inputoutput

another [silent:arts] LA-2a New
« on: March 13, 2009, 04:54:58 AM »
very happy now!  ho hey, this was a fun build!! Big thanks to the always generous [Silent:arts].

Input iron switch between 1:1 (sowter 3575) for normal compression, and 1:9.1 (sowter 1009) for harder compression and pre-amp use. Output iron Sowter 1010 (similar to UTC A24)  -  Three-step switch on the (totally unnecessary) limiter/compression option. Added an 6K resistor there. Can hear some difference in the sound when I crunch the input level. Maybe later I´ll try to add some side-chaining features on this switch instead or something. donno yet.

Will continue to experiment with different kinds of ecc83 tubes. They do certainly play a big part in the sound and how much unwanted noise that comes out of this thing.  At the moment I´m using Golden-dragon tubes, They gave the best noise-floor result -75dBu.

most of the knobs and lamps are bought on auctions throughout the years. The meter is from ebay, but a chopped up a new VU meter and squeezed it in there with a new homemadepaper-front.  Other than that, nothing new here.





The output-level is too loud. Has anybody clamped the output-pins with a resistor....  ?

-----------


LATE EDIT :   CJs tips on how to adjust the boards for 12AY7 is a HIGHLY recommended mod.  Now I use it all the time, and the 1:10 input transformer actually makes sense

Good shielded cables are also important, as always
« Last Edit: October 16, 2009, 07:48:47 AM by inputoutput »


Kingston

Re: another [silent:arts] LA-2a
« Reply #1 on: March 13, 2009, 05:00:11 AM »
The output-level is too loud. Has anybody clamped the output-pins with a resistor.... will I create some impedance issues by doing this ?

There's an easier fix. Change the 100K output volume pot to 25K.

As you've probably already noticed, you only really need the first quarter of the 100K in any modern studio I/O situation.

inputoutput

Re: another [silent:arts] LA-2a
« Reply #2 on: March 13, 2009, 05:06:07 AM »
You mean the gain pot? (the silent:arts mod)+ a 75K.  yes, I have already done that, but I would like to lower the volume even more.

« Last Edit: March 13, 2009, 05:12:20 AM by inputoutput »

alexc

Re: another [silent:arts] LA-2a
« Reply #3 on: March 13, 2009, 05:47:00 AM »
What a beauty!

Nicely done in vintage black.

Congrats
I ping therefore I am

Kingston

Re: another [silent:arts] LA-2a
« Reply #4 on: March 13, 2009, 06:25:43 AM »
You mean the gain pot? (the silent:arts mod)+ a 75K.  yes, I have already done that, but I would like to lower the volume even more.

You could use a balanced T-pad directly on the XLR output, after the transformer.

rob_gould

Re: another [silent:arts] LA-2a
« Reply #5 on: March 13, 2009, 07:49:51 AM »

Great build!

Just need to design a case for mine now, and this is great inspiration.

Did you put the power transformer outside the box for noise reasons, or purely because it wouldn't fit inside?


trancedental

Re: another [silent:arts] LA-2a
« Reply #6 on: March 13, 2009, 08:13:12 AM »
 ;D Nice looking build although it remind me of grandmothers kitchen range / stove when I was a kid! 8)
« Last Edit: March 13, 2009, 08:16:24 AM by trancedental »

inputoutput

Re: another [silent:arts] LA-2a
« Reply #7 on: March 13, 2009, 09:32:09 AM »
Did you put the power transformer outside the box for noise reasons, or purely because it wouldn't fit inside?

both

bernbrue

Re: another [silent:arts] LA-2a
« Reply #8 on: March 13, 2009, 01:05:03 PM »
Very nice built. Volkers board is so straight forward. I really enjoyed building this excellent compressor. It has such a unique sound and vocals are somehow "warmly embraced" by this compressor. Lovely. Congratulations !!
regards
Bernd

Bluzzi

Re: another [silent:arts] LA-2a
« Reply #9 on: March 13, 2009, 02:42:20 PM »
Replace V1 with 12AY7 for slightly lower gain and smoother sound. Replace R9 and R13 with 100k. I have these on my 2 LA2As and although I haven't changed the gain pot down to 25k yet it helped tame the volume enough. I imagine using the 25k pot would complete bringing the gain down to a more practical level.

On my first LA2A I had original values and tubes but I liked it more after the mod.

Jim


Re: another [silent:arts] LA-2a
« Reply #10 on: March 13, 2009, 02:53:53 PM »
Nice. The case looks awesome.

I'm doing eight 1290's in a case...and was thinking about doing the same with the toroid.
« Last Edit: March 13, 2009, 02:55:28 PM by desol »

kato

Re: another [silent:arts] LA-2a
« Reply #11 on: March 13, 2009, 08:09:39 PM »

Nice knobs!

Never heard of the 1:9 input option. But I like the idea of mic --> LA2  --> record.

Is there info on this mod? or something you came up with. Any other component changes required on the input?

inputoutput

Re: another [silent:arts] LA-2a
« Reply #12 on: March 14, 2009, 05:11:23 AM »

Nice knobs!

Never heard of the 1:9 input option. But I like the idea of mic --> LA2  --> record.

Is there info on this mod? or something you came up with. Any other component changes required on the input?

nah, depends on how much level you want coming out of the inputtranny. No extra components here. Just  a relay based switch - going to two relays for left-right.  To test out different input transformers is really interesting on tube-equipment. With the input transformer switch -the unit acts as two different compressors. I thought that I would probably never use the "Krunsj" mode except maybe on drums and bass etc. But it actually does terrific things to vocals and all kinds of instruments.  I haven´t seen it done on any other DIY project, but I am certainly gonna include an "iron switch" on upcoming projects too. It is easy to make, you just have to figure out the wiring to and from the transformers.

creal

Re: another [silent:arts] LA-2a
« Reply #13 on: March 14, 2009, 05:59:15 AM »
woow, i like you frontpanel.

you're TX switch mods looks interesting ;D

[silent:arts]

Re: another [silent:arts] LA-2a
« Reply #14 on: March 14, 2009, 06:41:25 AM »
wow, very nice build :) :) :)

and yes, the ECC83 in the output stage is very important for noise etc.
take the best one there

deuce42

Re: another [silent:arts] LA-2a
« Reply #15 on: March 14, 2009, 01:13:05 PM »
Looks fantastic! Uber vintage:)

An Iron switch is such a clever idea. I wish I thought of it too.

inputoutput

Re: another [silent:arts] LA-2a
« Reply #16 on: March 15, 2009, 05:45:23 PM »
thanks!

a PM670 coming up soon with almost the same look  :)

VoiceOverMike

Re: another [silent:arts] LA-2a
« Reply #17 on: March 15, 2009, 06:22:41 PM »
OUTSTANDING!

Bluzzi

Re: another [silent:arts] LA-2a
« Reply #18 on: March 15, 2009, 08:03:42 PM »
Yes, I forgot to say, loved the look. HAM Radio almost.

Jim

Re: another [silent:arts] LA-2a
« Reply #19 on: March 15, 2009, 10:53:15 PM »
Well I hate to pick out such a small detail in that awesome build but... where'd you get the knobs? Very cool look!


 

Related Topics

  Subject / Started by Replies Last post
14 Replies
6219 Views
Last post November 23, 2007, 02:25:45 PM
by r0ck1r0ck2
2 Replies
1145 Views
Last post April 25, 2005, 02:54:15 AM
by gyraf
5 Replies
2205 Views
Last post November 19, 2004, 07:56:31 PM
by volki
48 Replies
35292 Views
Last post May 25, 2017, 09:46:05 PM
by mattmartin831