First Build! Questions

[TurbOSquiD77]

Hello everyone,

Finished a stock Crack last weekend, was a great experience! Pics soon!

Stock configuration passed all resistance and voltage checks, and sounded great. Put 6 hours on her then installed Speedball.
Speedball passed all checks as well, and sounds wonderful.
Rolled a 1962 Phillips Miniwatt ECC82, and Svetlana 6AS7G/6H13C in and sounds great as well


I do notice that after installing the Speedball, the input tube flashes very bright, and then settles down to a very dim glow for the remainder of my listening session. I've done a little searching on this, but would like to ask for your opinions on my situation as well. I cannot confirm this happens with the stock input tube, but it didn't happen when the speedball wasn't installed. I will be able to test the stock tube when I am home later this evening. Anyways, is this normal/okay?

Is it normal that these tubes do not glow as bright as say a 6922? Wish they glowed bright all the time like when the input tube flashes at power on hah! I really would like to have a strong glow to my setup, but I know I can't always have my cake and eat it too. Darn cake. Unless there's a way! Lights underneath?

My volume pot is pretty touchy. Maybe a 3/4" inch turn from 0 will get me decent volume. Normal? Beyer T1.2 600 ohm btw.

When my phone is near the Crack, maybe 0-2 ft away, I hear faint static interference. Cool! Kind of. Same issue while on cellular, and wifi, didn't try airplane mode though.


I'd just like to have some input, if you could, before I keep listening/powering on and off.


Overall, I've more than enjoyed the experience of building my first amp. I have no doubt that I will be modding the Crack, or grabbing a Crack-a-two-a to mod. Lovin' it!

Thank you much!

~Turbo

[Chris65]

Certain tubes do flash when powered on, Mullard tubes are well known for this & is normal. Do a web search for 'Mullard tube flash'.
Philips owned Mullard, so quite possible you have a Mullard produced tube.

There is no 'stock' input tube, BH supplies various types as they obtain stocks including new production & new old stock.
Tube glow varies depending on the tube type, manufacturer, circuit used, etc

[TurbOSquiD77]

Got it. It's probably just the tube then, because the (I'll refer to it as the stock tube because I have no idea what it is! lol) stock tube does not flash on power up.

I figure the volume behavior is due to the stock volume pot. Time to upgrade

Not sure about my phone creating interference, however.

Thanks!

[Jeb Jeb]

Hi TurbOSquiD,

If you find you have too little usable range on your volume control check out No.3 on the Crack FAQ page   http://bottlehead.com/smf/index.php?topic=4295.0

It's just a cheap & simple mod, which involves adding a few resistors.  I did this recently (at the same time as I added in a different pot) and found it very worthwhile - allowing me to set the volume with greater accuracy and much less chance of blowing my head off with accidental high volume

[TurbOSquiD77]

Got it, thanks Jeb Jeb. Would this mod have as much of an affect on performance without a high(er) quality pot? I'm guessing so, just checkin!

[Jeb Jeb]

Yes, padding the pot with the resistors didn't affect sound quality, it just allowed me more usable range on the dial.  Prior to adding them in, for my preferred volume I was about where you seem to be on the dial (about 8 or 9 O'Clock).  Now around 11 or 12 O'Clock is good - depending on the music and how I'm feeling.

I thought I would just mention it since only replacing the pot might not necessarily solve the issue of high volume that you are having - it didn't for me.

Some people have mentioned a slight channel imbalance at lower volumes with the stock pot, but apart from that my experience with it was that it really was fine. That's not to say you can't get a nice little bump in clarity with a nicer pot but IMO it's an improvement of much less magnitude than adding in the Speedball, for example.

Anyway, great job getting up and running with your Crack and Good luck.  I'll be interested to hear your findings!

[TurbOSquiD77]

Yes, padding the pot with the resistors didn't affect sound quality, it just allowed me more usable range on the dial.  Prior to adding them in, for my preferred volume I was about where you seem to be on the dial (about 8 or 9 O'Clock).  Now around 11 or 12 O'Clock is good - depending on the music and how I'm feeling.

I thought I would just mention it since only replacing the pot might not necessarily solve the issue of high volume that you are having - it didn't for me.

Some people have mentioned a slight channel imbalance at lower volumes with the stock pot, but apart from that my experience with it was that it really was fine. That's not to say you can't get a nice little bump in clarity with a nicer pot but IMO it's an improvement of much less magnitude than adding in the Speedball, for example.

Anyway, great job getting up and running with your Crack and Good luck.  I'll be interested to hear your findings!

Thanks Jeb Jeb. I do experience channel imbalance at low volume levels. I'll research different pots to see what I might be able to afford.

Goldpoint V24 or V47 looks promising. Any other suggestions from what you've experienced/researched?

Also, I'm not quite sure I understand, but does the V24 include resistors installed, and the V24C does not correct? Same with the 47.

[Nathan]

Padding down the potentiometer worked out very well for me with zero downside

[TurbOSquiD77]

Good to know! I may end up doing that while I continue to refine my upgrade plan. It's a little overwhelming seeing hundreds of posts and filtering what info I'd like to keep and what to discard.

Seeing the crazy crack builds with switches and huge caps integrated in really intrigues me. I want to order parts now! haha. But need to find the best and most exact instructions for each mod. If you have any insight/data to share, please do!

[Nathan]

I did many mods to my crack- a few made a nice difference as follows- Teflon bypass caps bypassing the output caps and a choke.  Cardas RCAs made zero difference.

I'm also running nos tubes- tung sol 5998 and a mullard cv4003

[TurbOSquiD77]

I did many mods to my crack- a few made a nice difference as follows- Teflon bypass caps bypassing the output caps and a choke.  Cardas RCAs made zero difference.

I'm also running nos tubes- tung sol 5998 and a mullard cv4003

Nice, I see a lot of people running the tung sol 5998. Ever try a 6as7g/6h13c?

[Paul Birkeland]

Good to know! I may end up doing that while I continue to refine my upgrade plan. It's a little overwhelming seeing hundreds of posts and filtering what info I'd like to keep and what to discard.

The least expensive pot you could use in the Crack will be at least 10x the cost of the resistors you need to pad the stock pot down. 

[TurbOSquiD77]

Cheap affective mods FTW