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$100 6922 budget - what durable, low-noise tubes should i consider?


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Hi all - 

 

I've joined the thermionic club with my recent acquisition of a Conrad Johnson ET3SE pre. 

 

As many of you would know, this pre only has a single 6922 and the stock unit is an Electro Harmonix (standard pin).  

 

I'm still burning in the unit as it apparently only had 20hrs on it but ones thing's clear - the valve is toast - there is a lot of tube rush and this is clearly audible at the listening position which is about 4m distant from the speakers. 

 

Soo - i'm on the hunt for a replacement unit.  Vital in this is looking for a durable, low-noise tube given the high gain of the pre (29db) and i'm also after a tight bottom end and smooth mid and tops.  

 

From my research to date and recommendations of a fellow-SNeter it looks like some of the NOS Ruski valves (6N23p-ev - Reflektor) may suit as could the Genalex Golden Lion.  Tesla and Tungsram E88CCs also appear highly regarded. 

 

Interested in opinions on the above or whether I should simply get a new EH?  Budget is max $100 and am open to obtaining from overseas if needed. 

 

Many thanks!

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Thanks everyone for your views.  The 7dj8 option sounds interesting and prices are much more reasonable for NOS.  Are there any CJ owners that have tried this? 
 

 I guess it could be a matter of trying a few 7dj8 and 6dj8 types out.  The Siemens pcc88 looks promising but I may start out with a Genalex gold lion 6dj8/6922.

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Guest deanB
21 minutes ago, Batty said:

the 7dj8 is more durable as the heater is running at 6v instead of 7v when used to replace a 6dj8.

Yes, I picked up that bit of info re 7DJ8 while sifting through the CJ owners website. I think it was claimed that CJ set the heater at 6.3v.

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I would recommend getting a Siemens Munich E88CC early to mid 1960's A-phi valve. Single valves can be found for $100 AUD.

 

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Edited by xlr8or
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10 hours ago, deanB said:

Yes, I picked up that bit of info re 7DJ8 while sifting through the CJ owners website. I think it was claimed that CJ set the heater at 6.3v.

Just confirming that a PCC88/7DJ8 tube was designed for constant current supply circuitry in mind utilising 300mA for heater current.

 

Pre 1959 tube data indicates 7 volt heater supply and post 1959 tube data indicates 7.6 volt heater supply. I thought most CJ tube gear was either AC/DC voltage regulated at the tube heaters - I might be wrong here.

 

Yes - the PCC88/7DJ8 can be used when the 6.3 volt heater supply is exceeded due to higher AC mains supply and when non regulated voltage heater supply is employed in circuit like what is used inside Audible Illusions gear.

Edited by xlr8or
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1 hour ago, xlr8or said:

Just confirming that a PCC88/7DJ8 tube was designed for constant current supply circuitry in mind utilising 300mA for heater current.

 

Pre 1959 tube data indicates 7 volt heater supply and post 1959 tube data indicates 7.6 volt heater supply. I thought most CJ tube gear was either AC/DC voltage regulated at the tube heaters - I might be wrong here.

 

Yes - the PCC88/7DJ8 can be used when the 6.3 volt heater supply is exceeded due to higher AC mains supply and when non regulated voltage heater supply is employed in circuit like what is used inside Audible Illusions gear.

Thanks XLR - so in layman's speak - does that mean a 7DJ8 would be ok?  

 

Re the Siemens unit you mention above is 1973 manufacturing date the key aspect to look for?  It's challenging to search as there are so many that look alike and not all descriptions are comprehensive.  The link provided is for a sold unit.

 

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Guest deanB

@xlr8or, do you have any thoughts about why so many owners of CJ preamps complain about the need to replace the valve every six months to a year?

In the past I've been keen to try one. Have sifted through many forums and the anecdotal evidence around valve longevity from owners past and present is considerable. 

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21 hours ago, Colin Rutter said:

 

I use that tube in a mc stepup.

 

 

Tubes in an MC head amp - I am surprised!  Tubes in a phono stage - yes ... but a head amp?  :o

 

I owned a Trevor Lees head amp decades ago - and couldn't cope with the hiss level.  :(  Then I moved to a ss head amp - which was (and still is) dead silent.

 

Have you ever compared your tube head amp with a ss head amp, Colin?

 

Andy

 

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If you want low noise and durable, you could just get another EH, but get one that's already tested to be balanced, high gain, low noise and microphony. Tubedepot can offer that service and it'll still be a good value purchase ($24 USD total).

https://www.tubedepot.com/products/electro-harmonix-6922-eh-preamp-vacuum-tube

They also have a wide range of other tubes at other price points which you can also get that service on. Note the 15% discount on first purchase if you subscribe to their newsletter.

Edited by Ittaku
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2 hours ago, andyr said:

 

Tubes in an MC head amp - I am surprised!  Tubes in a phono stage - yes ... but a head amp?  :o

 

I owned a Trevor Lees head amp decades ago - and couldn't cope with the hiss level.  :(  Then I moved to a ss head amp - which was (and still is) dead silent.

 

Have you ever compared your tube head amp with a ss head amp, Colin?

 

Andy

 

I now have to be honest.

I haven't finished the mc head amp.

But my mm tube head is acceptably quiet.

Not as quiet as my mc/mm SS headamp.

I doubt a tube head amp could ever be as quiet as SS, but fiddling with things is fun.

My reason for the original reply was based on my experience with Russian tubes.

I have found them to be quieter than many so called hi end tubes.

Edited by Colin Rutter
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13 hours ago, wadiman said:

Thanks XLR - so in layman's speak - does that mean a 7DJ8 would be ok?  

 

Re the Siemens unit you mention above is 1973 manufacturing date the key aspect to look for?  It's challenging to search as there are so many that look alike and not all descriptions are comprehensive.  The link provided is for a sold unit.

 

What a shame - I shared the link in the hope you could pick this up as it was a really good price. However, I suspect a fellow SNAer has picked this up instead - if you're reading this post you need to post your listening impressions of this tube with the toob lovers here when it's received.

 

Back to the question RE A-frame getter support Siemens E88CC tubes. If you're wanting the lowest noise floor then this tube is for you. It was made in the very late 1960's right through to the mid 1970's.

 

More information available here on the different versions:

 

https://www.audioasylum.com/messages/tubes/240117/which-particular-siemens-cca-tube-are-you-making-reference-to

 

PCC88/7DJ8 tubes will work but like ECC88/6DJ8 tubes the earlier ones will exhibit noise. The later A framers from Heerlen and Blackburn are probably best.

Edited by xlr8or
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10 hours ago, deanB said:

@xlr8or, do you have any thoughts about why so many owners of CJ preamps complain about the need to replace the valve every six months to a year?

In the past I've been keen to try one. Have sifted through many forums and the anecdotal evidence around valve longevity from owners past and present is considerable. 

Like the Audible Illusions Modulus range of tube preamps I suspect the voltage is unregulated at the heaters in CJ gear as well. Therefore, PCC88/7DJ8 tubes will be the best option here for the over spec heater supply. This is what is killing the tubes prematurely.

 

You can confirm in-circuit heater supply voltages easily enough with a DVM and a Pomona Electronics 9-pin tube socket adapter with side lugs to measure pin voltages.

Edited by xlr8or
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Philips SQ E88CC gold pins made in Holland. I use this wherever I have to use 6922. I think it's rated 10,000 hours so it's certainly worth the money.

 

https://www.ebay.com.au/itm/PHILIPS-E88CC-6922-SQ-goldpin-single-tube-NOS-tested-on-Avo-163-valves-tubes/283968817671 

 

You can try Siemens or Valvo or Telefunken of E88CC gold pins to suit your system.

 

The best ones are the pinched waist. They are excellent and this is what I like best...but the price is just too astronomical.

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On 06/08/2020 at 7:42 AM, deanB said:

@xlr8or, do you have any thoughts about why so many owners of CJ preamps complain about the need to replace the valve every six months to a year?

In the past I've been keen to try one. Have sifted through many forums and the anecdotal evidence around valve longevity from owners past and present is considerable. 

I did read somewhere that the CJ preamps run the tubes near maximum.

I had a few go noisy after a few months when I had a CJ.

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13 minutes ago, rocky500 said:

I did read somewhere that the CJ preamps run the tubes near maximum.

I had a few go noisy after a few months when I had a CJ.

I've heard this too, and that because of it sometimes CJ valve failures can be spectacular compared to the relatively harmless fizzle most other equipment experiences. But it is just hearsay, I have nothing to back this.

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