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The Christiansen "DG" 300B Amplifier Build Thread - Page 39

post #571 of 631
Thread Starter 
Quote:
Originally Posted by Mihis View Post
 

Hey!

 

I have Goertz cables in my stereo set. I had already forgotten the name:D

 

Awesome thread btw. and really gorgeous piece of gear that you've build!

 

I started listening a lot more with headphones after I moved and realized my room acoustics went south so it got tiring to listen for a longer periods.

Cool.

 

Do you like the wire?

post #572 of 631

I like it:D It transmits sound and it looks nice:D Actually it had reasonable explanation for the shape and not just some weird marketing speech behind it.

 

I haven't tested any other cables on my system, so can't say if they make a different or not.

post #573 of 631

@tom: 

 

I got a potentially weird question for you. 

 

First let me say that my mom really likes plants. The tropical ones that she collects all need a fair amount of humidity. I recently learned that steam is a pretty good sound absorbent medium. 

 

Is it possible to build a giant humidifier and put it along a wall to absorb sound waves AND help my moms plants grow? I realize it would be a pretty big undertaking, but hey, I would be killing two birds with one stone. : ) 

post #574 of 631
Thread Starter 
Quote:
Originally Posted by Tjj226 Angel View Post

@tom: 

I got a potentially weird question for you. 

First let me say that my mom really likes plants. The tropical ones that she collects all need a fair amount of humidity. I recently learned that steam is a pretty good sound absorbent medium. 

Is it possible to build a giant humidifier and put it along a wall to absorb sound waves AND help my moms plants grow? I realize it would be a pretty big undertaking, but hey, I would be killing two birds with one stone. : ) 
Yes.
Move the plants and hi-Fi gear to the bathroom.
Beethoven Symphony No. 6, 1st. movement will be especially enjoyable.
Edited by sceleratus - 11/12/13 at 7:58am
post #575 of 631

Nah, my mom wants me to build her a green house in the spare room. I will vent it and everything. However, I have some special equipment and tools that might make it suitable for a listening room. 

post #576 of 631
Thread Starter 

I can't leave well enough alone.

I just ordered 2 Jensen Transformers JT-11p4-1, Neutrik F-XLR, a couple 24K9's,  and 10 nF caps.

Going to give XLR's a whir again.

 

The DMM measures1.49VAC output from the Gungnir RCA for both RCA and XLR* when a 1kHz tone is playing.  I expected 2V from the RCA and 4V from the XLR.  I’m guessing this is due to the recording level of the 1kHz tone file.

 

*This was with an RCA to XLR cable where Pin 1 and Pin3 on the RCA are tied together.

 

When I put an external input transformer “PVA” Jack sent me, the voltage drops to 0.8 VAC.  When I peg it I get 2.76 V RMS from the O’ Scope.

post #577 of 631
Thread Starter 

Put in some Jensen Line Input Transformers.

Now I can use the Balanced XLR's on my Gungnir.  I got about a 20% boost in power.  Not measured just by feel.  This is just what I needed with my ripped LP's that are recorded at a lower level.

 

post #578 of 631
Thread Starter 

Have a set of Sophia Electric™ Princess Mesh 300B sometime this week.

post #579 of 631
Thread Starter 

There's no free lunch.

This was an expensive experiment.  Distortion.  Lots.

Two days putting it in.  20 minutes reverting back to SE.

Sounds great.  The volume is what it is.

I'm done.

post #580 of 631

Well, there isn't anything clearly wrong with your schematic.

 

I can't say I like the physical implementation much though. You might try to strictly follow this:

 

 

Orange arrows show where the wires should be twisted together right up to the components' pin.

 

I jumpered the caps as suggested by SE. You're still using leds for bias, right ?

post #581 of 631
Thread Starter 
Quote:
Originally Posted by 00940 View Post
 

Well, there isn't anything clearly wrong with your schematic.

 

I can't say I like the physical implementation much though. You might try to strictly follow this:

 

 

Orange arrows show where the wires should be twisted together right up to the components' pin.

 

I jumpered the caps as suggested by SE. You're still using leds for bias, right ?

The components are all board mounted.

ECC88 Pin 9 goes to ground via a string of diodes.

All are board mounted.

 

 

 

 

The input transformers have been replaced with 220nF caps.  (See Schematic Option on Left)

 

post #582 of 631
Quote:
Originally Posted by 00940 View Post

Well, there isn't anything clearly wrong with your schematic.

I can't say I like the physical implementation much though. You might try to strictly follow this:

Orange arrows show where the wires should be twisted together right up to the components' pin.

I jumpered the caps as suggested by SE. You're still using leds for bias, right ?

Why are you taking the can and the shield to the chassis instead of signal ground?

se
post #583 of 631
Quote:
Originally Posted by sceleratus View Post

Do you mean break the grounds between L/R ?

No. In the schematic you showed in the other thread, it had the input transformer AND a 220nF coupling cap. I was suggesting you jumper across the caps, but now it seems that you didn't have those caps in the circuit at the same time you had the transformers. Is that correct?
Quote:
I have not checked the Gungnir outputs.
Is that simply looking for DC voltage on the outputs with a DMM or scope?

Yeah, just look for any DC voltage across pins 2 and 3.

se
post #584 of 631
Thread Starter 

Sorry for all the confusion.  I've run 3 different configurations.

 

1) Jensen Transformers on the Driver board (no caps).  1a) with a POT and RCA inputs.  1b) with XLR and a Goldpoint 4-deck attenuator  (Schema Option)

2) Removed Jensen input transformers from the board and replaced them with Mundorf Silver 220nF Caps.  RCA inputs  (Schema Option)

3) Most recently and briefly added the "outboard" Jensen trans in the diagram intron t of the driver board still with the 220nF caps.

 

I am now listening to configuration number 2 and that's where I'm staying.  It's quiet as a dead church mouse and very musical.  As I type, I'm 4 songs into the Sophia Electric 300B mesh princess.

They are a big step up from the JJ's.

 

I don't see an upside to working on the outboard trans configuration again.  Sure I'd like a little more punch but I don't want to screw up what I have.   There's a lot more source RCA out's than XLR.

I'll probably mung with the meter Steve and get a value on the Gungnir.   Can't take her apart because I have got to get 100 hours on this glass

post #585 of 631
Don't have to take the Gungnir apart. Just measure between pins 2 and 3 on its output jacks.

se
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