Donald North Audio — Owners Thread

I've tried a few NOS 5U4GBs and they sound very similar to 5U4G but with less resolution and worse dynamics.

Also, a Sylvania 6BK7B is by far the warmest and thickest input tube. It sounds nothing like any other 6BK7Bs I've owned if you want to go that route. No adapter needed. Also brings the amp's gain down a few DB.

Edit: I meant to add this to my previous comment, not reply to it. Lol.

 

Which 5U4Gs did you find warmest?

 

Honestly for 5U4G I would say NOS Sylvania. I guess I misspoke and was thinking of other variants. Warmest rectifier I tried was the original Sophia Aqua 274B, so I guess not a 5U4G. The new Aqua 274B II is more on the neutral side of things. A bit brighter is the RCA 5U4G, but there are a lot of different ages and levels of use for NOS so they don't all sound the same in my experience. There's a bit of shooting in the dark factor with old tubes.

Brightest 5U4G was a KenRad, but it was also the most resolving tube I've ever owned. But too much treble depending on your chain and other tubes. Has incredible bass impact though. Just amazing extension top and bottom.

Overall I recommend NOS over new production tubes on this amp. All the NP tubes I tried, whether power, rectifier or input didn't have the 'magic' I was looking for. However, I have not heard kilo-buck NP tubes, and I'm only using a Stratus v3 so take my opinion with a grain of salt.

Pretty cheap too. $65 for the Sylvania 5U4G, $10 for the 6N1P EV and $350 to $400 for a pair of good NOS 2A3 tubes, either RCA or Sylvania will do.

Impressions are with Yiggy A2 and ZMF Atrium and JAR 650 mainly.

 

@rhythmdevils , this



Send me your address in PM & I'll send you one, I have several.

 

Yes, but very tastefully so What I've settled on, to make a better contrast with my solid-state amps.

 

@RestoredSparda , I've ordered a couple of the Sylvania 6BK7Bs, will be interested to hear.

I loved the 422A with the Stratus v1, with the Stellaris it hasn't worked out for me so far. I have lots of vintage 5U4Gs and honestly haven't tried them all yet but so far the best match is the new Elrog. Will continue to roll as time permits

 

You may also want to try the Tube Amp Doctor (TAD) 5U4G available through tubedepot.com. Sounds very good in the Supernaut proto.

 

Cool, thanks Donald. I just bought one. They have a code now for about 5 bucks off. Use CYBER10.

Also can't wait to hear a Supernaut some day. What headphones did you mainly tune it with?

 

I can recommend the Hitachi 5Z3 (5Z3 is an equivalent of 5U4G but has a different base, so you’ll need an adapter). It has a balanced, uncolored (a tad warm perhaps), full-bodied sound and is free of treble issues.

 

Ordered a couple. Looks a little Shuguang-y to me

"
Tube Amp Doctor
http://www.tubeampdoctor.com/
Brand(s): TAD
ODM/OEM: JJ, New Sensor, Shuguang, NOS
This German based DIY and instrument amp manufacturer retails a line of tubes from various manufacturer and NOS under their own brand. They have been known to request tubes made to their specification, and to be exclusive retailers of that newly developed tube for a limited duration.
"

 

Any news on this amp?

 

I need to finalize a couple aspects of the design, hopefully by Jan. From there get parts on order.

 

Subbed.

Gonna start a "Mine ships on XXX date" thread to boost my post count, annoy people, and finally get banned.

 

I looked up all of these except the one that needs pins re-routed, and they're often very confusing because the for sale title lists the name that is compatible, but also others that are not compatible and the tube doesn't have the letters for the tube that is compatible written on it.

I'm getting really sick of sellers just throwing in "similar" tubes to the title of FS ads to try to attract buyers and then you think you're getting one thing but wind up with something else that isn't actually compatible. These old Brimar tubes have all kinds of whacky shit written on them. So I just wound up getting a Brimar 13D3. So far, I've found the Brimars compatible with the Stellaris to not sound very "Brimar-y". They've all been too bright and not that wet/warm. The CV 4068, while not that bright is actually the most incisive tube of all the 6BQ7A/6CG7 input tubes.

 

in my experience the 'best' and 'realest' sounding tubes are the earliest made for any given type. I get an amp, put the oldest tubes I can find and afford in it, and if I don't like it, it's not the tubes. For 2A3 that would be the original single-plate 2A3 from 1934. If you put these in an amp you otherwise like, you will get the wet juicy 3D sound.

in my experience with the Stratus, I liked it most with cheap Chinese tubes. When I tried to put the real McCoy in there from the 1930s, the sound became lean and dry. I think that's just how the amp is. I know that's not how the tubes are as I've had those tubes in many other amps. I listened to it with Chinese tubes for a while and sold it. I would chalk it up to the audiophile parts used and the choke-filtered filament supply.

 

Huh. I can't much argue with that. I'm not sure if you mean to compliment the Stratus but that's how I read it: Sounds good with today's available tubes.

 

yup! It doesn't sound bad at all. I was just trying to emphasize that you can have more clarity with older tubes but you'll get more of the amps inherent character which you may or may not like or you can have a more comfortable sound with the inexpensive tubes it ships with at the expense of some clarity.

I think RD wants a sound that is both clear and comfortable and that's a really difficult balance to achieve. for me I only got what I wanted when I started building amps for myself, to have neurotic control over all the variables!

 

And that's where synergy comes in to play, including both source and headphones.

I believe Donald uses the Sonic Frontiers Transport/DAC, which I would assume sounds similar to the SFD1. This is an arguably softer, and less aggressive DAC than Yiggy A2 in my experience.

 

I still use their SFCD1 - love its sound but the laser is starting to occasionally skip again.

I’ve tried vintage Cunningham 2A3 monoplates in my amps and to me they sounded kinda warm, thick and uninvolving. Of course YMMV.