NewYorkDave 2 bottle / pictures

[Freddy G]

Hi All,
Looking back at 2006, the NewYorkDave 2 bottle mic amp was my main DIY project. I've made some very nice recordings with it, and everyone who has tried it really likes it too.
Here are some pics:
http://www.box.net/public/bfkl0a4q0y
http://www.box.net/public/evqjp76n78
http://www.box.net/public/imlf6z64xu
http://www.box.net/public/qcdztdx182
http://www.box.net/public/nii8yl8u7j

Input transformers are Lundahl 1636 amorphous core ( 1:10)
Output iron is Edcor 15k:600
I got the big Weston meters from Dave (soundguy)
The illuminated pushbuttons on the front panel control omron relays for pad, phase and phantom power.
Output attenuator is an Elma switch wired as a 12 step 600 ohm bridged-T attenuator.
I'm putting together 24 step Elma switches for the gain control but for the moment I have pots installed.
Front panel from Front Panel Express.
Enclosure from Par-Metal.

Here is a sound clip of a recording using this preamp. The recording was done at our company bar where just about every Saturday night employees go up on the stage and perform music, do a comic skit or whatever they want to do. It's usually great fun!
Anyway, on this night a bunch of the employees got a band together and blew the roof off! One side of the NYD preamp was used on the bass guitar DI and the other side was violin DI.
http://www.box.net/public/jouzbxe8em

Thanks to all who helped, especially NewYorkDave!
Happy New Year :sam:
Freddy

 

[laitue5]

Wow :thumb:

 

[Emperor-TK]

A thing of beauty....

-Chris

 

[Greg]

Nice piece of work... :thumb:

 

[tony dB]

superwork! :thumb:

can't play the music unfortunately, everytime I try it makes IE crash... will try later.

 

[matta]

Freddy,

All I can say is DAMN! That is one FINE piece of gear. The workmanship and attention to detail is amazing. Not heard the clip yet, but if it looks anything like it sounds, well, wow!

Cheers

Matt

 

[mrc]

Great sounding DI's, as well as a kickass band.
mrc

 

[kevinc]

Awesome job, Fred!!

 

[tommypiper]

Hi Freddy, great job.

Did you wire your meters off the output transformers?

What are all those big honking caps?

Edit: where did you get that interior silver panel? Is it alum or steel?

cheers!

 

[Freddy G]

Thanks everybody!
Tommypiper:
good questions....my intention was to wire the output to the meters after the attenuator but right now the meter reflects what's going on before the output attenuator. I want to change that.
All those big honking caps are Solens.
I use them whenever I have the space.
Freddy

 

[hejsan]

Hi, great work!

Solens? I keep seing these big black caps in pics here, are they some kind of crossover film caps that people use to get big uF values in film?
Where to get?

Thanks,
hejsan

 

[louder]

alo
i get them at banzaieffects.com
best regards
pedro

 

[Freddy G]

hejsan,
the largest solen cap in the preamp is 22uf. If you notice the only electrolytic on the turret strips is a 47uf. I actually thought about using solen 47 uf but there was not really enough room....the thing was almost as big as a pop can!
I not even sure if there is a real benefit in using film caps everywhere, maybe only certain places....I don't know.
Yes , I admit that sometimes I'm totally guilty of "audiofoolery" :green: haha.
My thinking is this, if you're not sure, just throw lots of money at it! It won't hurt anything other than my wallet
Freddy

 

[Kingston]

oh dear that layout, and everything about it is so much better than on my two channel 2-bottle. :shock:

How did the noise performance end up like?

Funny you ended up with those amorphous core lundahls. A tube DIY'er friend of mine particularly advised against them (can't remember the reason now). Any zobel network on them?

 

[Freddy G]

Kingston,
thanks! I posted a jpeg of my layout in the original NYD one bottle thread. I'll send it to you if you want.
Noise performance is very good, I have not even bothered to measure it because I can't hear it :green:
Maybe I'll measure it today.....can you give me an idea how it should be measured?
No problem with the Lundahls :wink:
No Zobel but Kevin Carter (Lundahl USA) advised me to use a 200k impedence defining resistor before the transformer.
cheers,
Freddy :sam:

 

[Kingston]

I think I saw the layout as work in progress in that other thread, but it looks like a much more robust design now that it's finished, with all the gadgetry.

Measuring noise performance? I'm probably the wrong guy to ask about this, but I just terminate inputs and route the outputs to my RME soundcard, and that into a software FFT plugin (spectrogram). I used it for troubleshooting initially. It shows the ground loops and noise floor nicely, and can be used to select the best tubes.

If you can't hear the noise, you probably needn't bother. My layout was a far cry from yours so noise (ground loops in fact) was initially less than ideal.

 

[Freddy G]

hi kingston,
ok, i measured like you said and when i do a freq analysis, 60 hz is sitting at -103.9 db, 120hz at -122.4db, 180hz at -109.3db and then all the higher harmonics just get progressively quieter.
Freddy :sam:

 

[raysolinski]

[quote author="Freddy G"]Kingston,
thanks! I posted a jpeg of my layout in the original NYD one bottle thread. I'll send it to you if you want.
Noise performance is very good, I have not even bothered to measure it because I can't hear it :green:
Maybe I'll measure it today.....can you give me an idea how it should be measured?
No problem with the Lundahls :wink:
No Zobel but Kevin Carter (Lundahl USA) advised me to use a 200k impedence defining resistor before the transformer.
cheers,
Freddy :sam:[/quote]

Freddy,
200k BEFORE the transformer?...or across the secondary so the input impedance is reflected as 2k ? I never heard of a terminating resistor before the primary..but then again..I'm usually wrong..just ask my wife :green:

Cheers,
Ray

 

[Freddy G]

Ray,
Yes, you are absolutely correct....200k terminating the secondary
I had to dig up my pcb artwork to check.
Sometimes I wonder how I manage to tie my shoes in the morning :wink:
Freddy

edit- I don't even wear shoes with laces! you can see me bluntstones in one of the photos! :grin:

 

[solder_city]

connect a 150 or 200 ohm resistor across the input trans primary. measure the noise level at preamp output. divide noise level by the gain of the preamp to give 'equivalent input noise' figure. for instance if noise is -60dbu and preamp gain is 60db, ein is -120dbu.

to really do it right the noise must be measured within a specific bandwidth. otherwise the noise level will 'look' worse than it really is. nyd and paul stamler had a long discussion about this in a thread on the drawing board, dont remember the name of the thread at the moment