[Ultrainferno]

Quote:

I'm quite intrigued about this amp... How does the Crack w/ Speedball compare with La Figaro 339. Especially regarding HD650.
 
Tx,

 
The 339 is the smoother, warmer sounding and the more tube sounding amp of both. The Crack is faster, clearer and has a better defined bass. Bass depth is better on the 339.
The HD650 is great with both, If you want to clear up the HD650 go for the Crack, if you like it's darkness go for the 339.

 

[.Sup]

I finished building and everything checked out except the resistance to the right RCA connector is 85 (ohms?) compared to 90 like it should be on the left RCA. When listening, the left channel sounds audibly louder, not by much but still enough to perceive it. I also measured from the potentiometer and its still 86. Any ideas?

 

[Beefy]

Quote:

I finished building and everything checked out except the resistance to the right RCA connector is 85 (ohms?) compared to 90 like it should be on the left RCA. When listening, the left channel sounds audibly louder, not by much but still enough to perceive it. I also measured from the potentiometer and its still 86. Any ideas?

 
Yeah, that isn't helpful. You need to tell us exactly what you are measuring - where from, where to, and the correct units.
 
I suspect you are measuring ground to signal, through the pot. In that case, the difference in resistance of 5kohm doesn't make a difference. The pot is a voltage divider, and the absolute resistance doesn't matter.

 

[liamstrain]

Quote:

When listening, the left channel sounds audibly louder, not by much but still enough to perceive it.

 
 
That could easily be a tube issue (triode imbalance on either tube) - if it is mostly noticable at low volumes (or when the volume pot is turned low due to high sensitivity headphones), it could be the Pot ... I don't think a 5kohm difference at the RCA's would cause that. Maybe Doc B will have an idea though.

 

[.Sup]

That could easily be a tube issue (triode imbalance on either tube) - if it is mostly noticable at low volumes (or when the volume pot is turned low due to high sensitivity headphones), it could be the Pot ... I don't think a 5kohm difference at the RCA's would cause that. Maybe Doc B will have an idea though.

The front tube looks like new but I have never seen a tube glow so little, there is only a tiny part glowing. That power tube looks like it was made 50 years ago being very dirty, pins need cleaning and a lot of the metal portion has oxidized. It was difficult to insert it.



The sound is OK though.

 

[liamstrain]

the little input tubes are not a very "glowy" type - that's normal. 

 

[.Sup]

the little input tubes are not a very "glowy" type - that's normal. 

thanks for the info Liam. Could the power tube cause this? All the measurements I took checked out.

 

[Draygonn]

The front tube looks like new but I have never seen a tube glow so little, there is only a tiny part glowing. That power tube looks like it was made 50 years ago being very dirty, pins need cleaning and a lot of the metal portion has oxidized. It was difficult to insert it.

If you are planning on keeping the stock tubes, clean the pins with deoxit. I wouldn't worry about the input tube glowing just a little, that is normal with the tubes I have used.

 

[.Sup]

If you are planning on keeping the stock tubes, clean the pins with deoxit. I wouldn't worry about the input tube glowing just a little, that is normal with the tubes I have used.

Thanks Draygonn. I haven't decided if I will invest in a better tube yet, at this point I'm not even sure if I will install the SpeedBall upgrade even though I have it sitting on my desk. Would really like to remedy the problem first.

 

[liamstrain]

Have you posted on the Bottlehead forum? 

 

[.Sup]

Have you posted on the Bottlehead forum? 

Haven't yet, will do so tomorrow Liam.

 

[.Sup]

Guys before I make a post on the Bottle forum I thought I'd buy a tube just to rule that out. What is a good place to buy a tube suitable for this amp?
thanks

 

[hipcat]

If you haven't read through this thread yet I would say read through it there is some info on tubes here I would also go to the bottlehead forum there is a thread on tube rolling in the crack area and read through it you'll get an idea on what tubes people like. I use ebay alot but I try to buy used tubes, they are cheaper and I havent got a bad tube yet, and you get a feeling for if you like that tube and if it goes bad you won't mind paying more money for a nos tube.

 

[.Sup]

If you haven't read through this thread yet I would say read through it there is some info on tubes here I would also go to the bottlehead forum there is a thread on tube rolling in the crack area and read through it you'll get an idea on what tubes people like. I use ebay alot but I try to buy used tubes, they are cheaper and I havent got a bad tube yet, and you get a feeling for if you like that tube and if it goes bad you won't mind paying more money for a nos tube.

Okay thanks hipcat. Should I look at replacing both tubes?

 

[.Sup]

Hello guys, I just got the tubes and guess what - channels are now balanced! I am so proud of myself right now as this was my first DIY project and I was really thorough when building and refused to admit to myself I could have done something wrong. I am ecstatic right now as I got the tubes a day before I go on vacation till the end of the month and now I will be able to enjoy myself there even more. I am writing slightly under influence because after last night's live Buena Vista Social club concert I am still sobering up but could not wait to thank everybody who offered help here and the Bottlehead family. I just hope tubes are properly tested before shipped in the future as I was unable to listen to the amp for weeks because of the faulty tube. Thank you again!

Will be working on Speedball next month.

On a second thought I might take Speedball with me and work on it on my vacation!