saint gillis

Re: D-LA2A Support Thread
« Reply #1860 on: September 13, 2018, 06:03:42 PM »




Awesome! Do you use both hands to turn the gain knobs?


Re: D-LA2A Support Thread
« Reply #1861 on: September 13, 2018, 10:03:06 PM »
Awesome! Do you use both hands to turn the gain knobs?

LOL ::)
www.kontrast.in - I make websites and stores online.

Rlucas41

Re: D-LA2A Support Thread
« Reply #1862 on: September 14, 2018, 01:16:20 PM »
Hi Rlucas41

I never created a cart (s) since I bought the components little by little as money was flowing. I created and used this Excel BOM for the three units that I built so far, is not a cart per se but it contains all the mouser part numbers, you just can copy and paste, it's very complete with prices and everything (is not only the Mouser stuff but the complete BOM), It should be pretty close, I don't remember errors on it but be careful,  I'll leave this link a couple of weeks, I hope that helps.



https://www.dropbox.com/s/xvr7nroz63k0wg3/dual%20la2a%20marco%20bom.xlsx?dl=0

Cheers

Marco


Marco, Thank you very much!

Kindest regards,
Robert

JW

Re: D-LA2A Support Thread
« Reply #1863 on: September 25, 2018, 04:08:57 PM »
I'm curious what portions of the calibration I need to do again if I replace V1

(I went from a pair of 5751 tubes to two 12ax7's for V1 on both channels)

alexc

Re: D-LA2A Support Thread
« Reply #1864 on: September 26, 2018, 03:22:01 AM »
Very, very nice   :)   Loving  the mci meters,  no doubt! I love my ones for sure.
I ping therefore I am

cdeboda

Re: D-LA2A Support Thread
« Reply #1865 on: October 13, 2018, 09:55:47 PM »
Never got around to it so figured I'd do it now. Here are the pictures of my finished D-LA2A. She's a magnificent beast, for sure.

cdeboda

Re: D-LA2A Support Thread
« Reply #1866 on: October 13, 2018, 10:01:03 PM »
Some insides:

cdeboda

Re: D-LA2A Support Thread
« Reply #1867 on: October 13, 2018, 10:02:46 PM »
Some more guts and gore:

cdeboda

Re: D-LA2A Support Thread
« Reply #1868 on: October 13, 2018, 10:03:26 PM »
And finally, insides close up:

JW

Re: D-LA2A Support Thread
« Reply #1869 on: November 09, 2018, 06:03:30 PM »
Can I bump my last question a few posts back.

When replacing V1, do I need to re do the full calibration or just part of it?


[silent:arts]

Re: D-LA2A Support Thread
« Reply #1870 on: November 10, 2018, 02:06:01 AM »
When replacing V1, do I need to re do the full calibration or just part of it?
Nothing to calibrate with V1.

JW

Re: D-LA2A Support Thread
« Reply #1871 on: November 10, 2018, 11:40:41 AM »
Really? I don't even have to re do the stereo balance calibration? Sweet.  (I'm going 5751 tubes to 12AX7)

ron_swanson

Re: D-LA2A Support Thread
« Reply #1872 on: December 11, 2018, 11:35:01 AM »
Hi all,

First, apologies in advance for what may be noob questions.  First post of probably many going forward here.   

I've built a number of 1176 compressors and a couple of Pultec EQ's and done some guitar amp work over the years, but this is my first 'non-kit-in-a-box with full instructions build', so trying to learn as much as I can while doing as much detective (reading including most if not all of the pages within this thread) and as much homework as possible before asking questions. 

With that said... I'm well into my build of this silent:arts D-LA2A build...

Two questions:

1.) There's what looks like an indication for a diode printed on the PCB board sandwiched in-between the top of the relays and the audio input / output headers that I can't seem to correlate to the schematic or the parts list, nor does there seem to be any indication of what component is expected like other components are elsewhere indicated on the PCB.   Am I missing something on the schematic?  The parts list? Maybe a test point?  Something that a more experienced builder would know intuitively?

2.) My enclosure (Collective Cases) includes a 'on' power description as well as a hole for a power indictor light on the front panel for what looks like it would have been made for a 6.3VAC Fender type guitar amp socket and indicator lamp .   If so, in the tube guitar amp circuits I have seen,  it appears that power for this light usually comes from the tube heater power.   Is it ok to source the power for this lamp from one of the other heater lines or is that a bad idea?   If bad, what would be best practice in this case?     I'm using silent:arts PSU.

Thanks in advance!

Greg

Re: D-LA2A Support Thread
« Reply #1873 on: December 11, 2018, 03:31:31 PM »
Hi Greg,

1) This is a flyback diode for the coil in the relay.  https://en.m.wikipedia.org/wiki/Flyback_diode

cheers
« Last Edit: December 11, 2018, 03:35:46 PM by rock soderstrom »

[silent:arts]

Re: D-LA2A Support Thread
« Reply #1874 on: December 11, 2018, 03:39:26 PM »
1) D101, D102, D201 & D202 in the schematic, 1N4148

ron_swanson

Re: D-LA2A Support Thread
« Reply #1875 on: December 12, 2018, 09:34:18 AM »
Hi Greg,

1) This is a flyback diode for the coil in the relay.  https://en.m.wikipedia.org/wiki/Flyback_diode

cheers

Excellent!  Thanks for the link, rock soderstrom!


1) D101, D102, D201 & D202 in the schematic, 1N4148

Ah, now I see...  hidden in plain sight.  Also thrown off by the N14141 --> N14148 notation on the BOM. 

Thanks Volker!

No thoughts on powering the 6.3VAC power indicator lamp using one of the heater power supplies?

andyfromdenver

Re: D-LA2A Support Thread
« Reply #1876 on: December 14, 2018, 01:09:49 PM »

No thoughts on powering the 6.3VAC power indicator lamp using one of the heater power supplies?

You can tackle this one  ;D
Assess your Power Transformer (PT) heater current rating.
Assess the total current draw from the tubes heaters (data sheets).
Assess the current draw of a #47 bulb (150mA).
If you're within the handling, you can use it.

Best wishes,
Andrew
2018 current fav movie: Black Panther
2018 current fav book: Foundation ( I. Asimov)
1997-2018 fav artist: Erik Satie

ron_swanson

Re: D-LA2A Support Thread
« Reply #1877 on: December 17, 2018, 09:57:01 AM »
You can tackle this one  ;D
Assess your Power Transformer (PT) heater current rating.
Assess the total current draw from the tubes heaters (data sheets).
Assess the current draw of a #47 bulb (150mA).
If you're within the handling, you can use it.

Best wishes,
Andrew

Thanks Andrew!

Assuming a 2A PSU spec, it looks like I would be slightly under the PSU specs...

PART       QTY   Ma         A      SUB AMP TOTAL
12AX7   2   300   0.3        0.6
12BH7   1   600   0.6        0.6
6AQ5A    1   450   0.45     0.45
#47           1   150   0.15   0.15
            
                 TOTAL AMPS    1.8A

To be more clear, my question was meant to check if anyone thought adding a lamp to the heater power supply will cause any unexpected issues such as noise or would that be pushing the PSU too close to its specs?

Cheers,
Greg

Rlucas41

Re: D-LA2A Support Thread
« Reply #1878 on: January 08, 2019, 09:57:51 PM »
Opinions please... how important is it to buy a “matched” pair of T4B’s for use in stereo mode?

[silent:arts]

Re: D-LA2A Support Thread
« Reply #1879 on: January 09, 2019, 02:34:36 AM »
My original UREI T4Bs are not matched.


 

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