[Cloud]

 Should have just built a four-deck stepped attenuator with values from ~150k down to 10k and been done with it. Hmmm, now thats an interesting thought....

 
i have the same thought, just that i was thinking of socketing a trimmer. when i found the value i like, i will replace the trimmer with a resistor. Cheaper this way i think

 

 

[jdkJake]

A trimmer would work for CL gain at r11, but would not work for OL gain/NFB setting at R13 and R14. Getting two trimmers set to within 1% of each other (which is what you can achieve with resistors) would be pretty difficult. Switching out actual resistors would be far more accurate.

EDIT: Also, finding a trimmer properly sized that would not get you into trouble will also be a challenge.

 

[sachu]

k..finally got around to bringing up the power supplies on both the channels.
 
I upped the rail caps to 6800uF. Pre-reg voltage is at 43V unloaded. Not too bad. 
 
Am not feeling like bringing up the amp boards tonight. The custom panels are coming in tomorrow, so might just do it all at once then.

 

[Jrossel]

Good news!  The boards are in and they look really good.
Alex and team you have really outdone yourselves.  I will be working on
kits for the next few weeks and the boards will be available at
Glassjaraudio.
 
 
Thanks,
 
Jeff

 

[stixx]

Great!
 
That'll be my personal Xmas gift this year...

 

[BK_856er]

My boards are on the way!
  
I ordered all the in-stock Mouser items from the current 1.00j BoM.
  
A number of items were back-ordered, and I'm a bit of a green-horn, so self-identifying appropriate alternatives might be risky.
 
Can anyone help me identify good alternatives for the following?
  
WIMA  MKS2-.1/63/10  Polyester Film Capacitors 63V .1uF 10%
ON Semiconductor  LM317TG  Linear Regulators - Standard 1.5A ADJ 1.2-37V Positive
Fairchild Semiconductor  BC550CBU  Bipolar Small Signal NPN 45V 100mA HFE/800
Nichicon  UPW1H471MHD  50volts 470uF 12.5x20 20% 5LS
Nichicon  UVR1H222MHD  50volts 2200uF 16x35.5 20% 7.5LS  <BOM calls for 10mm lead?>
Nichicon  UVR1H101MPD  50volts 100uF 8x11.5 20% 3.5LS
Nichicon  UVZ1C222MHD  16volts 2200uF 12.5x20 20% 5LS
 
BK

 

[jdkJake]

 
Welcome to the joys of part hunting. You need to search out and find equivalent parts. Look for electrical first and packaging second. Generally, you will find high rated parts are more available (and expensive). Sometimes, the exact opposite is true. Try to stick to a known brand if at all possible. Quality is as important as price.

 

For example, from Mouser:

 

WIMA  MKS2-.1/63/10  Polyester Film Capacitors 63V .1uF 10%

 

   I would suggest the Vishay parts, but they seem to be on backorder as well.

   Did you check TAW Electronics? They usually have WIMA stock on these parts.

   Otherwise, this EPCOS part is available 871-B32529C104K189. Never used them, so, cannot comment on quality

 

ON Semiconductor  LM317TG  Linear Regulators - Standard 1.5A ADJ 1.2-37V Positive

 

  The Fairchild or STMicro will work fine here: 512-LM317T or 511-LM317T I am using the Fairchild parts for both 317 and 337.

 

Fairchild Semiconductor  BC550CBU  Bipolar Small Signal NPN 45V 100mA HFE/800

 

   This will work fine: 512-BC550CTA (different delivery packaging Ammo versus bulk)

 

Nichicon  UPW1H471MHD  50volts 470uF 12.5x20 20% 5LS

Nichicon  UVR1H222MHD  50volts 2200uF 16x35.5 20% 7.5LS  <BOM calls for 10mm lead?>

Nichicon  UVR1H101MPD  50volts 100uF 8x11.5 20% 3.5LS

Nichicon  UVZ1C222MHD  16volts 2200uF 12.5x20 20% 5LS

 

   Mouser now stocks Panasonic FC series (I used FM series where available and FC for the rest, only sourced from Digikey).

   Unfortunately, the 470uf parts are backordered as well.

      667-EEU-FC1H471

      667-EEC-FC1H222

      667-EEU-FC1H101

      667-EEU-FC1C222

      

Spend some time researching the different parts that are available and why they differ. You will learn a lot that will help you in future builds. We are fortunate the internet makes this easy to do.

 

 

    

 

[cobaltmute]

My transformer came in this week instead of last week.  I should have power up in the next few days.

 

[TheShaman]

Quote:

Good news!  The boards are in and they look really good.
Alex and team you have really outdone yourselves.  I will be working on
kits for the next few weeks and the boards will be available at
Glassjaraudio.
 
 
Thanks,
 
Jeff

 

That'll make a great Christmas present indeed!
Jeff, please let us know when you have an estimate of pricing.
 
Would the EHHA RevA serve dual-duty as a preamp as well? Any changes necessary?

 

[BK_856er]

Quote:

 
Welcome to the joys of part hunting. You need to search out and find equivalent parts. Look for electrical first and packaging second. Generally, you will find high rated parts are more available (and expensive). Sometimes, the exact opposite is true. Try to stick to a known brand if at all possible. Quality is as important as price.

 ...

Spend some time researching the different parts that are available and why they differ. You will learn a lot that will help you in future builds. We are fortunate the internet makes this easy to do.

... 

    

Thanks, jk, I appreciate it.  I started to dig into spec sheets/sources/brands yesterday and became pretty overwhelmed with detail and differentiating important from unimportant for a given location.  I'll have another go at it with the leads you mention.  The learning ramp is a steep one.  I definitely don't want to cheap out anywhere and I'm in no real hurry.  From earlier builds, I have given up on trying to collect everything from just one or two orders - too much pressure.  I sourced lead bender tools from TAW last week and had a great experience, so I tried them for the WIMA part....35,000 in stock and 4pcs are on my way gratis...great company to deal with!
 
BK

 

[jdkJake]

Quote:

Thanks, jk, I appreciate it.  ...  
I sourced lead bender tools from TAW last week and had a great experience, so I tried them for the WIMA part....35,000 in stock and 4pcs are on my way gratis...great company to deal with!
 

Your welcome.
 
I too have had a great experience with TAW. Very, very easy to work with and always looking to make things easier and more affordable (i.e. Shipping).
 

 

[jdkJake]

Finally, the casework is done!! (Warning, FAR too many photos coming):
 
Wanted to do something a bit more special with this one. I wanted to give the chance for the tubes to shine (literally) without being too overt. Overall, I am pleased with the way it turned out.
 
This is a Par-Metal 12x12x3 case:
 
 

 
Kind of  tight, so I went vertical with the e12's:
 

 
Spartan back-panel (Thanks to Horio for the idea to back mount the neutriks, I think they look far better that way):
 

 
And the front, featuring "windows" for the tubes with a play on the topology of the amp itself:
 

 
Changed out the LED color, these are actually purple and only 2200mcd to dim it down a bit for night time use. Just enough light:
 

 
Still sounds better than it looks! 

 

 

[sachu]

nicely done Jk..looks like we both had the same idea with regards to the windows..

 
Now you only need to transition over to orthos to make the journey complete lol

 

[cobaltmute]

That's a three inch high ParMetal isn't it? How is the heat? I was going to go the same way bit am worried about heat buildup in the case.

 

[ujamerstand]

The engravings on the windows look great! Congrats on casing it up! Actually, what are you using to side mount the e12s?