Zesto Andros PS-1 Tubes

I'm curious to know if anyone has tried NOS tubes and if so what were your results?

If you actually own the Andros, I believe you must have just purchased it as I remember you considering it in a recent post. If so, why not try to enjoy it with its stock tubes? It's a $4,000 piece of equipment and every single review has been very positive, if not exulting. I don't quite get the urge to change sonic character of components off the bat.

Yes, I have put in 1 set of NOS tubes which are Seimens ecc83 from the 1960's which made for a more airy detailed presentation.I my try a full set of Telefunken's with the diamond emblem on the front at a later date.

I really like the sound of the Zesto Andros. It was ggod with the stock tubes, however, I prefer the sound with the 2 matched Seimens tubes.
Yes, I actually do own the Andros. I simply asked a question for owners that have tried it and what their results were.

Thanks and keep us posted.
Is this the model which uses 12AU7s and 12AX7s? There has been a lot written in general about rolling those 2.
If it's the Phono Stage then certain commonly tried substitutions may not work. The switch I am thinking of in particular is using in 5751s instead of the stock 12AX7s. In a Phono stage, the loss of gain using 5751s may not be desirable. That does not preclude many other common rolls. If you like your sound clean and strong then vintage Telefunkens might sound good. If you want a rich full sound then older Mullards might do the trick, but they are getting truly scarce. The current production Gold Lion 12AX7s have been prized for their rich full sound.
A really special 12AU7 sub are the uber expensive Amperex Heerlen production 7316s. The Stock tubes are pretty good BTW they seem to like the current JJ803S replica, for their 12AX7.
7316s are very good, if you must use a 12AU7 variant. Amperex BugleBoy ECC82s are the best of the true 12AU7s I have heard in my system.
You have a beautiful, brand new component, made with advanced, top quality parts and materials that many would be ecstatic to have. It's like having a new, super hot girlfriend who turns heads on the street, and asking your friends whether she would be better with DD rather than D. I'd myself would enjoy her first just the beautiful way she was before asking for suggestions about improvements, if ever.

Directly on point here, I recently spoke with a successful tube power amp designer and asked him why he decided to go solid state with his phono preamp for a change. He said he was never fully satisfied with the prototypes, and he added that many of his clients who had great sounding tube phono preamps were nonetheless never fully content with the sound and forever continued searching for even better sounding tubes. He offered this was not for him. Perhaps that's something to think about.

06-28-12: Actusreus
You have a beautiful, brand new component, made with advanced, top quality parts and materials that many would be ecstatic to have. It's like having a new, super hot girlfriend who turns heads on the street, and asking your friends whether she would be better with DD rather than D. I'd myself would enjoy her first just the beautiful way she was before asking for suggestions about improvements"

Well at least with tube rolling, it's easy to go back.0:)
The Andros-PS1 comes with four 12AX7 tubes, not 12AU7 as stated by one person above (at least mine did). I have been trying out some Gold Lion tubes for the past few months, and I am liking the results. Fuller sound stage, with deeper bass. The stock JJ tubes sounds great also, but I wanted to see what other tubes sound like in that unit. I am going to try some Tungsol next.
Let us know hwo the Tungsol compare when you try them. Have you asked George what he prefers, if any?
Anybody with new experiences to share on this Zesto 12ax7 question? Anybody
compared NOS Telefunkens with Amperex BBs, Sylvanias, etc.? I see Tonepub
had good results replacing the JJs with EATs - at $225 each, they better sound
I received my Zesto Andros PS1 last Friday. A few days ago I put 4 new production Genalex Gold Lion 12AX7 tubes in the PS1. I think it was a nice improvement. I heard improvements in bass extension, soundstage depth and imaging. I was going to try some NOS tubes but the improvements provided by the Genalex tubes has me very satisfied. So far, I'm greatly impressed by the Zesto.
I've mentioned this to Cfluxa already, but I've compared the stock JJ ECC83s with the JJ ECC803s and heard very little to no difference. I liked the sound of the Gold Lions in my Chinook and wouldn't mind trying those in the Zesto. Smatsui, did you notice more gain with the Lions? I don't need or want any additional.
Tube Rolling on a 4k component from the get go sounds like audionervosa OCD. Why bother buying - build your own kit and tube how you see fit.

That type of feedback will turn alot of potential buyers of the Zesto off - it does me.
Pops, you make no sense.
I didn't notice any additional gain with the Gold Lions versus the stock JJ ECC83s.
You shouldn't hear any additional gain from brand to brand. The eletrical parameters should be the same no matter which brand you choose. The sound however does change in terms of tone, extension and imaging, amongst other things.
Pops are you suggesting we build our own tubes? I doubt you meant that, many of us, including me, don't know how to build a component from scratch. The one thing I can modify quickly, without soldering in most cases, is a tube switch. It affects im the sound in very obvious ways in most instances. It is a rare case that stays unaffected by a tube roll. It is easy and rewarding.
Mechans I wasn't serious about building a tube amp, I was simply saying buying a component for 4k and attempting to change the sound from the designers voicing without giving it some time and getting to know it seems strange to me.
I don't think I have ever rolled tubes in a component without listening to it first. There are some tube which I know I like the sound of and therefore have a low threshold for rolling a tube of that type. For instance I have tube power amps which use 6922s in the input stage. Current production work of course but just don't seem to sound nearly as good as my preferred NOS/OS tube of this type a Mullard CV-2493. In addition, I have made a hobby of collecting tubes of certain types as well, so I like to experiment with them when I get the chance.
I put some UK mullard tubes to replace JJ input tubes and found presentation bigger warmer and more musical.

I did not have additional two for output tubes but will get some more and perhaps some Raytheon and amperex gloves to try.

I have the Orotfon MCA90 cartridge so it's very revealing and fast transients so seems to prefer tubes with fatter midrange
I know have 4 mullard tubes and sounds better still. Might want to try some Amperex or Raytheon. any thoughts?
I lived with the stock tubes for quite a while and was very happy. I only swapped them out when I was chasing some noise gremlins (which turned out to be a preamp tube).

I started with a set of Tungsram-Austria labeled 12AX7's and a set of Telefunken ribbed-plates. Not bad, but seemed to be lacking something....maybe too much of a good thing. I swapped a in set of Mullard M8137's in the front positions since I was familiar with them and put the Teles in the back. This was a good pairing and one that I could live with - balanced without overemphasizing any particular frequency band.

I recently swapped out the front pair of Mullards with some GE 5751 TMBP that were a favorite in the buffer spots of my Minimax. Still plenty of MC gain using a DL103R. Probably a bit more focus.

I'd like to know the tube layout/function for each position. I'm assuming the front spots are the input tubes and the rears are the buffers. One reviewer mentioned swapping only one of the stock JJ's with a Mullard, so........
A co-worker replaced his stock tubes with Psvane Treasure high grade tubes - he is very pleased with htem.
A co-worker replaced his stock tubes with Psvane Treasure high grade tubes (Grant Fidelity)- he is very pleased with them.

Reviving an old thread. Did you ever find out the tube layout for the Andros? I'm using NOS 1960's Brimar's with good performance, but the bass is a little loose and I wanted to try something else. It would be cool if I could try to swap out one pair, but which pair should I start with?
Answering my own question:

Front Left = V1 = Left Output
Rear Left = V2 = Left Input
Rear Right = V3 = Right Input
Front Right = V4 = Right Output

I started tube rolling last night. I have been listening to a set of NOS Brimar's for about a year. They sound great, just a little on the warm side of neutral.

I picked up a pair of 1966 Amperex Holland (labeled Electrohrome) and installed in V1/V4. Brimar's are still in V2/V3. The Amperex appear to have about 2db more gain. The soundstage really opened up, it's much more 3D than the quad of Brimar's. Vocals (both male and female) sounded breathy and fantastic. Everything sounds more lively and I really like this combination.

I have a pair of military Mullard's and a quad of Telefunken's being delivered soon, so I'll try a few more configurations and post my results.
Installed the NOS Military Mullards in V2/V3, Amperex still installed in V1/V4.

At first I couldn't hear a difference between the Mullards and the Brimars. I did notice a slight loss of that Amperex 3D magic. After about 3 hours of play, the Mullards really grabbed control of the bass. This is the first time I've gotten any real slam out of my analog front end!

For reference: VPI Classic 3 -> Sumiko Pearwood Celebration Mk II -> Zesto Andros.

The Telefunkens should arrive in the next couple of days. I'm not sure I'll be swapping the Amperex/Mullard combination out any time soon, but if I try the Tele's I'll post an update.

Just seeing your post now. I recently found my manual and realized that while I had my pairs in the correct spots, I had the input and output positions confused.

I'm still using the Telefunken/Mullard box plate combo but have been thinking of digging out my pair of Amperex short plates. Your description of them pretty much mimics how they sounded in the MiniMax phono. I would imagine similar results in the Zesto Andros.
Rob, thanks for the update. I'm sticking with the Amperex/Mullard config for now.

One update to mention: The 2dB observed increase in gain might have been due to the Brimar's being weak. I installed them as NOS about a year ago but when I pulled them they only tested out at about 50%. Not sure what happened there. I did make the assumption the Andros was self biasing so maybe I damaged the Brimar's? Does anyone know if you need to re-bias the Andros when installing new tubes?
I thought you said it was autobiased. If you change the output tubes on an amp and it is manually biased ,that is when you need to bias the tubes. I never heard of anyone biasing small signal tubes. (I am sure there is an exception out there ...)
So are you happy? It sounds like the tube rolling addiction might have gotten to you. Be careful it is a slippery and steep decent. Best and good luck-
I'm pretty sure that there's no need or way to change the bias on the Andros. I've never had any tube gear that called for biasing of the small signal tubes, like Mechans said.

Sorry to hear your Brimars got tired-out prematurely. I think that my Cary line stage can be hard on tubes (6SN7) but I haven't noticed any of that with the Andros.

I do like what I'm hearing with the M8137 tubes now on the inputs and the Tele ribbed-plates on the outputs.
The Teles are very durable they seem to last forever. Did you get your ECC83 12AX7 = M8137 equivalent NOS NIB. If so it should also have a long life. I am wondering why your Brimar gave out so quickly even if it had a limited lifetime by measurement.
Did you try the New Sensor Gold Lion ECC83? I heard they were sort of Mullard like, sweet and melodious If you don't need all the gain of the 12AX7 you might want to try a 5157. I like them a lot, and now that the NOS and OS (Old Sh*t)12AX7 are getting hard to find.
@Mechans: I bought the M8137s lightly used from a fella who bought them NOS from an online dealer.. I think he had tried them in a Marshall amp and decided he was looking for something else. One NOS tube dealer that I've worked with called the M8137 "the un-Mullard like Mullard tube." The Teles I got from a seller here a while back so I would say they were ANOS, but tested really strong in my B&K 707.

Sorry to hear that Toddc's Brimars didn't hold up for some reason :(