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Blue Hawaii BJT Build thread

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2 minutes ago, Helium said:

What are the consequences if you just wire jumper 5R1?

no current limiter, and less filtering ...if you don't want current limiter, remove 3904 rather

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23 minutes ago, sorenb said:

assume you GRHV voltage out is 390V under load and +404 and -410 without? what is the voltage at the drain of the Sic (middle leg) against ground? 
and what is the voltage between R9/R7?  both with and without load

Details are:

Raw AC from trfo: 2x 315V @ 330ma each

Unregulated DC: 436V

Regulated B+: +404 no load, +392 load

Regulated B-: -410 no load, -383 load

SiC drain is 8.3V under load. 

will measure other in a bit...  Thanks sorenb.

Edited by Blueman2

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44 minutes ago, Blueman2 said:

Details are:

Raw AC from trfo: 2x 315V @ 330ma each

Unregulated DC: 436V

Regulated B+: +404 no load, +392 load

Regulated B-: -410 no load, -383 load

SiC drain is 8.3V under load. 

will measure other in a bit...  Thanks sorenb.

secondaries are too low for getting 400V out ... try 375V rather ...lower the two 390k to 365k, or parallel to get there

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18 minutes ago, sorenb said:

secondaries are too low for getting 400V out ... try 375V rather ...lower the two 390k to 365k, or parallel to get there

Thanks.  Is there much of an issue running a BH BJT at only 375V?  Either that or I will get a 350V rated trafo.  Just not sure the larger trafo will fit into this case.  Things are really, really tight in there right now.   

Edited by Blueman2

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1 minute ago, Blueman2 said:

Thanks.  Is there much of an issue running a BH BJT at only 375V?  Either that or I will get a 350V rated trafo.  Just not sure the larger trafo will fit into this case.  Things are really, really tight in there right now.   

no issue running it a bit low, and leave it at that.

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Running like a dream now!  Thanks mwl168 and sorenb for the fixes.  I reduced the amp to +375v and -378v by overlaying 4M7 resistor in parallel to the 390K ones, and it is holding rock solid.  Loaded or unloaded, same numbers.  And with the 2R6 on the B- current limiter, it is handling the 135ma on that rail without issue.  I did not have to change the B+ side current limiter.  Frankly, I would never have solved the current limiter issue without your guidance, mwl168.  

Just spent about 10 minutes on the BH using some older Lambda Pro's that I use to test amps (if they get fried, I will not cry).  Now to plug my 007's in and lose a couple hours of time....

Edited by Blueman2
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Got the filaments down to exactly 6.0VAC using 0.3R 5W resistors.  B+ and B- are both solid now as well.  +375V and -378V.  About 0.2 drift over 30 minutes of warm up then stays fixed after that.  Still comparing to my SRX and Carbon, but the sound is certainly glorious!  I know, pics or it didn't happen.  So....

 

20180120_202149.thumb.jpg.766af8add1fa539c406a0a39d6d03529.jpg

Above, you can see that in order to make this fit in a 300mm deep case, I had to create 2 layers of boards.  PSUs on bottom, Amps on top, with about 30-40mm of overlap.  There was actually plenty of clearance and I could have moved them to overlap even more if needed.  I was able to leave enough room in front for the power switch and future quad pot when it arrives.  Please don't give me too much crap for the messy wiring.  I plan to take it apart next week to add the quad pot and clean up the internal build a bit.  I just wanted to prove to myself that it would fit!

Also, notice that I am using the 755-SCT2H12NZGC11 as a replacement for the C2M1000170D for the PSUs.  It appears to work just fine and runs cool. So we do appear to have a backup device for when the C2M1000170D SiC is out of stock.  

Also, in the front middle (under the mess of wires) is a timer delay for the CPC1117 HV delay turn on, as referenced earlier in this thread.  I have it set for 60 seconds.  

 

 

20180120_202552.thumb.jpg.ccf3fc8b83824ca0d45851acb7a632ec.jpg

Above with the tube cages.  I have not install yet, but just wanted to see how they will look.  That will be next week...

 

20180120_204451.thumb.jpg.639ccf50cbd3d37389387cbd60f9678c.jpg

And finally, sharing some room with my Carbon.  Not pictured are my SRX builds (one mine, one my son's).  BTW, so far, the BH runs cooler (both case temp and silicon temps) than my Carbon.  Both running at 20ma.  

Edited by Blueman2
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Big fan of 3d space optimization for amps. Haven't managed to implement it yet but this is giving me inspiration :D Do you have a link to the case you used? What do those four mounting holes on the faceplate do since it looks like the plate is actually held in by those corner post block things? 

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The case is available in several configurations from several sellers on eBay.  Search on "BZ4309" or just "4309 aluminum chassis".  Mine was a great price: $110 including shipping and arrived from China in 4 days!   Seems like the price jumped to $150 or more now, so I was lucky.  The holes are for rack mount front handles.  I did not like the look and plan to tap holes and put aluminum screws in the front to cover the holes.      

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Stick some LEDs in 'em.....

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On 1/21/2018 at 12:32 AM, joehpj said:

Any comparison?

I am not good at putting words to what I hear, but let me give it a try.  This is on my SR-007 with blu-tak mod.  

The Carbon is more crisp, but more 'in my head' in terms of sound stage.  The Blue Hawaii has more body and a noticeably wider sound stage.  While the Carbon appears to highlight higher frequencies, I find that cymbals and the metallic 'sizzle' sound of a snare sound better on the BH than the Carbon.  Backward from what I expected. The reason I tend to really like the BH is that it excels at warm and full, but does not sacrifice high frequencies and fast transients in any way.  Its ability to do both so well is what struck me the most as I started to get used to it. 

I can make the BH sounds more like the Carbon and vice-versa by using frequency equalization in foobar player.  So it appears much of the difference I hear is related to which frequencies each amp peaks on.  It is also interesting that I was expecting the Blue Hawaii to sound more like the SRX-Plus since they are both tube amps.  But I find the SRX is just as different from the BH as the BH is from the Carbon.  3 very different amps.  

With flat equalization, I tend to like the BH best right now.  I listened to the BH for 1 hour, then the Carbon for 1 hr.  Not scientific, but I just enjoyed the BH better.  As JimL has said, it is always the new girl who gets the most attention, and perhaps that is what is going on here.  After building the Carbon, I felt it was better than the SRX, but after a few weeks I found myself using both pretty much equally.  

I am very happy with these 3 amps and am indebted to this community for all the help in choosing and building them.  I am also glad I have all 3 because they are all different and great in their own way.  

EDIT: FYI, my source is a Gungnir Multibit ('Gumby') using balanced out into both the Carbon and the BH.  

Now on to more listening.....  

Edited by Blueman2
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In case anyone should want to know, I measured the power usage for the Carbon, Blue Hawaii and SRX-Plus.  

  • SRX-Plus (using BHUltraMini PSU @ 350V) = 53 Watts
  • Carbon (using GRHV PSU @ 400V) = 92 Watts
  • Blue Hawaii (using GRHV PSU @ 375V) = 140 Watts
 
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On 1/20/2018 at 9:57 PM, Blueman2 said:

Got the filaments down to exactly 6.0VAC using 0.3R 5W resistors.  B+ and B- are both solid now as well.  +375V and -378V.  About 0.2 drift over 30 minutes of warm up then stays fixed after that.  Still comparing to my SRX and Carbon, but the sound is certainly glorious!  I know, pics or it didn't happen.  So....

 

20180120_202149.thumb.jpg.766af8add1fa539c406a0a39d6d03529.jpg

Above, you can see that in order to make this fit in a 300mm deep case, I had to create 2 layers of boards.  PSUs on bottom, Amps on top, with about 30-40mm of overlap.  There was actually plenty of clearance and I could have moved them to overlap even more if needed.  I was able to leave enough room in front for the power switch and future quad pot when it arrives.  Please don't give me too much crap for the messy wiring.  I plan to take it apart next week to add the quad pot and clean up the internal build a bit.  I just wanted to prove to myself that it would fit!

Also, notice that I am using the 755-SCT2H12NZGC11 as a replacement for the C2M1000170D for the PSUs.  It appears to work just fine and runs cool. So we do appear to have a backup device for when the C2M1000170D SiC is out of stock.  

Also, in the front middle (under the mess of wires) is a timer delay for the CPC1117 HV delay turn on, as referenced earlier in this thread.  I have it set for 60 seconds.  

 

 

20180120_202552.thumb.jpg.ccf3fc8b83824ca0d45851acb7a632ec.jpg

Above with the tube cages.  I have not install yet, but just wanted to see how they will look.  That will be next week...

 

20180120_204451.thumb.jpg.639ccf50cbd3d37389387cbd60f9678c.jpg

And finally, sharing some room with my Carbon.  Not pictured are my SRX builds (one mine, one my son's).  BTW, so far, the BH runs cooler (both case temp and silicon temps) than my Carbon.  Both running at 20ma.  

 

Nice!  BTW, probably the reason the BH is running cooler is that you've got 70+ watts sitting outside the case (those 4 EL34s at 9 watts filament power plus 9 watts plate dissipation per tube).

Edited by JimL
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3 hours ago, JimL said:

 

Nice!  BTW, probably the reason the BH is running cooler is that you've got 70+ watts sitting outside the case (those 4 EL34s at 9 watts filament power plus 9 watts plate dissipation per tube).

Yea, that must explain it.  I had been warned that the BH BJT runs really hot, so was expecting more heat from it.  So far, it is maxing out at 39 °C on the heat sinks, and 45-48°C on hottest silicon.  Carbon is running 3-5 degrees hotter.  Of course, both cases have pretty large heatsinks due to single PSU/AMP case design, which probably helps.  

12 hours ago, jose said:

You need a Megatron... emoji16.pngemoji16.png

<FEAR> Nooooooooooooooooooooooooooo!  </FEAR>  Must resist even reading Megatron thread.  Must repeat to myself: I do not need another amp.  I do not need another amp.  I do not need another amp......    

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You don´t know the power of the dark side!

 

vader-1_5e8a782d.jpg

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I am getting quite a drift in offset for my BH BJT.  To get it to zero out at full warm up (about 50 minutes), I have to start it at -45V on one side and -35 on the other.  Balance stays good on both sides, starting around 3-4V but always getting to less than 0.5V at full warm up.  In a discussion with JoaMat regarding Servo1 vs. Servo2 for Carbon, he mentioned it would be possible to do a daughterboard for the BH and tie it in to tame the offset drift.  Looking at the schematics, the BH BJT and the Carbon (and for that matter all of the KG designed ES amps I have seen) share a very similar architecture, so transferring the Servo design should be doable.  I think JoaMat did this successfully.  Has anyone else done this?   

I was going to try to come up with a schematic for the daughterboard and how to tie it in to an existing BH, but wanted to see if I could leverage off the work of others first.  BTW, if I am wasting my time worrying about the offset on the BH, please tell me.  Or if there is another way to attack offset, I would be curious.  I moved tubes around and that did not seem to make much difference.  

Big thanks to JoaMat who gave me nice background and tutorial on the Servos.

  

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If in the GG the servos work perfectly, in the BH it should work. However I think that the nature of the beast is that ... don´t use servos

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I’ve used a couple of different offset servos with a Blue Hawaii. I found them very useful. If you like 45 volts drift you should avoid all kind of servos.

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On 1/30/2018 at 1:44 PM, jose said:

If in the GG the servos work perfectly, in the BH it should work. However I think that the nature of the beast is that ... don´t use servos

I agree that the servo on the BH is probably not necessary.  It is fine after about 10-15 minutes warm up.  But I love a challenge, and getting a servo installed on my BH sounds like as good a challenge as any.  JoaMat is kindly giving me some advice and direction, and I will report back when I have a pair of servo daughter boards created and working for the BH (fingers crossed).  

Back on the topic of the BH BJT itself, it really is an amazingly pleasant amplifier.  Yet I can't say what it is about the amp that is so good.  A/B testing with my Carbon and SRX don't really tell me anything.  I honestly cannot tell a big difference.  Yet listening to the BH for an hour or two leaves me feeling so good, whereas the Carbon is a bit more fatiguing.   Not saying the Carbon is not great, I just find it less suitable for listening to for a couple hours while doing other work.  I find I am using the BH for my 'ambient' amp, where I want to listen to music for hours at a time while doing other tasks.  I tend to use the Carbon for my 'critical listening' amp where I want to really focus on the music without other distractions, at perhaps a bit higher volume level.  My SRX is a great amp for both use cases.  

 

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My BH starts with 30mVolt  30 volt and needs 15~30 minutes warm up. After, offset is arround  5 ~ -5mVolt. 

 

 

 

Edited by jose
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25 minutes ago, jose said:

My BH starts with 30mVolt and needs 15~30 minutes warm up. After, offset is arround  5 ~ -5mVolt. 

 

 

 

Is it 30V or 30mV? 

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