EAR 834P tube rolling

Mccsiz · **Posted:** Sun Nov 01, 2009 12:34 pm

Will do ph

I especially want to know his opinion on using 12BH7 tubes.

Cheers,
Loyd

rabinowicz · **Posted:** Sun Nov 01, 2009 2:24 pm

A few things:

I wrote to Tim deP shortly after I got my 834P asking about the use of an AU7 in V3. He dismissively poo-pooed it. I haven't heard consistent suggestions for an AU7 in V1, the gain stage. Here there are lots of suggestions for a 5751 which I tried and didn't like.

Despite T's warning I did use an AU7 in V3 for quite a while. Then I replaced it with an AX7 and was shocked at the improvement the AX7 made. Not surprisingly, Tim was right. Overall my eight years of experience with this phono stage is don't muck about. Stay with three AX7s.

I've tried a number of current production AX7s. Your EIs were the best. Those are the ones I'm using. There are better NOS AX7s around but not that many. If you find one, put in in V2. That's where you'll get the best advantage.

I just replaced the stock power cord with a home-made $30 "asylum" cord (google it). Big improvement.

phowell1 · **Posted:** Sun Nov 01, 2009 2:46 pm

Rabinowicz- Have you tried the TJ 'full music' tubes in there, or has anybody? I have heard nothing buy raves about thes. I f anyone has tried this, please do leave your impressions!

THat article in goodsoound looks interesting. Maybe I should try building an all out 834. Then, maybe I should learn to solder first....Has anyone tried those mods?

rabinowicz · **Posted:** Sun Nov 01, 2009 4:15 pm

[quote="phowell1"]Rabinowicz- Have you tried the TJ 'full music' tubes in there

No.

Pneumonic · **Posted:** Mon Nov 02, 2009 1:32 pm

Mccsiz wrote:

I have been checking into tubes the last while. I bought an NOS 12AU7 Blackburn Mullard to try out in the step-up stage of the EAR. It won't arrive for about two weeks. I have also been checking into the 12BH7's. I found this one Kerry. Is it what you meant by "try a 12BH7 in place of the 12AU7. Warmest of these to my ears are the grey, 60's RCA round getters":

For Sale "1960's RCA 12BH7-A tubes-G. P, O"? I would appreciate some direction before purchasing the tube.

Loyd, they would appear to be them, yes. You may also wish to consider the Ei Elite 12BH7's also. FYI, the Tung Sol and Sylvania 12BH7's are more on the bright and detailed side of things so you will wish to avoid them. The GE's in-between. If you were close by I'd lend you one or two of mine to try out. Anyone in BC have a spare RCA's around?

Most everytime I have subbed a BH7 in for a AU7 the results were for the better. Note however that the 12BH7's draw about twice the heater current of a 12AU7 so the cct design needs to be willing and able to run them properly. If Tim DeP is accessible he'd obviously be able to tell you one way or the other.

Also the gain going from AX7's to AU7's is significant (on opposite sides of the gain spectrum) so the sound will be different. Depending on cct design, I suppose you could alsoconsider the in-between tubes in the family as well - AT7, AY7 and AV7. Again, Tim DeP is the guy to ask about this.

Good luck

- Kerry

phowell1 · **Posted:** Mon Nov 02, 2009 3:38 pm

I read that the heaters on the 834 are run in series and so one needs to be conscious of heater current draw from any tube one is going to use.

Uunderhill · **Posted:** Mon Nov 02, 2009 4:24 pm

Yaukui wrote:

Loyd,
Why don't you contact Tim de Paravicini and ask him about it. He designed it and knows more about it than anybody...
... he has always been helpful, insightful, and gracious, even though it's not one of his current products. His email is earyoshino@aol.com

The voltage gain of a phono stage is about 250 times.

Could ask Tim de Paravicini if he thinks putting shields on the tubes will help reduce noise.

Also, you may want to read up on Joe S tube Lore, for opinions on 12AX7's and 5751's.
http://www.audioasylum.com/scripts/d.pl ... html#12AX7

Pneumonic · **Posted:** Mon Nov 02, 2009 5:30 pm

phowell1 wrote:

I read that the heaters on the 834 are run in series and so one needs to be conscious of heater current draw from any tube one is going to use.

If so then I certainly would be cautious about going the BH7 route until confirmation is found.

Mccsiz · **Posted:** Mon Nov 02, 2009 11:14 pm

Thanks guys:
I'm already doing some of the research. I'll let you know my findings.
Cheers,
Loyd

Mccsiz · **Posted:** Tue Nov 03, 2009 7:57 am

Here is something new (what do you think, Kerry):

TechTubes from the updated, old Mullard Blackburn England factory
[url][/url]https://shop.blackburnmicrotech.com/stock_list.php?categoryid=1[url][/url]

Cheers,
Loyd

Mccsiz · **Posted:** Tue Nov 03, 2009 8:24 pm

Uunderhill wrote:

Yaukui wrote:

Loyd,
Why don't you contact Tim de Paravicini and ask him about it. He designed it and knows more about it than anybody...
... he has always been helpful, insightful, and gracious, even though it's not one of his current products. His email is earyoshino@aol.com

The voltage gain of a phono stage is about 250 times.

Could ask Tim de Paravicini if he thinks putting shields on the tubes will help reduce noise.

Also, you may want to read up on Joe S tube Lore, for opinions on 12AX7's and 5751's.
http://www.audioasylum.com/scripts/d.pl ... html#12AX7

Paul,
As usual, you are a beacon

Cheers,
Loyd

Pneumonic · **Posted:** Tue Nov 03, 2009 8:36 pm

Mccsiz wrote:

Here is something new (what do you think, Kerry):

TechTubes from the updated, old Mullard Blackburn England factory
[url][/url]https://shop.blackburnmicrotech.com/stock_list.php?categoryid=1[url][/url]

Cheers,
Loyd

Sorry, Loyd. No personal experience listening to those reissues.

They sure look the part ..... though the description that says "with improvements in speed and clarity the TechTube™ valve delivers detail you never knew existed" I'm not so sure it'll be warm sounding as you prefer.

- Kerry

Pneumonic · **Posted:** Tue Nov 03, 2009 8:40 pm

BTW, Loyd.

Other AU7 substitutes for low current apps are 5814, 6189, and 5963.

Mccsiz · **Posted:** Wed Nov 04, 2009 1:06 am

The Amperex 12AU7 just snapped into place.
This is audio bliss :shock:

The EAR is incredible :!:

OK! OK! I'll get back to you all when I'm back on the ground. In an effort to make a grounded thought... I must admit that I am surprised by this component. I really didn't expect it to sound so much better than the Musical Fidelity phono stage in my 308 pre amp. How amazed am I? Look at what time :shock:

; it is (midnight in BC) :!:

And I'll be getting up for work in five and a half hours.

Cheers,
Loyd

Pneumonic · **Posted:** Wed Nov 04, 2009 9:51 am

Mccsiz wrote:

The Amperex 12AU7 just snapped into place.
This is audio bliss :shock:

The EAR is incredible :!:

OK! OK! I'll get back to you all when I'm back on the ground. In an effort to make a grounded thought... I must admit that I am surprised by this component. I really didn't expect it to sound so much better than the Musical Fidelity phono stage in my 308 pre amp. How amazed am I? Look at what time :shock:

; it is (midnight in BC) :!:

And I'll be getting up for work in five and a half hours.

Cheers,
Loyd

Thumbs up when this happens, Loyd. Not the lack of sleep part but, rather, the enjoyment factor when something new introduced into the system works out with flying colours.

Canuck Audio Mart

EAR 834P tube rolling

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