Thanks so much for the info, Stuart. Could you please change my registration from a EF3-4 blue to a EF3-3 blue? Thanks so much and sorry for the change of mind
Hi Stuart & the Wolverine project team,
First, I want to thank you all for an amazing diy project. I am new to this forum and greatly appreciate what you guys are doing in the development of the Wolverine project.
Second, I am interested in purchasing the EF3-4 board and would like to know if it is too late to purchase through the Buy Group 4 process? Also, I need to confirm whether the entries for boards in the purchasing spreadsheet mean that if I enter a 2 in the spread sheet for the number of boards that it means the equivalent to specifying the 1 set of 2 boards as those terms are used in the announcement post for the Buy Group 4 purchase process. I want to end up with 2 EF3-4 boards at the $55.00 per set rate, so what quantities should be specified in the spreadsheet to be consistent with this? My confusion is with "sets' verses "boards" used in the spread sheet. It is my understanding that they come is sets of 2 or 4 boards as the basic offering. In other words, I am interested in 1 set of 2 EF3-4 boards.
Third, I want to confirm the revision number that will be on the EF3-4 boards. I have seen recent photos of up to EF3-4(V4.2). Will this be the board revision if purchased through Buy Group 4? And, if a board revision is underway already, what time frame is estimated for the revision to be completed and available? I understand that the boards could be revised between Buy Group cycles due to improvements over time.
Fourth, can you share the latest schematic drawing, BOM, component detail documents, and Build Guide Doc for the project so I can get a head start on component purchases and power supply design and build, etc..
Fifth, do you have up-to-date LTSPICE or QSPICE files of the project for doing simulations? I would find these to be a tremendous help in looking at the testing setup steps through the build process.
Thank you for your time,
Robert
First, I want to thank you all for an amazing diy project. I am new to this forum and greatly appreciate what you guys are doing in the development of the Wolverine project.
Second, I am interested in purchasing the EF3-4 board and would like to know if it is too late to purchase through the Buy Group 4 process? Also, I need to confirm whether the entries for boards in the purchasing spreadsheet mean that if I enter a 2 in the spread sheet for the number of boards that it means the equivalent to specifying the 1 set of 2 boards as those terms are used in the announcement post for the Buy Group 4 purchase process. I want to end up with 2 EF3-4 boards at the $55.00 per set rate, so what quantities should be specified in the spreadsheet to be consistent with this? My confusion is with "sets' verses "boards" used in the spread sheet. It is my understanding that they come is sets of 2 or 4 boards as the basic offering. In other words, I am interested in 1 set of 2 EF3-4 boards.
Third, I want to confirm the revision number that will be on the EF3-4 boards. I have seen recent photos of up to EF3-4(V4.2). Will this be the board revision if purchased through Buy Group 4? And, if a board revision is underway already, what time frame is estimated for the revision to be completed and available? I understand that the boards could be revised between Buy Group cycles due to improvements over time.
Fourth, can you share the latest schematic drawing, BOM, component detail documents, and Build Guide Doc for the project so I can get a head start on component purchases and power supply design and build, etc..
Fifth, do you have up-to-date LTSPICE or QSPICE files of the project for doing simulations? I would find these to be a tremendous help in looking at the testing setup steps through the build process.
Thank you for your time,
Robert
Hi @rlwse,
2. Yes the group buy is still open. I'm planning to order this weekend.
We always order a few extra boards anyway due to quantity breaks etc.
Regarding the order sheet, if you put 1 set, 1 pair or you put 2 boards I know what you're talking about. But for clarity 1 set means two boards, 1 pair means two boards and two boards is two boards all being enough for 1 stereo amplifier.
3. The revision numbers will 4.9 for the IPS and 4.2 for the EF3-3, EF3-4.
4. There will be a new schematic and bom coming out in due time. Its basically the same as the current one except we tweaked a few component IDs to make things clearer. The bom will reflect that. We have also added an option for two extra rail decoupling capacitors for the EF3-4 board and given a few smd options.
All that will come out in due time. The current files excluding the bom are attached to 1st post of the build thread. You will receive access to the bom and other support files once your order is shipped.
5. The ltspice file is not being shared at this time.
2. Yes the group buy is still open. I'm planning to order this weekend.
We always order a few extra boards anyway due to quantity breaks etc.
Regarding the order sheet, if you put 1 set, 1 pair or you put 2 boards I know what you're talking about. But for clarity 1 set means two boards, 1 pair means two boards and two boards is two boards all being enough for 1 stereo amplifier.
3. The revision numbers will 4.9 for the IPS and 4.2 for the EF3-3, EF3-4.
4. There will be a new schematic and bom coming out in due time. Its basically the same as the current one except we tweaked a few component IDs to make things clearer. The bom will reflect that. We have also added an option for two extra rail decoupling capacitors for the EF3-4 board and given a few smd options.
All that will come out in due time. The current files excluding the bom are attached to 1st post of the build thread. You will receive access to the bom and other support files once your order is shipped.
5. The ltspice file is not being shared at this time.
Hi Guys,
I've been looking at the list of approved output BJTs. I'm interested in devices that will run on approximately 71 V rails. When the spreadsheet indicates that the devices have been tested does that mean that the amplifier meets its design specifications when those transistors are deployed? Also, it's hard not to notice that the price of some of these devices are five times or more than the price of others I'll need eight pairs. Is there any qualitative difference among these different transistors or do the prices vary because of manufacturing quantities? Also, I was not aware of the MT-200 package before now. I love the way they look.....but as you know SanKen has discontinued production. I would be reluctant to build an amplifier that could not be fixed due to a discontinued part. And where would you source insulators for those things? You'd probably have to use Kaptan Tape....correct? How do most builders select among the various transistors? Also, when looking at the data sheets what parameter tells you that this transistor needs 71 V versus one that requires 59 V ot 64 V?
My plan is to secure the output transistors first, and then order the appropriate transformers. So far I have a Modushop 5U diyaudio chassis and the boards for the EF-4 version from Group Buy 3. I'm glad to see interest in the Wolverine has generated a 4th Group Buy. The Wolverine Design Team has really done a great job.
I'd be grateful for any assistance,
John
I've been looking at the list of approved output BJTs. I'm interested in devices that will run on approximately 71 V rails. When the spreadsheet indicates that the devices have been tested does that mean that the amplifier meets its design specifications when those transistors are deployed? Also, it's hard not to notice that the price of some of these devices are five times or more than the price of others I'll need eight pairs. Is there any qualitative difference among these different transistors or do the prices vary because of manufacturing quantities? Also, I was not aware of the MT-200 package before now. I love the way they look.....but as you know SanKen has discontinued production. I would be reluctant to build an amplifier that could not be fixed due to a discontinued part. And where would you source insulators for those things? You'd probably have to use Kaptan Tape....correct? How do most builders select among the various transistors? Also, when looking at the data sheets what parameter tells you that this transistor needs 71 V versus one that requires 59 V ot 64 V?
My plan is to secure the output transistors first, and then order the appropriate transformers. So far I have a Modushop 5U diyaudio chassis and the boards for the EF-4 version from Group Buy 3. I'm glad to see interest in the Wolverine has generated a 4th Group Buy. The Wolverine Design Team has really done a great job.
I'd be grateful for any assistance,
John
Hi John,
Take the following with some salt;
Outputs (and preceding stages) are dependent on speaker load and rail voltages. Assuming you have a BOM, you already know you are using 71V, so are the speakers you plan on using with the amplifier difficult to drive? This will narrow your choices. Are you using 3 or 4 output pairs? Again, narrows your choices. Linear supply or SMPS? Smaller again.
I believe all of those outputs have been tested by various build team and general forum members. (slight tangent, probably the slowest Sanken drivers 2SC4832 and 2SA1668 would be everyone's last pick however, but they do work fine I have tried them). Use parts not on that list if you want to break something and hurt your wallet.
The price differences between output transistors do vary due to manufacturing quantities and also age of manufacturing processes. I believe the onsemi's use a more modern production process, allowing them to get much better part (gain and Vbe etc) matching and make the transistors more economically. Notice how the Onsemi's don't seem to have "grades", whereas the Sankens do? Yeah, the Sanken process seems to be much less predictable as to what transistors they get out of the wafers compared with other processes. If you order Sankens, you cant choose what grade you want, you just get whatever shows up. At least with the onsemis, no need to "grade". I'm not hating on Sankens, in fact I'm using them, I'm just saying what I observe.
The MT-200's are neat, but sadly obsolete. I got mine out of old Audiolab multichannel amps, resulting in poor HFE & Vbe matching*. Any parts you do manage to get have a chance of being fakes, and a slim chance of matching nicely. There is a forum member in the swap meet section selling pairs of supposedly NOS 2SC3264's and 2SA1295's. Arguably the most robust audio power transistor ever made. Use Mica insulators for these that are still available on aliexpress, and they work perfectly fine.
I'm not certain on this - but I think the most desirable feature in transistors for audio application is linear hFE across a wide collector current range, with the lowest beta droop at high currents/loads. Followed by low capacitance (easier to turn on / off the transistor) and high switching speeds for high amp bandwidth.
The parameter that tells you how "robust" a transistor is (generally) is the SOA - Safe Operating Area. Hard to read if you are new, but trust the build team have sized the outputs to the correct rail voltages as per the BOM.
I see you have EF3-4 boards. If your speakers aren't in the the 1% really difficult to drive, and you haven't purchased predrilled heatsinks, my recommendation would be NJW3281/1302 (or MJL3281/1302 for TO-264) outputs for your build. I bought only the 16x I need for my next build and the Vbe and HFE matching on them is insanely close compared to everything else I've seen. These are modern parts that aren't going to go obsolete soon (touch wood). I also grabbed some Toshiba 2SC5200N and 2SA1943N because they are cheap as, but the matching was horrible so they in the spares bin. Get what you pay for. If your heart is set on Sanken use the 2SC2363/1294's. The ones I salvaged from old amps and from what I've read here, they match up well too but dont seem to be as "linear" as the onsemi's.
@stuartmp will likely chime in and correct me where I'm wrong so wait for others to comment before loading up a cart. Also, I don't have the awesome test equipment that he has, so he has far more experience re transistor specs.
For what its worth these outputs are probably best avoided unless you have spares or are willing to hunt:
2sc6145/a 2sa2223a - discontinued and stocks clearing. Couldn't guarantee what grade parts would turn up. Look very fast and linear? similar to 3281/1302's?
all Sanken MT-200's (3264, 1295, 2922 and 1216)- obsolete
*matching outputs is not strictly required on the wolverine due to the design
Take the following with some salt;
Outputs (and preceding stages) are dependent on speaker load and rail voltages. Assuming you have a BOM, you already know you are using 71V, so are the speakers you plan on using with the amplifier difficult to drive? This will narrow your choices. Are you using 3 or 4 output pairs? Again, narrows your choices. Linear supply or SMPS? Smaller again.
I believe all of those outputs have been tested by various build team and general forum members. (slight tangent, probably the slowest Sanken drivers 2SC4832 and 2SA1668 would be everyone's last pick however, but they do work fine I have tried them). Use parts not on that list if you want to break something and hurt your wallet.
The price differences between output transistors do vary due to manufacturing quantities and also age of manufacturing processes. I believe the onsemi's use a more modern production process, allowing them to get much better part (gain and Vbe etc) matching and make the transistors more economically. Notice how the Onsemi's don't seem to have "grades", whereas the Sankens do? Yeah, the Sanken process seems to be much less predictable as to what transistors they get out of the wafers compared with other processes. If you order Sankens, you cant choose what grade you want, you just get whatever shows up. At least with the onsemis, no need to "grade". I'm not hating on Sankens, in fact I'm using them, I'm just saying what I observe.
The MT-200's are neat, but sadly obsolete. I got mine out of old Audiolab multichannel amps, resulting in poor HFE & Vbe matching*. Any parts you do manage to get have a chance of being fakes, and a slim chance of matching nicely. There is a forum member in the swap meet section selling pairs of supposedly NOS 2SC3264's and 2SA1295's. Arguably the most robust audio power transistor ever made. Use Mica insulators for these that are still available on aliexpress, and they work perfectly fine.
I'm not certain on this - but I think the most desirable feature in transistors for audio application is linear hFE across a wide collector current range, with the lowest beta droop at high currents/loads. Followed by low capacitance (easier to turn on / off the transistor) and high switching speeds for high amp bandwidth.
The parameter that tells you how "robust" a transistor is (generally) is the SOA - Safe Operating Area. Hard to read if you are new, but trust the build team have sized the outputs to the correct rail voltages as per the BOM.
I see you have EF3-4 boards. If your speakers aren't in the the 1% really difficult to drive, and you haven't purchased predrilled heatsinks, my recommendation would be NJW3281/1302 (or MJL3281/1302 for TO-264) outputs for your build. I bought only the 16x I need for my next build and the Vbe and HFE matching on them is insanely close compared to everything else I've seen. These are modern parts that aren't going to go obsolete soon (touch wood). I also grabbed some Toshiba 2SC5200N and 2SA1943N because they are cheap as, but the matching was horrible so they in the spares bin. Get what you pay for. If your heart is set on Sanken use the 2SC2363/1294's. The ones I salvaged from old amps and from what I've read here, they match up well too but dont seem to be as "linear" as the onsemi's.
@stuartmp will likely chime in and correct me where I'm wrong so wait for others to comment before loading up a cart. Also, I don't have the awesome test equipment that he has, so he has far more experience re transistor specs.
For what its worth these outputs are probably best avoided unless you have spares or are willing to hunt:
2sc6145/a 2sa2223a - discontinued and stocks clearing. Couldn't guarantee what grade parts would turn up. Look very fast and linear? similar to 3281/1302's?
all Sanken MT-200's (3264, 1295, 2922 and 1216)- obsolete
*matching outputs is not strictly required on the wolverine due to the design
Stuart,
Thank you so much for your feedback. Being new to this forum, I have decided not to rush an order in Buy Group 4. I will take some more time to read through the build thread and other Wolverine topical threads to see if there are further considerations that would influence my ordering. I am willing to wait for the next Buy Group for this purpose.
Thanks,
Robert
I'm thrilled to report that our 4th group buy has been a massive success! We've been completely blown away by your enthusiastic response, and it's clear we've gathered a fantastic community here.
Here are the latest updates:
- The PCBs are currently loaded and waiting at the PCB house. After rechecking the boards everything is set to move forward smoothly.
- Color Selection: As voted by the majority, the PCBs will feature a matte black finish. We're excited to see how these new boards turn out. Matte black is one of my favourites.
- I will finalize the order on Monday when the PCB house reopens.
Thank you all for your active participation and support you've given to the Wolverine project. This wouldn't have been possible without you guy!
Stay tuned for more updates after we finalize the order and production begins.
Here are the latest updates:
- The PCBs are currently loaded and waiting at the PCB house. After rechecking the boards everything is set to move forward smoothly.
- Color Selection: As voted by the majority, the PCBs will feature a matte black finish. We're excited to see how these new boards turn out. Matte black is one of my favourites.
- I will finalize the order on Monday when the PCB house reopens.
Thank you all for your active participation and support you've given to the Wolverine project. This wouldn't have been possible without you guy!
Stay tuned for more updates after we finalize the order and production begins.