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04-19-2017 Post does not mapped to Knowledge Tree
anthony
Posts 191
Joined on 08-18-2014

Post #: 126
Post ID: 23174
Reply to: 23173
No, no Pieter
Lucas Cant from Black Art Automation in Melbourne.  I cannot recommend him highly enough.
04-23-2017 Post does not mapped to Knowledge Tree
anthony
Posts 191
Joined on 08-18-2014

Post #: 127
Post ID: 23182
Reply to: 23166
EM Shielding, do or don't?
 anthony wrote:
...you've got me thinking about this now.  I'll talk to some people here and see what they think, but it should be easy enough to place a shield between the OPT's and the tube bases.

Thanks for bringing it up.  I am looking for other angles to view the design, and yourself and Jarek have been very helpful.



I've talked to my advisers here about the potential EM induction at the tube sockets from the various OPT's situated beneath.  It is not easy to see on the sketches, but absolute minimum separations are 60mm for the smaller, high frequency OPT's and 75mm for the huge Bass OPT.  Basically, because the voltages are relatively low at about 200VDC those minimum separations are expected to be "plenty".  

If this was a 211 amp with 1800V on the plate then there would definitely be an issue even at 40cm...shielding would be essential.

So I am going to go without shielding in those locations for now.  If I have problems then I should be able to retrofit something, but fingers crossed that will not need to happen.

Thanks for bringing it up guys.
04-23-2017 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,144
Joined on 10-12-2006

Post #: 128
Post ID: 23183
Reply to: 23182
Mock-up
That's good news, Anthony; no sense doing something like that just to do it.  If you really wanted to, you could fire up the trannies and measure the fields.


Best regards,
Paul S
11-23-2017 Post does not mapped to Knowledge Tree
anthony
Posts 191
Joined on 08-18-2014

Post #: 129
Post ID: 24574
Reply to: 23183
Some more DSET photos..
My DSET amplifiers are starting to go together (slowly).

Bias string and bleeder relays/resistors...

Bottom Floor Done 1.jpg


The remainder of the filter caps.  
Bottom Floor Done 3.jpg


The middle floor goes on and the filter cap for the First Stages (6E5P/6E6P).

2nd Floor in place 3.jpg


Then the OPT's go in place and the shelf that has most of the bias pots and lpads...
A wee bit more.jpg

A wee bit more 2.jpg

A wee bit more 3.jpg

The big Bass OPT is finalised in place but the other OPTs are just sitting there and awaiting more wiring.


02-14-2018 Post does not mapped to Knowledge Tree
anthony
Posts 191
Joined on 08-18-2014

Post #: 130
Post ID: 24695
Reply to: 24574
DSET labels
I am making steady progress putting together my DSET amplifiers.  Life and work gets in the way but I am chipping away at it, taking my time, not rushing, enjoying it.  Wow, it is a lot of work and an enormous task for my first complete amplifier build but I'll get there in the end.

Today I picked up from the signwriter some little stickers for the ammeters on the amplifier.  There is even a spare sticker just in case I end up with a Midbass Channel rather than the Injection Channel.

In Place 1.jpg


In Place 2.jpg


I hope to begin power-on testing of the first DSET in the next week or two...it's getting close...

Almost ready.jpg

Almost ready 2.jpg

02-15-2018 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,535
Joined on 05-28-2004

Post #: 131
Post ID: 24696
Reply to: 24695
Some thoughts.
You decided to go with mA or are they mV against 1R resistors? I prefer the second approach personally and I feel that I can moderate the quality of resistor and I can’t moderate the quality of the milliampere meter coil. 
 
The whole thing looks like very well thought out. A few comments I would like to pass. 
 
You are right now in a very interesting state when you do the internal wiring. The internal wiring. Is to a degree is an art form and it might be very interesting. There are low and high voltages, AC and DC, twisting and not, crossing with minimum angles, some transmission line considerations, signal wires, grounding, approximations, shortening wire paths, maintainability, ease to access and many other considerations that you need to keep in perspective. It is very interesting and creative phases, do not harry to go through with it, spend some time and do it better and methodological. Do the same wiring schema for both R and L amplifiers. When you will be doing the second amp you will find better way to wire it. It is debatable if you want to improve the second one or to the second one as a direct replica of the first one. BTW, did you do it as two identical or you went full-throttle and made it mirroring? 
 
Also, if everything is works fine then the only part that you might need access it future will be the input filters in case you want to experiment with drivers or do channels adjustments. Make it accessible. Do not forget to do a full sweep of the individual channel after you will be done. You need to make sure that the channels and the filters are working properly. 
 
The last thing. Do buy for yourself a Phase Testers. This is absolutely mandatory tool for your speakers. They call it “Speaker polarity tester”. I use the track #23 from Sheffield Labs 
 
https://www.amazon.com/Sheffield-A2TB-Test-Disc-My/dp/B000V93NKY 
 
Depends what tester you use you might not have a sensitivity of you tester to test at LF. There are some techniques how to deal with it. Anyhow, even a cheap $10 tester for Car Audio is better than to spend half of life to worry where is black and where is red binding posts.


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
02-16-2018 Post does not mapped to Knowledge Tree
anthony
Posts 191
Joined on 08-18-2014

Post #: 132
Post ID: 24697
Reply to: 24696
They are for mA
 Romy the Cat wrote:
You decided to go with mA or are they mV against 1R resistors? I prefer the second approach personally and I feel that I can moderate the quality of resistor and I can’t moderate the quality of the milliampere meter coil. 
 


The ammeters that I have here are quite inexpensive but were one of the few that I could find with a specified coil resistance.  It is 3000ohm.  So I use a 0.6R resistor to set the ammeter scale to 250mA, 0.75R resistor for 200mA and 3R for 50mA at full deflection.  All are quite low values so I think it should be ok.

 Romy the Cat wrote:

You are right now in a very interesting state when you do the internal wiring. The internal wiring. Is to a degree is an art form and it might be very interesting. There are low and high voltages, AC and DC, twisting and not, crossing with minimum angles, some transmission line considerations, signal wires, grounding, approximations, shortening wire paths, maintainability, ease to access and many other considerations that you need to keep in perspective. It is very interesting and creative phases, do not harry to go through with it, spend some time and do it better and methodological. Do the same wiring schema for both R and L amplifiers. When you will be doing the second amp you will find better way to wire it. It is debatable if you want to improve the second one or to the second one as a direct replica of the first one. 


Yes, I built both amplifiers to the same stage (about half finished) and once things got a bit murky regarding the limitations of the wiring I left the second one at a sensible stage and have gone on with the first.  In particular I am hoping that the 6.3V filament wiring for the first and single stages is far enough removed from anything that matters.  I am not sure if it is but that will show up in the measurements.  I have an audio analyser here that I will use to assess and fine-tune the noise levels so hopefully my preparations have been thorough and not to much will need to be altered.
 Romy the Cat wrote:
BTW, did you do it as two identical or you went full-throttle and made it mirroring? 
  

Yes, the amplifiers and the power supplies are both mirrored.

 Romy the Cat wrote:

Also, if everything is works fine then the only part that you might need access it future will be the input filters in case you want to experiment with drivers or do channels adjustments. Make it accessible. Do not forget to do a full sweep of the individual channel after you will be done. You need to make sure that the channels and the filters are working properly. 
  

Yes, the filters are very easy to get to and hopefully relatively easy to alter.  
 Romy the Cat wrote:

The last thing. Do buy for yourself a Phase Testers. This is absolutely mandatory tool for your speakers. They call it “Speaker polarity tester”. I use the track #23 from Sheffield Labs 
  
https://www.amazon.com/Sheffield-A2TB-Test-Disc-My/dp/B000V93NKY 
  
Depends what tester you use you might not have a sensitivity of you tester to test at LF. There are some techniques how to deal with it. Anyhow, even a cheap $10 tester for Car Audio is better than to spend half of life to worry where is black and where is red binding posts.


Thanks Romy, I'll do that.
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