[Official] Big Brain Stack - Owner's Thread

Damn. I didn’t think about the changes that I made to my recommendation post getting blown away doing the site fix. I’ll work on that sometime in the next day or two.

EDIT: The Recommendation Post has been updated.

1 Like

You need to get this for your SYS:

Now I have a use for the other knob from the 2 pack I bought for the Atom. Nice.

Either will work on the SYS. I bought that one first and it doesn’t fit the atom, hole is recessed too far.

1 Like

Ok we’re in business

3 Likes

Are the tube upgrade instructions somewhere else? I saw on the youtube comments to look here for more info.

I just ordered all the parts for the BBS, but I haven’t ordered the tube upgrades yet. Also, I was hoping to find a single vendor for both tubes, as opposed to ebay and tube-store.com. Anyone know what I need to be looking for specifically when purchasing upgrade tubes? It’s all well past my understanding at this point.

@ALANMAN is the tube guru, I’m sure he will be able to point you in the right direction.

1 Like

The reason why the 2 tubes listed were chosen is price and availability. Other tube equivalents can be found but not cheaply or easily.

The P20 accepts 4 equivalent tubes: 6N3, 5670, 2C51, and 396A.
Only 1 variant each of 2 different types are relatively cheap and readily available, the Reflektor 6N3P-DR and the GE 5670W.

The GE 5670W are the cheapest 5670 variant and also very good. There may be other brand variants worth trying for the 5670. I’m very interested in hearing the Raytheon 5670, as they seem to be the second cheapest and moderately available on ebay, averaging about 20-35 USD per tube. Other 5670 variants are very expensive, up to 100 USD or more per pair.

I have tried all of the 6N3P tubes available at tube-store. A few are OK at best, and a couple are not worth trying. The Reflektor brand DR are the best, and actually great. Everything about the DR variant goes well beyond any others listed on the site. It is also the most expensive, but at $6 per tube it’s an easy buy.


By far the most expensive of these equivalents is the Western Electric 396A. This tube is prohibitively expensive for me to try. The Western Electric 396A is said to be the warmest and most ‘tube’ like of all it’s equivalents, some consider it to be the best. This is well known and drives the price up. Used and dying 396A tubes still go for 60-100 USD per tube. New can go anywhere from 200-500 USD PER TUBE.

I am unfamiliar with specific 2C51 variants, but like each other equivalent, you’ll see the 2C51 name grouped in with the other types when doing a search.

2 Likes

One thing to note on the 5670W, they are quite a bit shorter than any 6n3 / 6n3p variants. If you have trouble removing them from your P20, just gently and patiently wiggle them back and forth until they come loose, it may take a few minutes. The seller also likes to use alternative ‘packing material’






1 Like

Got a tube upgrade delivered today! I’m utterly devastated that my applesauce packing peanuts are over a year expired. I was really looking forward to trying out the strawberry apple flavor.

I think that I’ve made an error in purchasing. I only bought one of each tube, thinking that they were to be used together as a Frankenstein pair. But you were meaning to buy two of each of the recommended tubes correct? Would putting one of each of the above recommended tubes in at the same time on the p20 be a bad idea, or not a big deal at all?

The tubes are meant to be used as a pair and need to match. There is one for each channel, Left and Right. Please DO NOT mix and match tube types, this will sound bad and can damage the amp.

1 Like

Awesome. Thanks for clarifying. Not sure why I didn’t assume that originally.

1 Like

I hate to do this to ya’ll, but you guys need a DarkVoice 336SE.
It was last on Drop/Massdrop for $200 shipped.

It sounds fantastic and has a ton of power, even on single ended. It would be a great option for those of you doing a higher end BBS, with a balanced THX AAA 789 and the DV single ended.

1 Like

The evolution and current iteration of my Big Brain Stack

2 Likes

sigh

Where’s the DarkVoice?

1 Like

I’d like to think I played a small part in this acquisition.
But now the FOMO is kicking in dammit.

I should be getting my RCA driver tubes in later this week, I’ve already put in a RCA power tube.
It’s sounds great as-is with the stock tube, but I hear it really opens up even with a $10 tube swap.

2 Likes

Not super related to this, but JDS ATOM DAC available today.

2 Likes

DarkVoice is available for $200 at DROP.

2 Likes