gemini86
Well-known member
If I spent more time recording and less DIY, this preamp would never have happened.
[BUILD] GIX-51X tube preamp
- Thread starter gemini86
- Start date
Help Support GroupDIY Audio Forum:
There is a fantastic set of talks by Rupert Neve from 2007 AES at <http://rupertneve.com/company/notes/>. A real pleasure to listen to all of them, very interesting and lots of nice anecdotes and he talks about lashing together sound systems from scrap for Winston Churchill after the war.
Relevant to this post, this audio track <http://rupertneve.com/wp-content/i/2007-rupertneve-aes-1.mp3> (at minute 3:44 seconds) he speaks directly to the issue of this post, Mr. Neve saying "the question of measuring something or using your ears to listen to it has always been one of the great problems, we all know that you can measure as deeply as you like and it often doesn't co-relate to what you actually hear, we've all got our theories I am sure as to why that should be, but you see...." and he goes on some and he quotes Lord Rayleigh from his book The Theory of Sound "directly or indirectly all questions connected with this subject must come for decision to the ear, as the organ of hearing and from it there can be no appeal." and he also quotes Lord Kelvin "in physical science the first essential step in the direction of learning any subject is to find principals of numerical reckoning and practicable methods for measuring some quality connected with it, I often say that when you can measure what you are speaking about and express it in numbers you know something about it but when you cannot measure it, when you cannot express it in numbers, your knowledge is a meager and unsatisfactory kind it may be the beginning of knowledge but you have scarcely in your thoughts advanced to the state of science". And then Rupert goes on with his thoughts on the matter.
They are fun, there are several hours of them.
b
Relevant to this post, this audio track <http://rupertneve.com/wp-content/i/2007-rupertneve-aes-1.mp3> (at minute 3:44 seconds) he speaks directly to the issue of this post, Mr. Neve saying "the question of measuring something or using your ears to listen to it has always been one of the great problems, we all know that you can measure as deeply as you like and it often doesn't co-relate to what you actually hear, we've all got our theories I am sure as to why that should be, but you see...." and he goes on some and he quotes Lord Rayleigh from his book The Theory of Sound "directly or indirectly all questions connected with this subject must come for decision to the ear, as the organ of hearing and from it there can be no appeal." and he also quotes Lord Kelvin "in physical science the first essential step in the direction of learning any subject is to find principals of numerical reckoning and practicable methods for measuring some quality connected with it, I often say that when you can measure what you are speaking about and express it in numbers you know something about it but when you cannot measure it, when you cannot express it in numbers, your knowledge is a meager and unsatisfactory kind it may be the beginning of knowledge but you have scarcely in your thoughts advanced to the state of science". And then Rupert goes on with his thoughts on the matter.
They are fun, there are several hours of them.
b
mulletchuck said:All this testing, and not a single person has actually used these preamps for recording since they finished their builds? COME ON PEOPLE!!! FOCUS ON WHAT MATTERS!!!!
gemini86
Well-known member
Okay mulletchuck, you asked for it...
it aint pretty, but it's something. Recorded last weekend, here's a rough mixed clip of vocals and electric guitar through the DI jack.
Not my best vocals, I could have done a few dozen more takes...
https://soundcloud.com/gemini86-1/g9-51x-vocal-and-guitar-test
it aint pretty, but it's something. Recorded last weekend, here's a rough mixed clip of vocals and electric guitar through the DI jack.
Not my best vocals, I could have done a few dozen more takes...
https://soundcloud.com/gemini86-1/g9-51x-vocal-and-guitar-test
jandoste
Well-known member
Hey guys,
I am not sure about "C26, C27, C29" I got some 100uF but 35V or 100V... can I use 35...100V or I need to get more voltage?
Thanks
I am not sure about "C26, C27, C29" I got some 100uF but 35V or 100V... can I use 35...100V or I need to get more voltage
?Thanks
gemini86
Well-known member
C26, 27 are both filtering the +-24V rails, C29 the 16V rail, so 35V is fine on all those.
kvothe
Well-known member
- Joined
- Feb 5, 2013
- Messages
- 87
Hello everyone,
I have ordered some kits and now have questions concerning different transformer options and their impact on the sound. I already read about the different low frequency rolloffs pointed out by bruce0, but can someone comment further on the sound of some of the combinations? (difference between prices are huge) Anybody used the ea2622 on input? I will be shopping at classicapi soon, so I could buy them there.
input is much aprreciated and thank´s a lot for this awesome project!
I have ordered some kits and now have questions concerning different transformer options and their impact on the sound. I already read about the different low frequency rolloffs pointed out by bruce0, but can someone comment further on the sound of some of the combinations? (difference between prices are huge) Anybody used the ea2622 on input? I will be shopping at classicapi soon, so I could buy them there.
input is much aprreciated and thank´s a lot for this awesome project!
mulletchuck
Well-known member
I would really love to build a pair of these, but no one has posted clips of what they sound like on a bunch of sources (drums, guitars, pianos, horns, vox, etc). Who's actually used these guys in the studio, what did you use them on, and how were the results? I'm only bringing this up because my 2 51x chassis are full, so if i were to put these guys into regular use, i'd need to get a 3rd chassis and that opens a completely new can of worms lol
gemini86
Well-known member
Once I build a road lunch box, I'll be handing mine over to a local studio owner. That will take a while though.
jandoste
Well-known member
Thanks Rodney!
gemini86 said:
gemini86
Well-known member
gemini86 said:
mulletchuck
Well-known member
that sounds pretty good. What's it sound like without the reverb/compression?
Let's talk about that DIY U47!!! who's build is that and what capsule?
Let's talk about that DIY U47!!! who's build is that and what capsule?
jandoste
Well-known member
My bad! :'(
How I get it I don't remember but I received mouser package this morning...
http://fr.mouser.com/Search/ProductDetail.aspx?R=CK2368virtualkey12200000virtualkey105-2454
and this one is non shorting So I'm not sure if it will work?
Any advice?
Thanks
How I get it I don't remember but I received mouser package this morning...
http://fr.mouser.com/Search/ProductDetail.aspx?R=CK2368virtualkey12200000virtualkey105-2454
and this one is non shorting
So I'm not sure if it will work?Any advice?
Thanks
gemini86 said:
gemini86
Well-known member
Bruce was having clicking issues with his using non shorting switches. I haven't experienced issues. I haven't looked into it a ton to see for sure but it seems that clicks should only happen on the first four settings. In those positions the switch is attenuating v1b's output, after that it's attenuating the feedback signal to increase gain. There's no DC present on the switch.
Funny you should mention this, I just posted on the G9 thread that this problem was because of microphonic tubes (in 2 out of 4 preamps), and now that those tubes are swapped out, and the preamps are bolted down in the rack, the clicks and pops are gone.gemini86 said:
So I am using BBM switches on 3 of the preamps and leaving them that way, they are not noticeably different from each other. Changing gain sounds the same on both, and it reasonably quiet (no pops).
gemini86
Well-known member
Good to know I'm not just crazy! haha...
Seriously that had me stumped.
Seriously that had me stumped.
gemini86
Well-known member
It's all good.
I'm currently using some old GE tubes from a Hammond organ. Took a while to find a good quiet one for V1.
I'm currently using some old GE tubes from a Hammond organ. Took a while to find a good quiet one for V1.
Was putting a cart together last night from mouser and I ran into some questions with the B.O.M. so here we go...
I need a lil bit more clarification on which capacitors to select especially the ones that don't specify WIMA. Many choices pop up so I use the filter to filter the choices and then I'm still left with many to choose from and for someone like me that is too confusing.
Example: the first CAP says "1000uF/35V 5mm LS Aluminum Electrolytic. Since there is no brand specified here I go to passive components, capacitors, electrolytic, then I select the capacitance filter and the noted value, the voltage filter and the noted value, then the Lead Spacing noted value. But i'm still left with 91 possibles after that. I try to shoot for 5-6 possibles
Again I'm having this issue with ALL the caps that are not specified WIMA or just has a value by it and nothing else, so if I could get some assistance on this issue it would help a great deal.
For the CAPS labeled WIMA I noticed that there are options for the LS. Is there any importance to this at all other than price from what I see?
--CAPS--
1000uF/35V 1 "C504" 5mm LS Aluminum Electrolytic
100nF 6 "C12, C30, C31, C32, C33, C505, 5mm LS 63V WIMA
100nF 3 "C501, C502","RODNEY CAP" 2.5mm LS 63V WIMA
100nF 2 "C506","FILTER MOD" 7.5/10mm LS 250V Ceramic
100u 3 "C26, C27, C29"
10n 2 "C8, C9" 5mm LS WIMA 63V
10u /63V 1 "C7" 22.5/27.5mm LS FILM
10uF/250V 3 "C25, C503, C507" 5mm LS Aluminum Electrolytic
1u5 1 "C4" (mouser)505-MKS41.5/250/10
220n 2 "C2, C10" 5/7.5/10mm LS WIMA 250V
470n/250V 1 "C3" 10/15mm LS WIMA 250V
470n 1 "C5" 5/7.5/10mm LS WIMA 250V
470u 1 "C11"
47u 1 "C28"
4u7 1 "C13" 22.5/27.5mm LS WIMA 250V
68p 1 "C6"
Below are the rest of the parts that I could not find on mouser:
50K-log 1 "RV1" Alpha RV16AF-41-15R1-A50K
1.2mH 1 "L503" (mouser)562-RL187-122J-RC OR EQUIVALENT
1N4004 3 "D2, D7, D502" (this part had options that I wasn't sure to about)
Once I get the needed assistance I will submit my BOM for review here in the thread and make my Mouser cart available to everyone so for those like me, there is a simple few clicks and off to checkout.
Thanks in advance
G
I need a lil bit more clarification on which capacitors to select especially the ones that don't specify WIMA. Many choices pop up so I use the filter to filter the choices and then I'm still left with many to choose from and for someone like me that is too confusing.
Example: the first CAP says "1000uF/35V 5mm LS Aluminum Electrolytic. Since there is no brand specified here I go to passive components, capacitors, electrolytic, then I select the capacitance filter and the noted value, the voltage filter and the noted value, then the Lead Spacing noted value. But i'm still left with 91 possibles after that. I try to shoot for 5-6 possibles
Again I'm having this issue with ALL the caps that are not specified WIMA or just has a value by it and nothing else, so if I could get some assistance on this issue it would help a great deal.
For the CAPS labeled WIMA I noticed that there are options for the LS. Is there any importance to this at all other than price from what I see?
--CAPS--
1000uF/35V 1 "C504" 5mm LS Aluminum Electrolytic
100nF 6 "C12, C30, C31, C32, C33, C505, 5mm LS 63V WIMA
100nF 3 "C501, C502","RODNEY CAP" 2.5mm LS 63V WIMA
100nF 2 "C506","FILTER MOD" 7.5/10mm LS 250V Ceramic
100u 3 "C26, C27, C29"
10n 2 "C8, C9" 5mm LS WIMA 63V
10u /63V 1 "C7" 22.5/27.5mm LS FILM
10uF/250V 3 "C25, C503, C507" 5mm LS Aluminum Electrolytic
1u5 1 "C4" (mouser)505-MKS41.5/250/10
220n 2 "C2, C10" 5/7.5/10mm LS WIMA 250V
470n/250V 1 "C3" 10/15mm LS WIMA 250V
470n 1 "C5" 5/7.5/10mm LS WIMA 250V
470u 1 "C11"
47u 1 "C28"
4u7 1 "C13" 22.5/27.5mm LS WIMA 250V
68p 1 "C6"
Below are the rest of the parts that I could not find on mouser:
50K-log 1 "RV1" Alpha RV16AF-41-15R1-A50K
1.2mH 1 "L503" (mouser)562-RL187-122J-RC OR EQUIVALENT
1N4004 3 "D2, D7, D502" (this part had options that I wasn't sure to about)
Once I get the needed assistance I will submit my BOM for review here in the thread and make my Mouser cart available to everyone so for those like me, there is a simple few clicks and off to checkout.
Thanks in advance
G
gemini86
Well-known member
the electrolytics are pulling a really light duty here... the voltage they're receiving is already low ripple, they're just there to reduce cross-talk between modules and add some local stabilization. I use either panasonic or nichicon. After you've filtered down to the specifics noted on the BOM, just choose an inexpensive one.
The pot isn't available at mouser. I got mine from mammoth electronics: http://www.mammothelectronics.com/RV16AF-41-15R1-A-p/210-100-a.htm. You don't HAVE to use that pot, any 16-24mm pot with solder lugs will fit in the space, but you'll need to hand-wire it to the board with short leads.
The inductor is a typo... my bad, I'll fix it. This is the correct part: http://www.mouser.com/ProductDetail/Bourns/RL187-122J-RC/?qs=%2fha2pyFadujgImkQujR83nj3U1cRlrXUQG8gC2LJipSQenDdgLZDWg%3d%3d
The 1n4004 is easy, just make sure it's a through hole part. This one is in stock, it's cheap and there are 228 thousand available.
The pot isn't available at mouser. I got mine from mammoth electronics: http://www.mammothelectronics.com/RV16AF-41-15R1-A-p/210-100-a.htm. You don't HAVE to use that pot, any 16-24mm pot with solder lugs will fit in the space, but you'll need to hand-wire it to the board with short leads.
The inductor is a typo... my bad, I'll fix it. This is the correct part: http://www.mouser.com/ProductDetail/Bourns/RL187-122J-RC/?qs=%2fha2pyFadujgImkQujR83nj3U1cRlrXUQG8gC2LJipSQenDdgLZDWg%3d%3d
The 1n4004 is easy, just make sure it's a through hole part. This one is in stock, it's cheap and there are 228 thousand available.
