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PostPosted: 08 Sep 2019, 03:18 
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For interest,

Here is the other side of the acrylic. :)
I am just looking at the internal illumination the warm white LED's could do with an orange tint its a bit stark but I think orange LED's will be to much. So I will look at a filter.

Woodo wrote:
The beauty almost brings tears. Is the matching shinri concept in the pipeline?


Are you thinking about making one? :D

"shinri" Its something to think about :D :bawling:
So a few things to sort out at the moment, I gave it a quick test last night for a couple of minutes.
The volume steps are spot on I thought the gain would be to high but I already use volume controls on my power amps even then the gain is fine. I'm wondering if the volume drop across the Audio Note balance circuit could be the difference.
The balance control in this configuration is very subtle quite a surprise.
The Black Gates will take some time to burn in so its a few weeks of testing when I get the internal lighting sorted.
There is quite a lot of detail and its quite a warm sound but that's just an initial impression.

My Wife says you need some black plastic plugs for the screws on the side panels er OK :D

Regards
M. Gregg


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PostPosted: 08 Sep 2019, 05:31 
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M. Gregg wrote:
For interest,

Woodo wrote:
The beauty almost brings tears. Is the matching shinri concept in the pipeline?


Are you thinking about making one? :D

Afraid not. Several orders of magnitude below the skill and partner approval level required to take that on. Though quite enjoying the sound of a comparative budget build of the 300b set of @suncalc ‘s and @mwhouston ‘s monoblock concept. Hope to do a better job visually in the future on a 12au7/12au7/6as7 also of suncalc’s design with better thought given to layout and wiring up than my 300b.

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PostPosted: 08 Sep 2019, 06:23 
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Woodo wrote:
Afraid not. Several orders of magnitude below the skill and partner approval level required to take that on. Though quite enjoying the sound of a comparative budget build of the 300b set of @suncalc ‘s and @mwhouston ‘s monoblock concept. Hope to do a better job visually in the future on a 12au7/12au7/6as7 also of suncalc’s design with better thought given to layout and wiring up than my 300b.


I remember you building 300B,

If I remember you had a problem with voltage drop across a rectifier, can't remember exactly what it was now but if you look in the components section on this forum I was looking at rectifiers with reduced voltage drop and power dissipation that might be of interest.
You did a good job most people just look but never seem to get round to building it.

I find it difficult to get the time at the moment with to many work commitments.. :bawling:
Way back in the mid 70's I always wanted to build Ongaku but then listened to gaku-on at a HI-Fi show.
Then Krell etc. I had a listen to the 845 unison as well:
http://www.unisonresearch.com/en/produc ... olute.html

This was a curiosity build really and still is to some extent. The problem with big SE is the room heating up so Ongaku would end up as a pretty door stop LOL. I find 300B amps very variable I guess its the driver section probably being the issue.

Regards
M. Gregg

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PostPosted: 08 Sep 2019, 09:51 
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Just having a quick listen,

I bought some amber tape used to repair car indicators and cut /fitted it to the internal LED's I'll see how it looks tonight.

So I dropped it in the system with the small SE Pye-stream driving Alpair 7's for a test, the trouble is its been on for 3 hours so far and its sounds very good. I'm using the Cyrus CD and playing the Beatles No1's I started with LTJ Bukem "Earth".
Obviously we will see with films etc bass is good but its early days waiting for burn in of the black gates, its interesting that they sound different in this circuit wonder why.

Yes it might be "nice" to create something like a shinri..it would look nice with bronze acrylic side panels.

So a couple of pics it was just dropped in to see what would happen. I have a few other amps I might try it with the OTL next.

A couple of pics of the illumination since the amber tape fitted and a 1K to drop the brightness of the LED's.
The top photo is hand held with some shake but it just gives an idea.
Anyway I guess that's it for now it might be of interest to someone. Exit stage left...

Regards
M. Gregg


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PostPosted: 09 Sep 2019, 06:00 
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The new machine fits in well with your nice setup so no need necessarily for the shinri or ongaku if you’re happy as impressive as they are.

Yes i was having trouble with voltage drop. replacing the hammond 24va transformer with the 30va 6v toroidal transformer, there is now enough voltage after the rectifier (still only 6.8v though) for the lt1085 regulators to supply the filament voltage without much noise. At turn on there’s still a low level for a minute or two before going quiet. I hope i have connected everything right, seems so. Thanks for the tip, will search if there is a bridge rectifier i can use with a lower drop.

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PostPosted: 09 Sep 2019, 14:09 
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Woodo wrote:
Thanks for the tip, will search if there is a bridge rectifier i can use with a lower drop.


Like these:
https://static.rapidonline.com/pdf/1304785_da_en_01.pdf

It depends what voltage you are working with even if its surface mount you can solder to vero board and make a module.
Solder to the track side AKA surface mount. just break the tracks to make a pad board.

Its just an idea.

Regards
M. Gregg

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PostPosted: 10 Sep 2019, 02:08 
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Woodo wrote:
The new machine fits in well with your nice setup so no need necessarily for the shinri or ongaku if you’re happy as impressive as they are.

Yes i was having trouble with voltage drop. replacing the hammond 24va transformer with the 30va 6v toroidal transformer, there is now enough voltage after the rectifier (still only 6.8v though) for the lt1085 regulators to supply the filament voltage without much noise. At turn on there’s still a low level for a minute or two before going quiet. I hope i have connected everything right, seems so. Thanks for the tip, will search if there is a bridge rectifier i can use with a lower drop.

If you use scottky diodes then consrtuct a bridge rectifier then you can get the more voltage.
Try sr5200, low cost and commonly avalible.

I'm not a fan of any lighting, I only like the vaccum tube lighting from heaters.
But I like the fact your looking at all the details when your building the pre amp.


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PostPosted: 13 Sep 2019, 01:43 
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Thanks will see what I am able to source. Rs components don't seem to have the panjit unit here in Aust.

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PostPosted: 14 Sep 2019, 04:05 
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Woodo wrote:
Thanks will see what I am able to source. Rs components don't seem to have the panjit unit here in Aust.


As you know its the forward voltage drop you are reducing, so its Vf on the spec sheet.
So power dissipated in the device is the forward voltage drop X the current drawn through the device.
Which is the same as volts X amps = watts :arrow:
So low power dissipation devices don't heat up like "regular" diodes.
So in a nutshell you are trying to reduce Vf.
Schottky diodes aren't perfect and do have reverse leakage problems but that's a different issue.
https://www.youtube.com/watch?v=xxoevV-B318

So if I use them in diode bias I tend to have a "standard" diode in series with a Schottky. :D
Sorry I wandered off topic :D
Another for fun:
https://www.youtube.com/watch?v=bXEyCf1P0UU

Regards
M. Gregg

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PostPosted: 15 Sep 2019, 05:37 
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Thanks. off-topic? No, knowledge shared is like gold to me. I see the Vf of my gbu4a is say 1v at 4a and if I read correctly the chart of voltage v current, at my 1.2A for the 300b heater Vf should be a tad less say 0.9v. I recall Koichi may have mentioned that is per diode conducting? so say 1.8v. if that is all the voltage drop the dissipation is 2.16w. The panjit schottky mentions 0.62v Vf per diode i recall so dissipation should be about 1.5w. If right that is quite a difference. I see there are also thermal resistance differences between the two which I haven’t yet processed what they mean. The numbers seem to go in the wrong direction intuitively to me.

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