DIY Class A/B Amp The "Wolverine" build thread

Thanks, so in the case of EF3-4 if I choose perpendicular pcb mount I have to follow the original solution for drivers (Q107 & Q108) - these drivers are mounted on their separate 3mm heatsink on each pcb.

To summarize, perpendicular pcb makes measuring and regulations easier and it's healthier for electrolytic caps. Actually all components work in somehow lower temperature than in "pcb on the heatsink" mount. So Q103 in perpendicular case is mounted on the 3mm heatsink between drivers (Q107 & Q108) while Q104 is mounted on the main heatsink and wired to pcb. The original solution is followed and the 3mm heatsink is 75mm long if possible.

Thanks again, for your help,
cheers,
 
Please check the build guide and the latest schematic. Q103 is to be located on the main heatsink and Q104 is mounted in free air as the ambient temperature sensor.
Please clarify:

In the case of EF3-3 that's the correct solution, however in the EF3-4 and perpendicular pcb mount should I follow this EF3-3 solution?
Or as in the original version and perpendicular pcb mount Q104 should be mounted on the main heatsink and wired to the pcb while Q103 is mounted on a separate 3mm heatsink between drivers (Q107 & Q108)?
 
I read build guides from the first one to the last one. I do not know why when designing the board it was decided to place drivers on a separate heatsink. Having power transistors and drivers on the same heatsink would avoid temperature difference problem. Anyway, a separate heatsink for drivers was decided. With two bias transistors placing one on the main heatsink and the other on the drivers' heatsink averages output transistors' and drivers transistors' temperature. That makes sense.

However, over time it has been noticed that placing drivers on the same heatsink as output transistors is a better solution. With pcb mounted on the main heatsink dedicating one bias transistor to sense ambient temperature also makes sense. However, with perpendicular placement of the pcb drivers have to stay on their separate heatsink because of wiring length problem. One bias transistor has to be placed on the main heatsink but I think there is a question what is the optimum placement of the other bias transistor. The point is that with perpendicular pcb ambient temperature of its components is notably lower than the temperature of drivers on their separate heatsink. With pcb mounted on the main heatsink ambient temperature of pcb components is higher and closer to temperature of drivers. So my question is: what is a better solution for perpendicular pcb: to average output transistors' and driver transistors' temperature or average output transistors' temperature with notably lower ambient temperature?
 
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but the latest recommendation is to mount these drivers on the main heatsink. As I prefer to keep pcbs at the right angle to the main heatsink (easy access to pcb trimpots, test points etc) a problem has appeared. If I place drivers Q107 and Q108 on the main heatsink then I have to wire them to the pcb. Can I do this as wires will not be very short?
Janusz, We have made no such recommendations. The drivers can be mounted on either Heatsink.

- I don't see any temperature issues determining the orientation of the PCB (parallel or perpendicular). All the compoments are all going to be in the same chassis and such will all heat up eventually to a similar temperature unless forced ventilation is used. Will the components on the PCB's heat up more if the PCB is mounted parallel with the Heatsink? Maybe, depending on the chassis size and where it is placed. But is this an issue? I don't think so. What are we talking +5 to +10 degrees.... Maybe if you run the amp hard. I personally think your looking at this to closely.


Having power transistors and drivers on the same heatsink would avoid temperature difference problem.
- The whole point of the bias compensation is to keep the voltage across the output emitter resistors relatively constant. If the driver temperature increases, and it increases the bias voltage of the output transistors then temperature rises and it will be sensed and accounted for by Q103. So as long as the size of the driver heatsink is adequate then there's not problem there. The driver heatsinks have been thermally tested and we are happy with the thermal resistance they provide.

- Q104 is detecting ambient. Its like a reference point. I doesn't matter exactly were its mounted unless of course its mounted directly next to a heat source.

-I certainly would not recommend mounting the drivers on the main heatsink and running short wires back to the PCB.

- If you wish to mount your PCB perpendicular to your main heatsink, please just mount Q103 / Q104 as described in the build guide.
That is, mount Q104 in free air and mount Q103 on the main heatsink via fly wires. This is how its described in the build guide and what I recommend.
 
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Really nice @Nikos

I was thinking that there's been a few wolverine builds completed over the past few weeks and it would be great if you or others that have completed their builds would share there thoughts on the wolverine build in a review. You could include things like how you found the build, the documentation and your impressions after listening. I'd be happy to attach your review to the first post so other members new and existing can read it. This may enspire others and give them the confidence to build this project. They may have just come across the Wolverine project or they've been sitting on the fence for some time.

Feel free to post your review here or email it to me and I'll attach it to the first post.

Stuartmp@internode.on.net
 
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Hope someone can answer... C118, C119 and Chelp, I have Mica capacitors: mouser P/N 598-CD15FD471GO3F.
For C5 I have Multilayer Ceramic: Mouser P/N 81-RDE5C2J471J2K1H3B. (For drivers MJE1503X/3X)
Question, would C5 benefit by using 470pf 630v polystyrene? I have some and was just wondering.
Thanks All.
Scott
 
Hi Stuart and everyone else,

In response to your request:-

I completed my build at the beginning of January this year, and I provided a 'first listening' precis, with some photos, in my post #1,003, for those that wish to read that. A bit more than a few weeks ago for sure, but thought a bit of an update might be appropriate.

First of all, I have to say that this thread has been exemplary! Interesting, informative and educational all at the same time! You guys are ace! By the time I'd read through all posts at that time (already lots!), and noted all the advice, considerations, pitfalls, etc. reported by others here together with sound advice from several valued members, I felt as if I knew all there was to know already, before even starting to read the build guide!

Regards the documentation: I found the BOM very easy to understand and, after a little careful thought, the selections to make for my optimum choices was very clear - at that time not too many 'mods, tweaks & updates' had been suggested or applied so it made component selection fairly straightforward for me. It was also evident that a tremendous amount of time and effort had been poured into this project by a number of key members, resulting in the best component choices being clearly suggested. Well done to all!

I found the build guide clear, informative and as long as it was read very carefully ..... twice ..... very easy and logical to follow. As far as my memory serves me I don't recall having any issues at all - build completed, initial measurements taken and adjustments made (bias, etc.), connected up, turned on, and it just worked first time.

Whether it must have helped me or not (!?) although now retired a few years ago I'm guessing my career as a telecomms/electronics development engineer would probably have assisted in my quest. That is, being very familiar indeed with any and all 'through hole' components over many years made the assembly fairly straightforward for me personally. Plus I'd built some previous 'Gainclone' amps over the last few years, so had a reasonable feel for how things should look and work.

However, I honestly feel that the quality of the build guide and all other available information would have allowed virtually anyone who can safely wield a soldering iron, but possessing limited electronics knowledge or experience, to still confidently manage to complete a successful build.

I can also say that, after 7 months or so of regular use, the Wolverine still sounds terrific! I presumed there would be some sort of 'run in' period as components settled in but, honestly, I can't recall this happening - it sounded great from day 1 and still (to me) sounds just about the same - still great! I suppose there must have been some sonic changes, but to my ageing ears I can't tell any difference compared to when it was first switched on in earnest.

So that's my story - if anyone would like any more information, please do shout out!

Best wishes to all,

Richard
 
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I presumed there would be some sort of 'run in' period as components settled in but, honestly, I can't recall this happening
Nope, this is electronics, no such concept as settling in, other than the risk of premature failures (bathtub curve). With only electrons and holes running around in solid state there is nothing really to run in, that's usually an issue with mechanical systems.

Perhaps if you used ancient electrolytics that had been in storage for decades there might be a need to wait for them to reform (minutes or hours only though), that would be a chemical change.

Any anyway a slight change in performance of an amplifier with such high specifications can only be detected with good lab equipment!
 
Hope someone can answer... C118, C119 and Chelp, I have Mica capacitors: mouser P/N 598-CD15FD471GO3F.
For C5 I have Multilayer Ceramic: Mouser P/N 81-RDE5C2J471J2K1H3B. (For drivers MJE1503X/3X)
Question, would C5 benefit by using 470pf 630v polystyrene? I have some and was just wondering.
Thanks All.
Scott
Hard to answer your question as we never tested polystyrene caps in any of the (prototype) boards that we made.
If you have them, use them, as I don't think that they will be an issue.
 
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I completed my build at the beginning of January this year, and I provided a 'first listening' precis, with some photos, in my post #1,003, for those that wish to read that. A bit more than a few weeks ago for sure, but thought a bit of an update might be appropriate.
Thank you for the detailed review Richard. I have added a PDF version to the first post and added a link to your post #2,493

Perhaps it would like to allow those who have completed the construction to evaluate in a few sentences the problems during the construction and satisfaction with the amplifier. All in one post (table).
Great Idea, I will keep and eye on all future posts and add them to a table in the first post.
If you or other members know of any posts that stood out for you or you'd like to to a put together a table with post numbers and a brief description, I will incorporate that into the first post.
 
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I built on the boards from the purchase of the first group. During construction, I followed the instructions from the manual and available videos. During testing, I made one comment, which was accepted by the team, and I did not find any major problem. The only thing that was worrying was that the LEDs on the IPS do not light up (explained by the low supply voltage) and that the bias changes with temperature (today it has already been resolved).
I am very satisfied with the amplifier and it is the best I have built.
If I decide to make improvements in the future, I will rewire the bias and protect the amplifier from overcurrent.
 
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I've bought the Wolverine PCB's together with a set of 1381/3505E-grade and the planing for the build has begun regarding overall parts to source for the project. Mouser is my main site for these purchases, so likely no obsolete parts involved besides the E-grade predrivers.

Seeing the performance of the Wolverine looked like a no-brainer for a good experience and many hours of fun, so I designed to do this one after lots of reading.
Thanks to the V-team for keeping this up and running with a wastly amount of good support in this thread:)

-I have about 50 onsemi MJL1302/3281 witch measure quite well for good pairs.
My current poweramplifier runs ±85vdc rails on MJL1302/3281 and I'm do like some loud listening now and then...
I would like to build this one close to maximum spec ±71VDC, but will the 1302/3281 do?? Think I've read somewhere here in this thread that other outputs were needed, or better, for high rails?

I haven't decided on witch PSU yet... I've done several linier types, so the SMPS seams appealing for sometime new... We'll see

Regards and thanks 👍
 
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