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Doge 8 Clarity: 12AT7 replacement for phono stage

Hello fellow enthusiasts... My apologies in advance for the noob question.

I've put together my first all tube system, as far as preamp and amp combo is concerned. Looking to see IF replacing the phono section's 12AX7 (Mullard ECC81) tubes with lower gain 12AT7 in my Doge 8 Clarity 2017 ed. will help lower the "hiss"/ tube rush coming off with my current set up. Doge's phono setting is on MM (using Bob's Device Sky 20 SUT), Phono: 47k, tried both normal and low sensitivity, (- 8) gain reduction, but "hiss" is still audible from my seat 7' away from the speakers. 

I'm looking at replacement tubes from Upscale - Mullard 6201 which they claim to be the "quiet" ones. Not sure if it will help in lowering the hiss I've described.

Doge's line level still holds the stock 12AT7 tubes and to me - they sound nice as the reviews online says. I'm sure it can do better with tube rolling. No audible hiss from my seat. Switching between any line level onto phono input clearly augments the hiss.

To take advantage of Doge's much improved line level over the phono, I've utilized my only external phono stage - Schiit Mani. Not ideal but i can handle that better than deal with the hiss using the Doge's internal phono stage. I've contemplated on just upgrading to a nicer phono stage but that's another topic.

So, will it work to replace the 12AX7 with lower gain tubes 12AT7 to decrease hiss in my system? 

Thank you in advice for your time and responses.

Current system:
Rega P3 (2016), NEO ttpsu, DV 20X2L
Schiit Mani to line level vs Bob's Device Sky 20 to phono level
Doge 8 Clarity 2017 ed.
Mystere PA11 
KEF R3 on stands



oyie2000

Showing 6 responses by oyie2000

oyie2000 OP
13 posts
 
Good morning... thank you for the responses. What can I say? You guys are amazing here by providing info and direction...

@ tomcy6: Thank you for the link. 

@ lowrider57: As I mentioned, I'm fairly new to tubes and have not come across info on the low noise 5751s, and will definitely read more into it. Thank you for the direction. Doge is known for their excellent line level, but not much to revel about its phono stage. Nonetheless, I was being optimistic of having less ICs by using the Doge's internal phono stage. Not losing hope yet. I'll reach out to Vintage Tube and see what they say. 

@ grey9hound: Talking about making it easy... thank you for the contact info. 
oyie2000 OP
13 posts
 
Since I'm happy with the Doge 8's line level, it seems easier to just upgrade from Mani to a higher quality phono stage.... but I'm not quite ready to give up on the Doge's phono and where's the fun in that, right?

But hey, feel free to make recommendations for phono stage appropriate for my current system as described:

Rega P3 (2016), NEO ttpsu, DV 20X2L
Schiit Mani to line level vs Bob's Device Sky 20 to phono level
Doge 8 Clarity 2017 ed.
Mystere PA11
KEF R3 on stands

When i said "appropriate" to my setup, i meant each piece of my system cost me about +/- $1,000 (minus Mani), I guess I wouldn't want to spend 2 or 3 times the amount of my cart, etc. Not sure if that is a "sound" approach - no pun intended. 

Again, thank you in advance.
oyie2000 OP
13 posts
 
@ kalali: Thank you for the correction. I'm the second owner of this Doge and the previous owner rolled the stock tubes. After checking the tube boxes, its the reissued Mullard 12AX7. With Mani running into one of the line levels - No issue with hiss I described compared to running straight to the phono section.

@ bsmg: I've tried different phono sensitivity setting and applying Doge's  (-8) gain reduction - still find the hiss an issue for me. I would definitely check out those tube recommendations (5751 & 7025). 

@ atmosphere: Being the second owner of the unit, I'm not sure if I'm able to avail any warranty on the unit. Without any other matching tubes around, I may have to pony up with replacement tubes to see if the phono section's hiss issue I'm having can be remediated.

@ chayro: Nice to learn more about different tubes. Glad to hear you had good experience with Black Sable and its characteristics. It appears everyone here are in consensus about the guys at Vintage Tube Services.

Thank you all for chiming in. Much appreciated!
oyie2000 OP
13 posts
 
@ atmasphere: I appreciate your input and guidance. I know you're well respected in these forums. I will do the test you recommended I do, and will report back.

@ mulveling:  Thank you for the valuable tips in increasing signal to noise. Looks like I will have to really look at a good set of quality, quiet, MC phono grade tubes compatible with my Doge 8 to properly achieve my goal. 

@ robertplata: Splurging! Yes, and as mentioned above, I will have to pony up for the "right" tubes. 

I'm glad I posted this question of mine, as I was ready to pull the trigger on some tubes that I would have not been able to return. That would've been an expensive experiment. 

oyie2000 OP
13 posts
 
I have to say, you all have been great in sharing your wisdom about this awesome hobby and passion we all share. I thought I've read enough about tubes but I obviously have yet to scratch the surface per se. The last 24 hours have been very informative. Thank you all!

@ bdp24: RAM Tube Works - definitely worth checking out. If it wasn't for work getting in the way ; ) - I would've made some headway in calling about the tube recommendations here.

@ lowrider57: the brief moment i got to check iPhono2 online - it appears to be a good contender for what i'm looking for. I'll have to do some more research, and see some comparison reading between that and the DV P75 which both are under $1k and falls under my budget in case I go that route.

@ jsautter: I was actually thinking of using 12AT7 instead of 12AX7 on the Doge's phono stage which requires the latter. I will contact Doge Audio to check whether it is even feasible what I'm trying to do, or better yet, see what they have to say.

oyie2000 OP
13 posts
 

OP here and it's been a while, but I'd like to share an update. Ended up with PSVane 12AX7LS black tubes from Grant Fidelity before they quit selling PSVane tubes. Picked the highest grade tubes available, burned-in through the line stage for almost 200 hours (as advised by Brian of Doge). Hiss still present and not much different than what with Mullard tubes it replaced. 

I jumped on a nice deal for a SS phono stage DV P75 mk4 going through the excellent line stage of the Doge 8, and that was a nice combo without the hiss of the phono stage in the Doge 8.  I've since moved on to a Sutherland 20/20 w/ LPS and that's even a better combo. DV XX2 mk2 cart & Bob's Sky 20 in line. 

In retrospect, I should've just jumped on a quality SS phono stage from the get go since rest of my system consisted of tube pre and power amps. Doge 8's line stage is well-regarded and I should've known that pairing with SS phono thru Doge 8's line stage would work like a charm.

But hey, where's the fun in landing the right combo from the get go?!?

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