[raindownthunda]

I'm excited about it, but also nervous to a certain extent, I'll feel better when a few people have built it successfully

Yeah there is some flexibility to change parts, depending on the part.

I used a chassis cutout for the RCAs that should fit quite a few different brands, so the builder could choose what they like there assuming their chosen RCA fits.

The potentiometer is a little bit tricky - it has to be a 20-25K pot maximum given the high Miller capacitance of the input stage, otherwise there will be high frequency rolloff. The source impedance of the pot must remain low, 20-25K max ensures that it is. HOWEVER, some ladder type pots, like a TKD, have a higher source impedance than your typical log taper potentiometer, even if they are 20-25K, so I would not recommend using them.

The input stage bypass and coupling capacitors could be changed assuming they fit on the board. But, IMO, I would not recommend changing the bypass caps. I did extensive A-B testing of audio grade electrolytics for the input stage, the Jupiter Cosmos caps were far and away the best, I think using something else in that position would be a step down in performance. I designed the PCB around Jupiter copper foil 0.22uF 400VDC coupling caps, but you could certainly use a different cap in that position as long as it meets the spec and fits.

Dave at Landfall, who makes the chassis, can do different powder coating finishes, so that could be coordinated with him. I will say though that I cannot guarantee how any specific coating will turn out, some powders coat better than others in my experience.

Any change that would require altering a mounting hole in the chassis would need to have the CAD files modified. I'm sorry but I am not likely to volunteer my time to do that for each individual request, but someone could ask Dave at Landfall if he is willing to make the changes for them.

There is a switch to change taps on the output transformer for changing the output impedance to suit different headphones, also using different output tubes will change the output impedance to a minor degree. In general, higher transconductance outputs will result in a lower output impedance and vice versa.

Thanks for the detailed reply! I was mainly trying to get a sense of how much this would be a “modders” amp vs recommend sticking with the spec was designed. I fully trust you’ve done so much experimenting that the parts selected are already as good as it gets. It’s helpful to know what components you’d recommend leaving alone vs where there is some user choice based on preference. Definitely would be unreasonable to expect you to field custom tweaks to chassis, PCB, etc. It‘s already incredibly generous of you to share this design with the community with the goal of making it as easy as possible to build!

 

[L0rdGwyn]

Hey,
Thanks for your great feedback.
Yes, now that you see a picture, I would dare to build it myself.
I'm sure I could get it soldered cleanly in 2-3 quiet Saturday afternoons.

Nothing against the Jupiter condenser, it is certainly very well chosen.is more a question.
What do you think of the Vcap Odam?
Unfortunately it is not available in a 400v version, only in a 630v version, and the new CuTf is only available in 630v.
I have installed the Odam and the TFTF in the Feliks Euforia and found it to be a great added value compared to the standard Mundorf capacitors that are installed.
But I would still be surprised by the Jupiter, which is also supposed to be very good and I think fits very well to the sound tuning.

I haven't tried the V-Cap ODAM, but I have heard good things about them. As long as it fits, 630V version is fine, higher voltage rating is okay, lower voltage rating is not!

Thanks for the detailed reply! I was mainly trying to get a sense of how much this would be a “modders” amp vs recommend sticking with the spec was designed. I fully trust you’ve done so much experimenting that the parts selected are already as good as it gets. It’s helpful to know what components you’d recommend leaving alone vs where there is some user choice based on preference. Definitely would be unreasonable to expect you to field custom tweaks to chassis, PCB, etc. It‘s already incredibly generous of you to share this design with the community with the goal of making it as easy as possible to build!

No problem! I wouldn't necessarily consider it highly moddable, everything has essentially been chosen for a reason, but like I said, there is some flexibility to make some minor changes if people feel strongly about it. Probably the best places to make those changes are the coupling caps, RCAs, color of the chassis, volume knob, and maybe the potentiometer, but as I mentioned, it has to be chosen appropriately for a low source impedance and also fit the same chassis cutout as the Alps.

Also worth noting that I've also made a PCB for the Alps pot to make the soldering and wiring simple. It includes pads for the shields of the RCA input wiring as well as the signal wiring.

 

[DenverW]

Well this is a really pleasant surprise! I'm super excited about this project .

Thank you, thank you, and did I mention thank you?

 

[L0rdGwyn]

Well this is a really pleasant surprise! I'm super excited about this project .

Thank you, thank you, and did I mention thank you?

You're welcome, hoping the project is a success. I think anyone who builds it will be very happy with the sound.

 

[L0rdGwyn]

My one request as this project progresses is that people please be respectful of my time. The documentation I am putting together is going to be very detailed. If all goes according the plan, I'd imagine this thread will grow rapidly and many questions will asked. So please, when that time comes, make sure your question has not already been covered in the build document or already addressed here before asking me.

 

[GanGreinke]

Thank you so much for making this project for the community! I’ll definitely be following along closely!

In regards to the headphone jack, would it be possible to wire the output for other terminations, like a 4 pin xlr jack? It would require some changes to the chassis, but I imagine there are others who also have their cables terminated in other terminations. Maybe you could even offer a chassis option that accommodates panel mounted jacks so that people could use whatever output termination they wanted.

 

[L0rdGwyn]

Thank you so much for making this project for the community! I’ll definitely be following along closely!

In regards to the headphone jack, would it be possible to wire the output for other terminations, like a 4 pin xlr jack? It would require some changes to the chassis, but I imagine there are others who also have their cables terminated in other terminations. Maybe you could even offer a chassis option that accommodates panel mounted jacks so that people could use whatever output termination they wanted.

You're welcome. I'll consider it. It would require making a different CAD file for the front panel for an XLR jack and providing that to Dave at Landfall, then creating separate instructions on how to wire the XLR rather than TRS. Not very appealing to add more work to the pile, especially since this is a single-ended circuit and doesn't require a balanced connector like XLR. Alternatively, one could use a TRS to XLR adapter, or just use a different headphone cable.

 

[DenverW]

My one request as this project progresses is that people please be respectful of my time. The documentation I am putting together is going to be very detailed. If all goes according the plan, I'd imagine this thread will grow rapidly and many questions will asked. So please, when that time comes, make sure your question has not already been covered in the build document or already addressed here before asking me.

In Monsterzero's review video he mentions sending a PM or inquiring with you on the thread. Based on reading the thread that seems premature to me; we seem to be holding as the build instructions are finalized and pieces are put into place. I'll just assume that if there was anything we needed to know or do it would be posted here and hopefully spare you lots of PM's asking the same questions, including from me .

Thank you again.

 

[Monsterzero]

In Monsterzero's review video he mentions sending a PM or inquiring with you on the thread. Based on reading the thread that seems premature to me; we seem to be holding as the build instructions are finalized and pieces are put into place. I'll just assume that if there was anything we needed to know or do it would be posted here and hopefully spare you lots of PM's asking the same questions, including from me .

Thank you again.

In my Airmid review, I had no way of knowing that the opportunity to own one would evaporate in such short order, so although I did mention in the Aegis review it wasnt going to be ready for another 2-3 months, I wanted to put everyone on high alert to get in on the Aegis while the light was still green.
Granted the circumstances between the Airmid and Aegis are quite different with one being a premade amp and the other is a DIY project, I feel that the Aegis is such a great sounding amp at a relatively low price, I wanted everyone to get while the getting is good and to not drag their feet on this.
One never knows what tomorrow may bring.

 

[L0rdGwyn]

In Monsterzero's review video he mentions sending a PM or inquiring with you on the thread. Based on reading the thread that seems premature to me; we seem to be holding as the build instructions are finalized and pieces are put into place. I'll just assume that if there was anything we needed to know or do it would be posted here and hopefully spare you lots of PM's asking the same questions, including from me .

Thank you again.

Yes! Just follow this thread, I will update here when everything is ready to go.

In my Airmid review, I had no way of knowing that the opportunity to own one would evaporate in such short order, so although I did mention in the Aegis review it wasnt going to be ready for another 2-3 months, I wanted to put everyone on high alert to get in on the Aegis while the light was still green.
Granted the circumstances between the Airmid and Aegis are quite different with one being a premade amp and the other is a DIY project, I feel that the Aegis is such a great sounding amp at a relatively low price, I wanted everyone to get while the getting is good and to not drag their feet on this.
One never knows what tomorrow may bring.

Yeah, and I made this thread last minute when I knew your review was going to post, so that's my bad or else I'm sure you would have referenced it.

 

[Monsterzero]

Yeah, and I made this thread last minute when I knew your review was going to post, so that's my bad or else I'm sure you would have referenced it.

I added a link to this thread in the Aegis video description, so its all good.

 

[Bob454]

I'm creating a thread for an upcoming DIY project I am working on, a tube headphone amplifier called the Aegis (pronounced EE-jis). This is a true DIY project, anyone taking on this project would assume full responsibility for acquiring parts, building, and testing the amplifier, although I will be available for questions and guidance if need be. I've placed a very high priority on making this design easy to build with a large portion of the circuitry on a PCB.

At a high level, the power supply is tube rectified, CLCRCRC filtered. The circuit features a choke-loaded 6SL7 input stage, capacitor-coupled to a triode-strapped pentode output stage. The output topology is a transformer-coupled cathode follower, which at this time is the only headphone amplifier of this topology that I am aware of. There is no silicon in this circuit, it is an "old school" tube amplifier design featuring Lundahl transformers and chokes. The amplifier includes a high and low output impedance switch for the purpose of matching high and low impedance headphones.

Tubes for the amp:
-Rectifier - 5V / 2A types; GZ34/5AR4, 5V4/GZ32, 5R4, 274B. 5Y3 can also be used with lower current output tubes like 6V6.
-Inputs - pair 6SL7
-Output - pair power pentodes; 6V6, 6L6, EL34, EL37, KT66, KT77, KT88, 6550. Others as well, compatibility list in progress.

I am currently putting together materials for the project which will include the following:
-Full build of materials (BOM) document with part numbers, prices, and where to source
-Information on ordering the chassis
-PCB gerber files and information on how to order (for those located in the CONUS, I may hold a stock of these PCBs and ship them to individuals on request, more to come on that)
-Project build document that will include amplifier schematics, information on sourcing parts, step-by-step build instructions, testing procedures

This is a relatively expensive design! Pricing of all of the parts is approximately $2,000 USD. However, this is meant to be a TOTL tube headphone amplifier, an equivalent design on the commercial market would be at least 3x the price. Regardless, the project should not be taken on by those who are not willing to commit the time and cost. This amplifier was recently at CanJam SoCal in the ZMF room and there are some forthcoming reviews. Hopefully Head-Fiers will then be able to determine if this is something they'd like to pursue.

At the time of my writing this, I am waiting to receive a second chassis and set of Lundahl components to build a second Aegis for the sake of creating the build document. I anticipate I will have the project posted in its entirety by the end of January at the latest. I will update here as the project develops, it is likely the major documentation and files will be hosted on a thread at diyAudio.com, which will be linked here.

I just watched

I'm creating a thread for an upcoming DIY project I am working on, a tube headphone amplifier called the Aegis (pronounced EE-jis). This is a true DIY project, anyone taking on this project would assume full responsibility for acquiring parts, building, and testing the amplifier, although I will be available for questions and guidance if need be. I've placed a very high priority on making this design easy to build with a large portion of the circuitry on a PCB.

At a high level, the power supply is tube rectified, CLCRCRC filtered. The circuit features a choke-loaded 6SL7 input stage, capacitor-coupled to a triode-strapped pentode output stage. The output topology is a transformer-coupled cathode follower, which at this time is the only headphone amplifier of this topology that I am aware of. There is no silicon in this circuit, it is an "old school" tube amplifier design featuring Lundahl transformers and chokes. The amplifier includes a high and low output impedance switch for the purpose of matching high and low impedance headphones.

Tubes for the amp:
-Rectifier - 5V / 2A types; GZ34/5AR4, 5V4/GZ32, 5R4, 274B. 5Y3 can also be used with lower current output tubes like 6V6.
-Inputs - pair 6SL7
-Output - pair power pentodes; 6V6, 6L6, EL34, EL37, KT66, KT77, KT88, 6550. Others as well, compatibility list in progress.

I am currently putting together materials for the project which will include the following:
-Full build of materials (BOM) document with part numbers, prices, and where to source
-Information on ordering the chassis
-PCB gerber files and information on how to order (for those located in the CONUS, I may hold a stock of these PCBs and ship them to individuals on request, more to come on that)
-Project build document that will include amplifier schematics, information on sourcing parts, step-by-step build instructions, testing procedures

This is a relatively expensive design! Pricing of all of the parts is approximately $2,000 USD. However, this is meant to be a TOTL tube headphone amplifier, an equivalent design on the commercial market would be at least 3x the price. Regardless, the project should not be taken on by those who are not willing to commit the time and cost. This amplifier was recently at CanJam SoCal in the ZMF room and there are some forthcoming reviews. Hopefully Head-Fiers will then be able to determine if this is something they'd like to pursue.

At the time of my writing this, I am waiting to receive a second chassis and set of Lundahl components to build a second Aegis for the sake of creating the build document. I anticipate I will have the project posted in its entirety by the end of January at the latest. I will update here as the project develops, it is likely the major documentation and files will be hosted on a thread at diyAudio.com, which will be linked here.

I just watched the review by @Monsterzero and am interested. Although it's been a while since I worked as an electronics technician, I think this could be right up my alley.

 

[Deleeh]

Hello,

I have another question,
Would it also be possible to build the amplifier in one year, provided there are parts available?
It might be difficult to get the pcb board I guess.
The other parts might be easier to get hold of, and on the condition that capacitors might not be available for another 3-6 months.
The same would probably apply to transformers and other components.

I ask because I personally don't have the $2000 right at my hip and if I were to build it, I would rather build it step by step.
Of course, the components are always completely finished.
Starting, for example, with the purchase of the circuit board,
Later, assemble the parts and the board, later buy the housing and so on until it is finished.

 

[L0rdGwyn]

Hello,

I have another question,
Would it also be possible to build the amplifier in one year, provided there are parts available?
It might be difficult to get the pcb board I guess.
The other parts might be easier to get hold of, and on the condition that capacitors might not be available for another 3-6 months.
The same would probably apply to transformers and other components.

I ask because I personally don't have the $2000 right at my hip and if I were to build it, I would rather build it step by step.
Of course, the components are always completely finished.
Starting, for example, with the purchase of the circuit board,
Later, assemble the parts and the board, later buy the housing and so on until it is finished.

Yeah, that's definitely possible. The only major issue would be if there are longer wait times or a part goes out of stock at the time you decide to move forward to the next step. Where possible, if something goes out of stock, I could indicate substitutes. The most significant cost is the transformers / chokes and their shields, about half of the total cost. It would be best to buy all of those at once since they are made to order. Next most expensive is the chassis. But yes, you could build it in stepwise fashion.

 

[Tom-s]

Does someone have the datasheet for the LL2765 amorphous core? And LL1667 AM 5mA.