[Lil' Knight]

 
 
Obviously the PSU is being loaded severely. Check to make sure the negative rail is not shorted to ground on the amp section.
 
check output MOSFET on the amp section. Check impedances between drain and gate.
 
Also, get him to measure the trim pot setting on the amp board. Make sure it is turned counter clockwise (if its a 1k trimpot, it needs to be at 1k when measured across the outer terminals.)
 
 

What I got from him were:
+ No short between the negative rails and gnd.
+ No short in the MOSFETs.

When the amp is up, he got +16vdc and -40vdc respectively. C4C blew too.

 

[Sathimas]

Hi there, since someone mentioned the bad term "tube rolling" some days ago
it's constantly on my mind ... :-D
 
I prefered the sound of a GE6680 in my SOHA - does anybody know that
tube here and what tube could give a similar sound in the EHHA?

 

[sachu]

Quote:

What I got from him were:
+ No short between the negative rails and gnd.
+ No short in the MOSFETs.

When the amp is up, he got +16vdc and -40vdc respectively. C4C blew too.

lol..i thought you said the negative rail was exhibiting problems. Looks like its the positive rail that is being loaded.
 
Ask him to run the same checks as before. test for shorts between rail and ground. Then check transistors on positive rail, especially Q6 and Q8. RUn a diode check on those two.
 
of course replace C4. Make sure its polarity is not switched around and that it is rated at 50V.
 

 
Quote:

Hi there, since someone mentioned the bad term "tube rolling" some days ago
it's constantly on my mind ... :-D
 
I prefered the sound of a GE6680 in my SOHA - does anybody know that
tube here and what tube could give a similar sound in the EHHA?

Might be a tough task as tube rolling on the EHHA isn't as profound as it is on something like the SOHA or the CTH.

 

[jdkJake]

Assimilation is complete, resistance was futile.... 

 
Okay bk_856er, okay sachu, I finally took the plunge to see what the fuss is all about. 
 
These are Rev1's that I actually received way back in April. Finally got some quality time with them the last couple of days.
 
Nice. VERY Nice.
 
I now understand.
 

 

[BK_856er]

Congrats - it's a sweet pairing for sure!
 
BK
 

 

[foet]

That looks awesome. Love the little windows .
 
Having a slight trouble with my build again. At the last stage of soldering the actual amp boards and preparing for wiring.
After missing some resistors (and having about 5 left who's values are nowhere mentioned in the BOM) - I'm missing components again: Q6, Q7 and CRD1. Are any of these optional maybe? Or did I receive a slightly messed up kit from GJA.
 
Also.. I just figured out I wired P1 wrong looking at people's complete builds. Does the direction matter at all or is it time to pull it and reverse it .

 

[jdkJake]

Thanks.
 
Regarding your build, no those are certainly not optional components. The CRD biases the tubes and Q6/Q7 are at the heart of the VAS section of the amp. So, I would carefully check again.
 
What "leftover" resistors do you have left? Also, which ones did you consider missing?
 
The P1 orientation should be okay, just be aware it will not respond in the manner you would expect.

 

[foet]

I was missing the R1 1MΩ, R30, R31 200kΩ and the R17 (mosfet) 1.5KΩ. I ordered those along with some items I still needed from mouser so it really didn't bother me. I rather bought them and was sure then solder the only ones remaining because they were the only choices left.
 
"pulls out good oldie multi"
 
At the moment I only have the following items left from my kit : the ALPS, the 2 sockets for the tube's, 4 LEDS, the 2 opamps and the resistors. 410K, 120K, 2* 130K, 145K and a 222K Ω.
Also 2 items I cannot identify, they look like the 3 legged transistors only with 2 legs (middle cut away) and the following text on them ; 511 <triangle sign> C513AB and a (P) stamped on the back. Could these be an alternative for the 1N5313 CDR1?

 
As said, all other boards are complete at this point with everything soldered. Since the components for the 2 other boards were in separate labeled bags it made things a bit easier to sort out. I matched (and measured as far as possible) everything soldered so far so I find it strange to have non matching combinations left (i.e. no pairs of resistors but mostly single values).
 
Off course when everything says "Boom" on first power up I'll know I was in error

 

[jdkJake]

Yes, the J511 is a replacement for the 5313 CRD. See back a few pages ~post 1291.

What are the LED's rated?

 

[Navyblue]

Guys I have a question.
 
I am looking for a tube/hybrid preamp (primarily) that will also drive headphones (as a bonus). So transparency and details are most important, and driving power is less so. Which of the EHHA, SOHA II and Bijou would be best for my need? This is subjective but I'd like to hear your personal opinion.
 
Thanks.

 

[foet]

Thanks for the help jdkJake.
 
Okay, how would I align this thing (J511)? There is no indication of poles or direction and Google doesn't directly assist me.
No idea what the led's are rated, my multi doesn't have that option. I can tell you they are blue (at least 3 are - 1 doesn't light up when using diode check). :<

 
Quote:

Yes, the J511 is a replacement for the 5313 CRD. See back a few pages ~post 1291.

What are the LED's rated?

 

 

[iamthecheese]

I have my glassjar kit and a 12x12x3 par metal with extra vent holes coming soon, I have a couple questions about grounding though. I've seen a couple people use a ground loop isolator, is my understanding correct that this gets connected to the ground from the AC socket, and this isolator keeps that ground separate from the star ground? If so, what would be a good isolator to use?
 
 

 

[BK_856er]

Quote:

I have my glassjar kit and a 12x12x3 par metal with extra vent holes coming soon, I have a couple questions about grounding though. I've seen a couple people use a ground loop isolator, is my understanding correct that this gets connected to the ground from the AC socket, and this isolator keeps that ground separate from the star ground? If so, what would be a good isolator to use?
 
 

Nope - typical ground loop breaker goes between star ground and chassis.  AC socket safety ground to chassis is separate/short/not shared with anything else.  I don't know if it's important, but I also took some time to remove internal black anodizing on the par-metal case to get good conductivity between all the panels.
 
BK

 
 

 

[iamthecheese]

Quote:

Nope - typical ground loop breaker goes between star ground and chassis.  AC socket safety ground to chassis is separate/short/not shared with anything else.  I don't know if it's important, but I also took some time to remove internal black anodizing on the par-metal case to get good conductivity between all the panels.
 
BK

 
 

Ah, thanks for the clarification...any suggestions for a ground loop breaker?
 
 

 

[sachu]

Class X or Class Y 250VAC rated 0.1uF capacitor and a 10R/5W wire wound resistor in parallel.