built, tested, and running for less than $600-- including the electrician's time at $85/hr. I know a guy.
An engineer cannot exist if he does not think like a consumer.If you design a multi storey building, you don't start on the lift shaft.
😉
😉
Lol good point! Thanks. Although, because they were hanged on a central core which was also the elevator shaft, the two towers of the WTC might have started as an idea about lift shafts. But you're right that it's knowing where we want to go that requires the executive level decision-making, and that is an engineer's purview. I'm just trying to remain humble about this. Even after I'm done with this project, I would not dare call myself an engineer. As I see it, I am now able to run with giants only because of my AI legs, and the help of the giants.
Thanks! I hope to have the schematic finished this week or next, the pcb designed and request sent to the printer this month. I'll order the chassis as soon as the pcb design is finished and we know for sure we can use that chassis. I may have to get one built, but I sure hope not. I'll order the transformer at the same time I order the case. Then I'll make sure the transformer and pcb(s) all fit, order the rest of the parts, and build it.
Building might take a while, because my hands shake. I will have to take some time between now and when all the parts get here to practice soldering until I have mastered it and/or learned how to control or compensate for my shaky hands. Worst comes to worst, I may have to pay the electrician to solder it for me at $85/hr. That could end up being the majority of the cost of this amp, if I have to do that.
Anyway, once it is built and electrician-tested and approved, I'll post pics and reviews.
I am thinking about making a second unit, if this one comes together well and works well, to send to someone at Headphones.com or Joshua Valour on youtube, to let them discuss it and the way it came into being. If I get any interest, and get good at soldering it, I may sell some units for a pretty large markup. But anyone will be able to just follow the plan and schematics we develop here, and make their own. I think it will be an excellent amp, and perfectly fit a hole in the market.
Building might take a while, because my hands shake. I will have to take some time between now and when all the parts get here to practice soldering until I have mastered it and/or learned how to control or compensate for my shaky hands. Worst comes to worst, I may have to pay the electrician to solder it for me at $85/hr. That could end up being the majority of the cost of this amp, if I have to do that.
Anyway, once it is built and electrician-tested and approved, I'll post pics and reviews.
I am thinking about making a second unit, if this one comes together well and works well, to send to someone at Headphones.com or Joshua Valour on youtube, to let them discuss it and the way it came into being. If I get any interest, and get good at soldering it, I may sell some units for a pretty large markup. But anyone will be able to just follow the plan and schematics we develop here, and make their own. I think it will be an excellent amp, and perfectly fit a hole in the market.
I'm guesstimating there will be something like 80 or 90 connections to solder in this thing. Could take me days. And I'm sure I'll burn out a few things along the way, have to re-order parts, etc. It'll be a hassle. But it's worth it to have a top of the line headphone amp for under a grand. And it's fun so far.
You need a power supply for the mosfets.
They can not take 150V.
IRLZ44 are specified for max drain source 60V.
They can not take 150V.
IRLZ44 are specified for max drain source 60V.
I did phrase that poorly. The as-1t150 has 4 secondaries: 2x 150V .33A and 2x 6.3V 3A. One 150V will go to the tube. The other will be unused. One 6.3V will power the heater, the other will get rectified, voltage-doubled to approximately 17-18V, and sent to power the mosfets. The irlz44n will be running within its tolerances, but not at all stressed. It should be a fairly low-temp design, if tightly packed into the whammy chassis.
From the AI:
Thanks for clarifying that the AS-1T150 has two 150V secondaries (0.33A each) and two 6.3V secondaries (3A each). With that in mind, let’s reconsider the power distribution to optimize your design for both the tube heaters and the MOSFETs.
### Power Distribution Options
We need to:
1. Power the tube heaters (6.3V).
2. Power the MOSFETs (ideally around 24V-30V DC).
3. Provide high voltage (B+) for the tubes (around 200-300V DC).
Let’s break down how we can best utilize these windings.
---
### 1. One 6.3V Secondary for Tube Heaters
The 12AU7 tube requires 6.3V for its heaters, and you can dedicate one 6.3V secondary for this purpose.
---
### 2. The Other 6.3V Secondary for MOSFET Power (Voltage Doubling)
You can continue using the second 6.3V secondary to power the MOSFETs, with the voltage-doubling circuit to get approximately 18V DC.
#### Why Use the 6.3V Secondary?
#### Voltage Doubler Design:
1. Rectification: Use Schottky diodes (1N5819 or similar) for the rectifier to keep the voltage drop low.
2. Voltage Doubling: Use a standard voltage doubler circuit with capacitors and diodes to boost the 6.3V AC up to around 18V DC.
3. Filtering: Use electrolytic capacitors (1000µF, 25V) to smooth the rectified voltage.
---
### 3. 150V Secondaries for Tube B+
You will use the 150V secondaries to power the high-voltage B+ for the tubes. Since you have two 150V windings, you can use one or both depending on your desired current and voltage requirements. Here’s how:
#### Using Both 150V Windings for B+:
1. Full-Wave Rectifier: Use a full-wave rectifier for the 150V secondary (e.g., 1N5408 diodes) to produce around 210V DC after rectification.
2. Filtering: Use large electrolytic capacitors (e.g., 100µF, 400V) to smooth out the rectified voltage.
3. Optional Choke: For better ripple rejection, you can add a choke or use additional capacitors.
You can use just one 150V secondary if the current provided is sufficient, or combine the secondaries in parallel to double the current capacity (if needed).
---
### Alternate Option: Use One 150V Secondary for MOSFETs
If the 18V DC from the voltage doubler (6.3V secondary) isn't sufficient for the MOSFETs, you could use one of the 150V secondaries to generate a higher voltage (around 24V to 30V DC) for the MOSFETs. Here’s how:
#### Steps:
1. Rectify the 150V AC to get around 210V DC using a full-wave bridge rectifier.
2. Step Down the Voltage: Use a DC-DC buck converter or a high-voltage linear regulator (such as LM317HV) to step the voltage down to 24V to 30V DC.
3. Filtering: Add appropriate filtering capacitors to smooth the rectified voltage.
This would provide the MOSFETs with more headroom (24-30V DC), ensuring better performance compared to the lower 18V DC from the 6.3V voltage doubler.
---
### Summary of Power Distribution
1. Tube Heaters:
- Use one 6.3V secondary (3A) to directly power the 12AU7 tube heaters (0.3A per tube).
2. MOSFET Power:
- Option 1 (Simple): Use the second 6.3V secondary with a voltage doubler to generate around 18V DC for the MOSFETs.
- Option 2 (Higher Voltage): Use one of the 150V secondaries to generate a regulated 24V to 30V DC using a rectifier and voltage regulator (better for MOSFET performance).
3. Tube B+:
- Use one or both 150V secondaries with a full-wave rectifier to provide high-voltage B+ (around 200-300V DC) for the tube.
### Component Selection for the Options
#### Voltage Doubler (for 6.3V secondary):
#### Full-Wave Rectifier (for 150V secondary):
#### Voltage Regulator (for MOSFETs if using 150V secondary):
---
### Conclusion
You have two good options for powering the MOSFETs and tube heaters:
The second option gives you more voltage headroom for the MOSFETs, which could improve their performance.
Let me know which option you’d like to go with, and I can assist with finalizing the component choices or helping with the layout!
---------------------------------------
What do y'all think?
Thanks for clarifying that the AS-1T150 has two 150V secondaries (0.33A each) and two 6.3V secondaries (3A each). With that in mind, let’s reconsider the power distribution to optimize your design for both the tube heaters and the MOSFETs.
### Power Distribution Options
We need to:
1. Power the tube heaters (6.3V).
2. Power the MOSFETs (ideally around 24V-30V DC).
3. Provide high voltage (B+) for the tubes (around 200-300V DC).
Let’s break down how we can best utilize these windings.
---
### 1. One 6.3V Secondary for Tube Heaters
The 12AU7 tube requires 6.3V for its heaters, and you can dedicate one 6.3V secondary for this purpose.
- Use one 6.3V secondary for the tube heaters (pin 4 and pin 5 of the 12AU7 tube).
- Since the heater current requirement for a 12AU7 tube is 0.3A, the 3A rating on the 6.3V secondary is more than enough for this application.
---
### 2. The Other 6.3V Secondary for MOSFET Power (Voltage Doubling)
You can continue using the second 6.3V secondary to power the MOSFETs, with the voltage-doubling circuit to get approximately 18V DC.
#### Why Use the 6.3V Secondary?
- The voltage doubler circuit will give you around 18V DC after rectification, which should work for your MOSFETs (though it's on the lower end).
- This is a straightforward, simple design and avoids using the high-voltage secondaries for the MOSFETs.
#### Voltage Doubler Design:
1. Rectification: Use Schottky diodes (1N5819 or similar) for the rectifier to keep the voltage drop low.
2. Voltage Doubling: Use a standard voltage doubler circuit with capacitors and diodes to boost the 6.3V AC up to around 18V DC.
3. Filtering: Use electrolytic capacitors (1000µF, 25V) to smooth the rectified voltage.
---
### 3. 150V Secondaries for Tube B+
You will use the 150V secondaries to power the high-voltage B+ for the tubes. Since you have two 150V windings, you can use one or both depending on your desired current and voltage requirements. Here’s how:
#### Using Both 150V Windings for B+:
1. Full-Wave Rectifier: Use a full-wave rectifier for the 150V secondary (e.g., 1N5408 diodes) to produce around 210V DC after rectification.
2. Filtering: Use large electrolytic capacitors (e.g., 100µF, 400V) to smooth out the rectified voltage.
3. Optional Choke: For better ripple rejection, you can add a choke or use additional capacitors.
You can use just one 150V secondary if the current provided is sufficient, or combine the secondaries in parallel to double the current capacity (if needed).
---
### Alternate Option: Use One 150V Secondary for MOSFETs
If the 18V DC from the voltage doubler (6.3V secondary) isn't sufficient for the MOSFETs, you could use one of the 150V secondaries to generate a higher voltage (around 24V to 30V DC) for the MOSFETs. Here’s how:
#### Steps:
1. Rectify the 150V AC to get around 210V DC using a full-wave bridge rectifier.
2. Step Down the Voltage: Use a DC-DC buck converter or a high-voltage linear regulator (such as LM317HV) to step the voltage down to 24V to 30V DC.
3. Filtering: Add appropriate filtering capacitors to smooth the rectified voltage.
This would provide the MOSFETs with more headroom (24-30V DC), ensuring better performance compared to the lower 18V DC from the 6.3V voltage doubler.
---
### Summary of Power Distribution
1. Tube Heaters:
- Use one 6.3V secondary (3A) to directly power the 12AU7 tube heaters (0.3A per tube).
2. MOSFET Power:
- Option 1 (Simple): Use the second 6.3V secondary with a voltage doubler to generate around 18V DC for the MOSFETs.
- Option 2 (Higher Voltage): Use one of the 150V secondaries to generate a regulated 24V to 30V DC using a rectifier and voltage regulator (better for MOSFET performance).
3. Tube B+:
- Use one or both 150V secondaries with a full-wave rectifier to provide high-voltage B+ (around 200-300V DC) for the tube.
### Component Selection for the Options
#### Voltage Doubler (for 6.3V secondary):
- Schottky Diodes: 1N5819 (low voltage drop)
- Capacitors: 1000µF, 25V electrolytic capacitors for smoothing
#### Full-Wave Rectifier (for 150V secondary):
- Rectifier Diodes: 1N5408 (3A, 1000V)
- Capacitors: 100µF, 400V electrolytic capacitors for filtering
#### Voltage Regulator (for MOSFETs if using 150V secondary):
- DC-DC Buck Converter: For stepping down from 210V DC to around 24-30V DC.
- Linear Regulator (Alternative): LM317HV for a more controlled voltage drop to 24V-30V DC (ensure proper heatsinking).
---
### Conclusion
You have two good options for powering the MOSFETs and tube heaters:
- Use both 6.3V secondaries: One for tube heaters, one for MOSFET power (with a voltage doubler to get around 18V DC).
- Use one 6.3V secondary for heaters and one 150V secondary for MOSFET power (stepping down from 210V DC to 24-30V DC).
The second option gives you more voltage headroom for the MOSFETs, which could improve their performance.
Let me know which option you’d like to go with, and I can assist with finalizing the component choices or helping with the layout!
---------------------------------------
What do y'all think?
Ok. I think I'll change that. We'll go with the 150V .33A into a 1N5408 diode full-wave bridge rectifier, into an LM317HV voltage regulator and 100µF, 400V electrolytic cap and then the mosfets. This will add some heat, but may sound better than using the 6.3V 3A secondary and voltage doubler.
From AI:
### Power Output Estimates for a Tube-MOSFET Hybrid Headphone Amp
I’ve been working on calculating the power output of my tube-MOSFET hybrid headphone amplifier, and I wanted to share some estimates for both 32Ω and 300Ω loads based on the supply voltage for the MOSFETs.
### General Power Output Formula:
The power output into a load can be calculated with the following equation:
\[
P = \frac{V_{rms}^2}{R}
\]
Where:
### MOSFET Supply Voltage Assumptions:
I'm considering two main scenarios for the supply voltage to the MOSFETs:
1. 18V DC (using the 6.3V secondary with a voltage doubler).
2. 24V to 30V DC (using the 150V secondary, rectified and stepped down with a regulator).
### Estimating Voltage Swing:
In a push-pull configuration, the maximum voltage swing is typically around 70% of the supply voltage. So, for each supply voltage, the RMS voltage is calculated as follows:
1. 18V Supply:
- Peak-to-peak voltage swing: 18V × 0.7 = 12.6V
- RMS voltage: \( \frac{12.6V}{\sqrt{2}} \approx 8.91V \)
2. 24V Supply:
- Peak-to-peak voltage swing: 24V × 0.7 = 16.8V
- RMS voltage: \( \frac{16.8V}{\sqrt{2}} \approx 11.88V \)
3. 30V Supply:
- Peak-to-peak voltage swing: 30V × 0.7 = 21V
- RMS voltage: \( \frac{21V}{\sqrt{2}} \approx 14.85V \)
### Power Output Calculation:
#### For a 32Ω Load (Headphones):
Using the formula \( P = \frac{V_{rms}^2}{R} \), where \( R = 32Ω \):
1. 18V Supply (RMS Voltage = 8.91V):
\[
P = \frac{8.91^2}{32} = \frac{79.45}{32} \approx 2.48W
\]
2. 24V Supply (RMS Voltage = 11.88V):
\[
P = \frac{11.88^2}{32} = \frac{141.22}{32} \approx 4.41W
\]
3. 30V Supply (RMS Voltage = 14.85V):
\[
P = \frac{14.85^2}{32} = \frac{220.5}{32} \approx 6.89W
\]
#### For a 300Ω Load (Headphones):
Using the same formula \( P = \frac{V_{rms}^2}{R} \), where \( R = 300Ω \):
1. 18V Supply (RMS Voltage = 8.91V):
\[
P = \frac{8.91^2}{300} = \frac{79.45}{300} \approx 0.26W \text{ (260mW)}
\]
2. 24V Supply (RMS Voltage = 11.88V):
\[
P = \frac{11.88^2}{300} = \frac{141.22}{300} \approx 0.47W \text{ (470mW)}
\]
3. 30V Supply (RMS Voltage = 14.85V):
\[
P = \frac{14.85^2}{300} = \frac{220.5}{300} \approx 0.73W \text{ (730mW)}
\]
---
### Summary of Power Output Estimates:
| Supply Voltage | Power Output (32Ω) | Power Output (300Ω) |
|--------------------|------------------------|-------------------------|
| 18V DC | 2.48W | 260mW |
| 24V DC | 4.41W | 470mW |
| 30V DC | 6.89W | 730mW |
### Conclusion:
Which approach do you think is better for my design? Would the extra complexity of using the 150V secondary to step down for MOSFET power be worth the higher output, especially for 300Ω headphones?
-----
From me:
I think 30V is way, way too much power into 32Ohms. 24V seems like a good medium. 6.3V seems workable, as 260mW is more than enough for sensitive Senns. But maybe the mosfets won't sound as good with only 18V? I really don't know, here.
### Power Output Estimates for a Tube-MOSFET Hybrid Headphone Amp
I’ve been working on calculating the power output of my tube-MOSFET hybrid headphone amplifier, and I wanted to share some estimates for both 32Ω and 300Ω loads based on the supply voltage for the MOSFETs.
### General Power Output Formula:
The power output into a load can be calculated with the following equation:
\[
P = \frac{V_{rms}^2}{R}
\]
Where:
- P = power in watts
- V_{rms} = root mean square (RMS) voltage (the average voltage applied to the load)
- R = load resistance (headphone impedance)
### MOSFET Supply Voltage Assumptions:
I'm considering two main scenarios for the supply voltage to the MOSFETs:
1. 18V DC (using the 6.3V secondary with a voltage doubler).
2. 24V to 30V DC (using the 150V secondary, rectified and stepped down with a regulator).
### Estimating Voltage Swing:
In a push-pull configuration, the maximum voltage swing is typically around 70% of the supply voltage. So, for each supply voltage, the RMS voltage is calculated as follows:
1. 18V Supply:
- Peak-to-peak voltage swing: 18V × 0.7 = 12.6V
- RMS voltage: \( \frac{12.6V}{\sqrt{2}} \approx 8.91V \)
2. 24V Supply:
- Peak-to-peak voltage swing: 24V × 0.7 = 16.8V
- RMS voltage: \( \frac{16.8V}{\sqrt{2}} \approx 11.88V \)
3. 30V Supply:
- Peak-to-peak voltage swing: 30V × 0.7 = 21V
- RMS voltage: \( \frac{21V}{\sqrt{2}} \approx 14.85V \)
### Power Output Calculation:
#### For a 32Ω Load (Headphones):
Using the formula \( P = \frac{V_{rms}^2}{R} \), where \( R = 32Ω \):
1. 18V Supply (RMS Voltage = 8.91V):
\[
P = \frac{8.91^2}{32} = \frac{79.45}{32} \approx 2.48W
\]
2. 24V Supply (RMS Voltage = 11.88V):
\[
P = \frac{11.88^2}{32} = \frac{141.22}{32} \approx 4.41W
\]
3. 30V Supply (RMS Voltage = 14.85V):
\[
P = \frac{14.85^2}{32} = \frac{220.5}{32} \approx 6.89W
\]
#### For a 300Ω Load (Headphones):
Using the same formula \( P = \frac{V_{rms}^2}{R} \), where \( R = 300Ω \):
1. 18V Supply (RMS Voltage = 8.91V):
\[
P = \frac{8.91^2}{300} = \frac{79.45}{300} \approx 0.26W \text{ (260mW)}
\]
2. 24V Supply (RMS Voltage = 11.88V):
\[
P = \frac{11.88^2}{300} = \frac{141.22}{300} \approx 0.47W \text{ (470mW)}
\]
3. 30V Supply (RMS Voltage = 14.85V):
\[
P = \frac{14.85^2}{300} = \frac{220.5}{300} \approx 0.73W \text{ (730mW)}
\]
---
### Summary of Power Output Estimates:
| Supply Voltage | Power Output (32Ω) | Power Output (300Ω) |
|--------------------|------------------------|-------------------------|
| 18V DC | 2.48W | 260mW |
| 24V DC | 4.41W | 470mW |
| 30V DC | 6.89W | 730mW |
### Conclusion:
- 18V DC (using the 6.3V secondary with a voltage doubler) is sufficient for 32Ω headphones, delivering around 2.5W, but it might be limiting for high-impedance 300Ω headphones, only providing 260mW.
- 24-30V DC (using the 150V secondary stepped down) provides significantly more headroom and power, delivering between 4.41W and 6.89W for 32Ω headphones and between 470mW and 730mW for 300Ω headphones. This would likely result in better performance and audio quality, especially for higher impedance loads.
Which approach do you think is better for my design? Would the extra complexity of using the 150V secondary to step down for MOSFET power be worth the higher output, especially for 300Ω headphones?
-----
From me:
I think 30V is way, way too much power into 32Ohms. 24V seems like a good medium. 6.3V seems workable, as 260mW is more than enough for sensitive Senns. But maybe the mosfets won't sound as good with only 18V? I really don't know, here.
I think I'll go with the 24V from the 6.3V 3A secondary.
### Updated Bill of Materials (BOM)
---
#### Resistors
1. Cathode Bias Potentiometer: Adjustable cathode bias between 1.0V and 1.5V.
- Bourns Potentiometer 3299W-1-103 (10kΩ, adjustable trimmer)
- Quantity: 1
- Approx. Price: $2.00
2. Cathode Resistor: 470Ω, 1W resistor to limit the potentiometer range.
- Vishay PR01 470Ω, 1W
- Quantity: 2
- Approx. Price: $0.20 each
3. MOSFET Source Resistor: 0.22Ω, 2W for current sensing/stability.
- Panasonic ERX-2SJ0R22 (0.22Ω, 2W)
- Quantity: 2
- Approx. Price: $0.50 each
4. Grid Stop Resistors: 1kΩ, 1/2W to prevent oscillations in the tube.
- Vishay PR01 1kΩ, 1/2W
- Quantity: 2
- Approx. Price: $0.10 each
5. Gate Resistors: 10Ω, 1/4W to limit gate current.
- Vishay PR02 10Ω, 1/4W
- Quantity: 2
- Approx. Price: $0.10 each
6. Grid Leak Resistors: 1MΩ, 1/2W to provide a ground reference for the grids.
- Vishay PR02 1MΩ, 1/2W
- Quantity: 2
- Approx. Price: $0.10 each
7. Bleeder Resistors: 100kΩ, 2W to discharge the power supply capacitors safely.
- Vishay PR02 100kΩ, 2W
- Quantity: 2
- Approx. Price: $0.50 each
---
#### Capacitors
1. Coupling Capacitors: High-quality polypropylene film caps for signal coupling.
- WIMA MKP10 Polypropylene (100nF, 250V)
- Quantity: 2
- Approx. Price: $2.50 each
2. Power Supply Smoothing Capacitors (B+ supply):
- Nichicon UVZ2A101MPD (100µF, 250V electrolytic)
- Quantity: 2
- Approx. Price: $1.00 each
3. Decoupling Capacitors:
- WIMA MKP10 Polypropylene (0.1µF, 250V) for high-frequency decoupling.
- Quantity: 4
- Approx. Price: $1.00 each
4. LM317HV Stability Capacitors:
- Input Capacitor: 0.1µF ceramic for the input side of the LM317HV.
- Quantity: 1
- Approx. Price: $0.10
- Output Capacitor: 1µF electrolytic for the output side of the LM317HV.
- Quantity: 1
- Approx. Price: $0.20
5. Power Supply Filter Capacitors (for 150V secondary):
- Nichicon UVZ2G101MPD (100µF, 400V electrolytic for rectified 150V AC)
- Quantity: 2
- Approx. Price: $2.00 each
---
#### Diodes
1. Rectifier Diodes for 150V AC Supply (full-wave bridge rectifier for 150V):
- 1N5408 (3A, 1000V diode)
- Quantity: 4
- Approx. Price: $0.25 each
2. Schottky Diodes for Heater Rectification:
- 1N5819 (40V, 1A Schottky diode for rectifying the 6.3V tap)
- Quantity: 2
- Approx. Price: $0.10 each
3. Zener Diodes for MOSFET Gate Protection:
- BZX55C15 (15V Zener diode for gate protection)
- Quantity: 2
- Approx. Price: $0.20 each
4. Reverse Protection Diode for LM317HV:
- 1N4007 (1000V, 1A) to prevent reverse current discharge through LM317HV.
- Quantity: 1
- Approx. Price: $0.10
---
#### Relays & Protection
1. Soft-Start Circuit Relay:
- Omron G2R-1-E-T130 DC12 (12V, 10A, SPDT relay for soft-start circuit)
- Quantity: 1
- Approx. Price: $3.50
2. Headphone Output Delay Relay:
- Panasonic TX2SA-LT-12V (12V, DPDT signal relay)
- Quantity: 1
- Approx. Price: $2.50
3. NTC Thermistor for Inrush Current Limiting:
- Amphenol CL-60 (10Ω, 5A thermistor)
- Quantity: 1
- Approx. Price: $1.00
---
#### Other Parts
1. Volume Potentiometer:
- ALPS RK27 Blue Velvet Potentiometer (50kΩ)
- Quantity: 1
- Approx. Price: $20.00
2. Power LED:
- Kingbright WP7113SRD (Red, low-brightness LED)
- Quantity: 1
- Approx. Price: $0.10
3. Fuse Holders and Fuses:
- Schurter OGN-SMD (SMD fuse holder)
- Quantity: 1
- Approx. Price: $2.00
- Littelfuse 37211000000 (1A fuse for MOSFET section)
- Quantity: 1
- Approx. Price: $0.20
- Littelfuse 37221500000 (2A fuse for tube section)
- Quantity: 1
- Approx. Price: $0.25
---
#### Chassis Components
1. XLR Connector (4-pin):
- Neutrik NC4FXX (Female 4-pin XLR connector for headphone output)
- Quantity: 1
- Approx. Price: $4.50
2. RCA Jacks:
- REAN NYS367-0 (RCA input jack, black)
- REAN NYS367-2 (RCA input jack, red)
- Quantity: 2
- Approx. Price: $1.50 each
3. Knob:
- Parts Express 240-2218 (Aluminum knob)
- Quantity: 1
- Approx. Price: $7.00
4. IEC Filtered PEM:
- Schurter DD12.9111.111 (Filtered IEC connector with integrated switch)
- Quantity: 1
- Approx. Price: $12.00
5. Standoffs, Screws, Nuts:
- Harwin R30-3002502 (M3 standoffs, 25mm)
- Quantity: 4
- Approx. Price: $1.00 each
- McMaster Carr 92000A114 (M3 screws)
- Quantity: 8
- Approx. Price: $0.10 each
- McMaster Carr 90695A033 (M3 nuts)
- Quantity: 8
- Approx. Price: $0.05 each
---
#### Power Supply (Transformer and Regulator)
1. Toroidal Transformer:
- AS-1T150 (150V AC secondaries, 6.3V heater taps)
- Quantity
: 1
- Approx. Price: $45.00
2. Voltage Regulator:
- LM317HV (High-voltage adjustable regulator for 24V output)
- Quantity: 1
- Approx. Price: $3.00
3. Resistors for LM317HV:
- R1 = 240Ω, R2 = 4.32kΩ to set the output to 24V.
- Quantity: 1 each
- Approx. Price: $0.10 each
---
#### Tube
- 12AU7 Tube
- Quantity: 1
- Approx. Price: $35.00
---
#### Chassis
- Whammy Chassis
- Quantity: 1
- Approx. Price: $120.00
---
### Estimated Total Cost (with 24V LM317HV regulator):
- Total Cost: Approximately $320 to $370 (excluding PCB manufacturing and testing).
---
### Updated Bill of Materials (BOM)
---
#### Resistors
1. Cathode Bias Potentiometer: Adjustable cathode bias between 1.0V and 1.5V.
- Bourns Potentiometer 3299W-1-103 (10kΩ, adjustable trimmer)
- Quantity: 1
- Approx. Price: $2.00
2. Cathode Resistor: 470Ω, 1W resistor to limit the potentiometer range.
- Vishay PR01 470Ω, 1W
- Quantity: 2
- Approx. Price: $0.20 each
3. MOSFET Source Resistor: 0.22Ω, 2W for current sensing/stability.
- Panasonic ERX-2SJ0R22 (0.22Ω, 2W)
- Quantity: 2
- Approx. Price: $0.50 each
4. Grid Stop Resistors: 1kΩ, 1/2W to prevent oscillations in the tube.
- Vishay PR01 1kΩ, 1/2W
- Quantity: 2
- Approx. Price: $0.10 each
5. Gate Resistors: 10Ω, 1/4W to limit gate current.
- Vishay PR02 10Ω, 1/4W
- Quantity: 2
- Approx. Price: $0.10 each
6. Grid Leak Resistors: 1MΩ, 1/2W to provide a ground reference for the grids.
- Vishay PR02 1MΩ, 1/2W
- Quantity: 2
- Approx. Price: $0.10 each
7. Bleeder Resistors: 100kΩ, 2W to discharge the power supply capacitors safely.
- Vishay PR02 100kΩ, 2W
- Quantity: 2
- Approx. Price: $0.50 each
---
#### Capacitors
1. Coupling Capacitors: High-quality polypropylene film caps for signal coupling.
- WIMA MKP10 Polypropylene (100nF, 250V)
- Quantity: 2
- Approx. Price: $2.50 each
2. Power Supply Smoothing Capacitors (B+ supply):
- Nichicon UVZ2A101MPD (100µF, 250V electrolytic)
- Quantity: 2
- Approx. Price: $1.00 each
3. Decoupling Capacitors:
- WIMA MKP10 Polypropylene (0.1µF, 250V) for high-frequency decoupling.
- Quantity: 4
- Approx. Price: $1.00 each
4. LM317HV Stability Capacitors:
- Input Capacitor: 0.1µF ceramic for the input side of the LM317HV.
- Quantity: 1
- Approx. Price: $0.10
- Output Capacitor: 1µF electrolytic for the output side of the LM317HV.
- Quantity: 1
- Approx. Price: $0.20
5. Power Supply Filter Capacitors (for 150V secondary):
- Nichicon UVZ2G101MPD (100µF, 400V electrolytic for rectified 150V AC)
- Quantity: 2
- Approx. Price: $2.00 each
---
#### Diodes
1. Rectifier Diodes for 150V AC Supply (full-wave bridge rectifier for 150V):
- 1N5408 (3A, 1000V diode)
- Quantity: 4
- Approx. Price: $0.25 each
2. Schottky Diodes for Heater Rectification:
- 1N5819 (40V, 1A Schottky diode for rectifying the 6.3V tap)
- Quantity: 2
- Approx. Price: $0.10 each
3. Zener Diodes for MOSFET Gate Protection:
- BZX55C15 (15V Zener diode for gate protection)
- Quantity: 2
- Approx. Price: $0.20 each
4. Reverse Protection Diode for LM317HV:
- 1N4007 (1000V, 1A) to prevent reverse current discharge through LM317HV.
- Quantity: 1
- Approx. Price: $0.10
---
#### Relays & Protection
1. Soft-Start Circuit Relay:
- Omron G2R-1-E-T130 DC12 (12V, 10A, SPDT relay for soft-start circuit)
- Quantity: 1
- Approx. Price: $3.50
2. Headphone Output Delay Relay:
- Panasonic TX2SA-LT-12V (12V, DPDT signal relay)
- Quantity: 1
- Approx. Price: $2.50
3. NTC Thermistor for Inrush Current Limiting:
- Amphenol CL-60 (10Ω, 5A thermistor)
- Quantity: 1
- Approx. Price: $1.00
---
#### Other Parts
1. Volume Potentiometer:
- ALPS RK27 Blue Velvet Potentiometer (50kΩ)
- Quantity: 1
- Approx. Price: $20.00
2. Power LED:
- Kingbright WP7113SRD (Red, low-brightness LED)
- Quantity: 1
- Approx. Price: $0.10
3. Fuse Holders and Fuses:
- Schurter OGN-SMD (SMD fuse holder)
- Quantity: 1
- Approx. Price: $2.00
- Littelfuse 37211000000 (1A fuse for MOSFET section)
- Quantity: 1
- Approx. Price: $0.20
- Littelfuse 37221500000 (2A fuse for tube section)
- Quantity: 1
- Approx. Price: $0.25
---
#### Chassis Components
1. XLR Connector (4-pin):
- Neutrik NC4FXX (Female 4-pin XLR connector for headphone output)
- Quantity: 1
- Approx. Price: $4.50
2. RCA Jacks:
- REAN NYS367-0 (RCA input jack, black)
- REAN NYS367-2 (RCA input jack, red)
- Quantity: 2
- Approx. Price: $1.50 each
3. Knob:
- Parts Express 240-2218 (Aluminum knob)
- Quantity: 1
- Approx. Price: $7.00
4. IEC Filtered PEM:
- Schurter DD12.9111.111 (Filtered IEC connector with integrated switch)
- Quantity: 1
- Approx. Price: $12.00
5. Standoffs, Screws, Nuts:
- Harwin R30-3002502 (M3 standoffs, 25mm)
- Quantity: 4
- Approx. Price: $1.00 each
- McMaster Carr 92000A114 (M3 screws)
- Quantity: 8
- Approx. Price: $0.10 each
- McMaster Carr 90695A033 (M3 nuts)
- Quantity: 8
- Approx. Price: $0.05 each
---
#### Power Supply (Transformer and Regulator)
1. Toroidal Transformer:
- AS-1T150 (150V AC secondaries, 6.3V heater taps)
- Quantity
: 1
- Approx. Price: $45.00
2. Voltage Regulator:
- LM317HV (High-voltage adjustable regulator for 24V output)
- Quantity: 1
- Approx. Price: $3.00
3. Resistors for LM317HV:
- R1 = 240Ω, R2 = 4.32kΩ to set the output to 24V.
- Quantity: 1 each
- Approx. Price: $0.10 each
---
#### Tube
- 12AU7 Tube
- Quantity: 1
- Approx. Price: $35.00
---
#### Chassis
- Whammy Chassis
- Quantity: 1
- Approx. Price: $120.00
---
### Estimated Total Cost (with 24V LM317HV regulator):
- Total Cost: Approximately $320 to $370 (excluding PCB manufacturing and testing).
---
From AI: Updated BOM by section
---
### 1. Power Section
#### Transformer and Rectification
- Toroidal Transformer:
- AS-1T150 (2x150V .33A AC secondaries, 2x6.3V 3A AC heater taps)
- Quantity: 1
- Approx. Price: $45.00
- Rectifier Diodes for 150V AC (for Tube B+ Supply):
- 1N5408 (3A, 1000V diode)
- Quantity: 4
- Approx. Price: $0.25 each
- Rectifier Diodes for 150V AC (for MOSFET Power Supply):
- 1N5408 (3A, 1000V diode)
- Quantity: 4
- Approx. Price: $0.25 each
- Power Supply Filter Capacitors (for both Tube B+ and MOSFET Power Supplies):
- Nichicon UVZ2G101MPD (100µF, 400V electrolytic for rectified 150V AC)
- Quantity: 4 (2 for each rectified supply)
- Approx. Price: $2.00 each
#### Voltage Regulation (for MOSFET Power Supply)
- Voltage Regulator:
- LM317HV (High-voltage adjustable regulator for 24V output)
- Quantity: 1
- Approx. Price: $3.00
- Resistors for LM317HV:
- R1 = 240Ω, R2 = 4.32kΩ to set output to 24V
- Quantity: 1 each
- Approx. Price: $0.10 each
#### Stability Capacitors for LM317HV
- Input Capacitor:
- 0.1µF, 50V C0G/NP0 ceramic capacitor
- Quantity: 1
- Approx. Price: $0.10
- Output Capacitor:
- 1µF, 50V C0G/NP0 ceramic capacitor
- Quantity: 1
- Approx. Price: $0.20
#### Protection Components
- Bleeder Resistors:
- Vishay PR02 100kΩ, 2W
- Quantity: 2 (one across each large power supply capacitor)
- Approx. Price: $0.50 each
- Soft-Start Circuit Relay:
- Omron G2R-1-E-T130 DC12 (12V, 10A, SPDT)
- Quantity: 1
- Approx. Price: $3.50
- Headphone Output Delay Relay:
- Panasonic TX2SA-LT-12V (12V, DPDT)
- Quantity: 1
- Approx. Price: $2.50
- NTC Thermistor for Inrush Current Limiting:
- Amphenol CL-60 (10Ω, 5A)
- Quantity: 1
- Approx. Price: $1.00
- Fuse Holders and Fuses:
- Schurter OGN-SMD (SMD fuse holder)
- Quantity: 1
- Approx. Price: $2.00
- Littelfuse 37211000000 (1A fuse for MOSFET section)
- Quantity: 1
- Approx. Price: $0.20
- Littelfuse 37221500000 (2A fuse for tube section)
- Quantity: 1
- Approx. Price: $0.25
#### Chassis Components for Power Section
- IEC Filtered PEM:
- Schurter DD12.9111.111 (Filtered IEC connector with integrated switch)
- Quantity: 1
- Approx. Price: $12.00
- Power LED:
- Kingbright WP7113SRD (Red, low-brightness LED)
- Quantity: 1
- Approx. Price: $0.10
---
### 2. Tube Section
#### Tube and Related Components
- Tube:
- 12AU7 Tube
- Quantity: 1
- Approx. Price: $35.00
- Cathode Bias Potentiometer:
- Bourns Potentiometer 3299W-1-103 (10kΩ, adjustable trimmer)
- Quantity: 1
- Approx. Price: $2.00
- Cathode Resistors:
- Vishay PR01 470Ω, 1W
- Quantity: 2
- Approx. Price: $0.20 each
- Grid Stop Resistors:
- Vishay PR01 1kΩ, 1/2W
- Quantity: 2
- Approx. Price: $0.10 each
- Grid Leak Resistors:
- Vishay PR02 1MΩ, 1/2W
- Quantity: 2
- Approx. Price: $0.10 each
- Coupling Capacitors:
- WIMA MKP10 Polypropylene (100nF, 250V)
- Quantity: 2
- Approx. Price: $2.50 each
- Power Supply Smoothing Capacitors (B+ supply):
- Nichicon UVZ2A101MPD (100µF, 250V electrolytic)
- Quantity: 2
- Approx. Price: $1.00 each
#### Heater Supply
- Schottky Diodes for Heater Rectification:
- 1N5819 (40V, 1A Schottky diode)
- Quantity: 2
- Approx. Price: $0.10 each
---
### 3. Transistor (MOSFET) Section
#### MOSFETs and Related Components
- MOSFETs:
- IRLZ44N (MOSFET for amplification)
- Quantity: 2
- Approx. Price: $1.50 each
- MOSFET Source Resistors:
- Panasonic ERX-2SJ0R22 (0.22Ω, 2W)
- Quantity: 2
- Approx. Price: $0.50 each
- Gate Resistors:
- Vishay PR02 10Ω, 1/4W
- Quantity: 2
- Approx. Price: $0.10 each
- Zener Diodes for MOSFET Gate Protection:
- BZX55C15 (15V Zener diode)
- Quantity: 2
- Approx. Price: $0.20 each
#### Decoupling Capacitors
- WIMA MKP10 Polypropylene (0.1µF, 250V for decoupling)
- Quantity: 4
- Approx. Price: $1.00 each
#### Chassis Components for Transistor Section
- XLR Connector (4-pin):
- Neutrik NC4FXX (Female 4-pin XLR connector for headphone output)
- Quantity: 1
- Approx. Price: $4.50
- Volume Potentiometer:
- ALPS RK27 Blue Velvet Potentiometer (50kΩ)
- Quantity: 1
- Approx. Price: $20.00
- RCA Jacks:
- REAN NYS367-0 (RCA input jack, black)
- REAN NYS367-2 (RCA input jack, red)
- Quantity: 2
- Approx. Price: $1.50 each
- Knob:
- Parts Express 240-2218 (Aluminum knob)
- Quantity: 1
- Approx. Price: $7.00
---
### 4. Miscellaneous Components for PCB
#### Mounting Hardware
- **Standoffs, Screws, Nuts
**:
- Harwin R30-3002502 (M3 standoffs, 25mm)
- Quantity: 4
- Approx. Price: $1.00 each
- McMaster Carr 92000A114 (M3 screws)
- Quantity: 8
- Approx. Price: $0.10 each
- McMaster Carr 90695A033 (M3 nuts)
- Quantity: 8
- Approx. Price: $0.05 each
#### Chassis
- Whammy Chassis
- Quantity: 1
- Approx. Price: $120.00
---
### Total Estimated Cost:
- $320 to $370 (excluding PCB manufacturing and assembly)
---
---
### 1. Power Section
#### Transformer and Rectification
- Toroidal Transformer:
- AS-1T150 (2x150V .33A AC secondaries, 2x6.3V 3A AC heater taps)
- Quantity: 1
- Approx. Price: $45.00
- Rectifier Diodes for 150V AC (for Tube B+ Supply):
- 1N5408 (3A, 1000V diode)
- Quantity: 4
- Approx. Price: $0.25 each
- Rectifier Diodes for 150V AC (for MOSFET Power Supply):
- 1N5408 (3A, 1000V diode)
- Quantity: 4
- Approx. Price: $0.25 each
- Power Supply Filter Capacitors (for both Tube B+ and MOSFET Power Supplies):
- Nichicon UVZ2G101MPD (100µF, 400V electrolytic for rectified 150V AC)
- Quantity: 4 (2 for each rectified supply)
- Approx. Price: $2.00 each
#### Voltage Regulation (for MOSFET Power Supply)
- Voltage Regulator:
- LM317HV (High-voltage adjustable regulator for 24V output)
- Quantity: 1
- Approx. Price: $3.00
- Resistors for LM317HV:
- R1 = 240Ω, R2 = 4.32kΩ to set output to 24V
- Quantity: 1 each
- Approx. Price: $0.10 each
#### Stability Capacitors for LM317HV
- Input Capacitor:
- 0.1µF, 50V C0G/NP0 ceramic capacitor
- Quantity: 1
- Approx. Price: $0.10
- Output Capacitor:
- 1µF, 50V C0G/NP0 ceramic capacitor
- Quantity: 1
- Approx. Price: $0.20
#### Protection Components
- Bleeder Resistors:
- Vishay PR02 100kΩ, 2W
- Quantity: 2 (one across each large power supply capacitor)
- Approx. Price: $0.50 each
- Soft-Start Circuit Relay:
- Omron G2R-1-E-T130 DC12 (12V, 10A, SPDT)
- Quantity: 1
- Approx. Price: $3.50
- Headphone Output Delay Relay:
- Panasonic TX2SA-LT-12V (12V, DPDT)
- Quantity: 1
- Approx. Price: $2.50
- NTC Thermistor for Inrush Current Limiting:
- Amphenol CL-60 (10Ω, 5A)
- Quantity: 1
- Approx. Price: $1.00
- Fuse Holders and Fuses:
- Schurter OGN-SMD (SMD fuse holder)
- Quantity: 1
- Approx. Price: $2.00
- Littelfuse 37211000000 (1A fuse for MOSFET section)
- Quantity: 1
- Approx. Price: $0.20
- Littelfuse 37221500000 (2A fuse for tube section)
- Quantity: 1
- Approx. Price: $0.25
#### Chassis Components for Power Section
- IEC Filtered PEM:
- Schurter DD12.9111.111 (Filtered IEC connector with integrated switch)
- Quantity: 1
- Approx. Price: $12.00
- Power LED:
- Kingbright WP7113SRD (Red, low-brightness LED)
- Quantity: 1
- Approx. Price: $0.10
---
### 2. Tube Section
#### Tube and Related Components
- Tube:
- 12AU7 Tube
- Quantity: 1
- Approx. Price: $35.00
- Cathode Bias Potentiometer:
- Bourns Potentiometer 3299W-1-103 (10kΩ, adjustable trimmer)
- Quantity: 1
- Approx. Price: $2.00
- Cathode Resistors:
- Vishay PR01 470Ω, 1W
- Quantity: 2
- Approx. Price: $0.20 each
- Grid Stop Resistors:
- Vishay PR01 1kΩ, 1/2W
- Quantity: 2
- Approx. Price: $0.10 each
- Grid Leak Resistors:
- Vishay PR02 1MΩ, 1/2W
- Quantity: 2
- Approx. Price: $0.10 each
- Coupling Capacitors:
- WIMA MKP10 Polypropylene (100nF, 250V)
- Quantity: 2
- Approx. Price: $2.50 each
- Power Supply Smoothing Capacitors (B+ supply):
- Nichicon UVZ2A101MPD (100µF, 250V electrolytic)
- Quantity: 2
- Approx. Price: $1.00 each
#### Heater Supply
- Schottky Diodes for Heater Rectification:
- 1N5819 (40V, 1A Schottky diode)
- Quantity: 2
- Approx. Price: $0.10 each
---
### 3. Transistor (MOSFET) Section
#### MOSFETs and Related Components
- MOSFETs:
- IRLZ44N (MOSFET for amplification)
- Quantity: 2
- Approx. Price: $1.50 each
- MOSFET Source Resistors:
- Panasonic ERX-2SJ0R22 (0.22Ω, 2W)
- Quantity: 2
- Approx. Price: $0.50 each
- Gate Resistors:
- Vishay PR02 10Ω, 1/4W
- Quantity: 2
- Approx. Price: $0.10 each
- Zener Diodes for MOSFET Gate Protection:
- BZX55C15 (15V Zener diode)
- Quantity: 2
- Approx. Price: $0.20 each
#### Decoupling Capacitors
- WIMA MKP10 Polypropylene (0.1µF, 250V for decoupling)
- Quantity: 4
- Approx. Price: $1.00 each
#### Chassis Components for Transistor Section
- XLR Connector (4-pin):
- Neutrik NC4FXX (Female 4-pin XLR connector for headphone output)
- Quantity: 1
- Approx. Price: $4.50
- Volume Potentiometer:
- ALPS RK27 Blue Velvet Potentiometer (50kΩ)
- Quantity: 1
- Approx. Price: $20.00
- RCA Jacks:
- REAN NYS367-0 (RCA input jack, black)
- REAN NYS367-2 (RCA input jack, red)
- Quantity: 2
- Approx. Price: $1.50 each
- Knob:
- Parts Express 240-2218 (Aluminum knob)
- Quantity: 1
- Approx. Price: $7.00
---
### 4. Miscellaneous Components for PCB
#### Mounting Hardware
- **Standoffs, Screws, Nuts
**:
- Harwin R30-3002502 (M3 standoffs, 25mm)
- Quantity: 4
- Approx. Price: $1.00 each
- McMaster Carr 92000A114 (M3 screws)
- Quantity: 8
- Approx. Price: $0.10 each
- McMaster Carr 90695A033 (M3 nuts)
- Quantity: 8
- Approx. Price: $0.05 each
#### Chassis
- Whammy Chassis
- Quantity: 1
- Approx. Price: $120.00
---
### Total Estimated Cost:
- $320 to $370 (excluding PCB manufacturing and assembly)
---
I'll be back in a few hours, but I think I have the BOM completed. Working now with pencil and paper on a rough schematic, will then get it into kicad, assign footprints, design pcb, and get going with this.
Will do. I'll work on it a couple or few hours a day, and upload what I've got so far daily, unless I didn't get to work on my hobby on a given day. I gotta go get some graph paper and a ruler. But I'll have something uploaded today, Lord willing.
Alright, this is what I got. The AI was doing a good job of walking me through, telling me how to space everything out, until we got to the voltage regulator. It described way too small a place, told me a couple things out of order (like telling me to connect output to ground before telling me to put a resistor between them), so we ended up erasing a bit. I hope the rest will fit on this page. If not, I'll expand this and have one sheet per section. This is the power section. I'll pace myself, and do the tube section Friday (tomorrow is already shot for this kinda thing), and the transistor section Saturday or Sunday.
I await your critiques, and thank you for your help.
I await your critiques, and thank you for your help.
Ok, well, this is just the beginning, of course. I still have to add the rest of what's on the power section of the bom. I thought if this is not good enough quality to be useful, it would be better to address that before going much further.