[TomSix]

Has anyone tried to use the GZ37 CV378 Philips/Mullard as replacement for the current GZ34 / 5AR4? Are the G37 and GZ 34 compatible? I am looking at one NOS Mullard GZ37 from the 1960 as replacement of my current stock JJ. I am currently running two Marconi 6V6 and a GE-Ken Rad 6SN7GT Black Plates 1949, the latest has brought back balance tot he SS after the Marconi introduced a little narrow soundstage but amazing smooth, "tuby" sound. Any feedback from the forum and its amazing and knowledgeable members is highly appreciated.

MelaVerde,

I would hesitate to recommend using a GZ37 type rectifier in place of the specified GZ34 type rectifier used in the Studio-Six.

Yes, both tubes have identical base/pin connections, so that's not a problem. The GZ37 requires 2.8 amps of filament current, and that's no problem either, because the ST-6 power transformer is rated at 3 amps max 5V filament voltage.

A caveat, however, is that the GZ37 specifications are for a maximum of 4uF capacitance in a capacitive input filtering connection, and the ST-6 has 24uF input filter capacitance, and so exceeds the specified limit for the GZ37. This may or may not cause a failure of the tube in actual practice, but I would caution against taking the chance.

Also: the GZ37 has over three times the voltage drop of a GZ34/5AR4 type rectifier, and so you would get a reduced B+ voltage to the Studio-Six as a result. This could particularly be an issue if/when using the Studio-Six phono stage.

A likely result with the GZ37 would be a softer, less dynamic sound with decreased bass performance as compared to the specified GZ34/5AR4.

So yes, I do suggest staying within the GZ34/5AR4 family of rectifier tubes for the Studio-Six.

I believe you will likely find that trying various varieties of 6V6 type output tubes is the most effective route towards finding a sonic presentation from the ST-6 which most suits your personal tastes.

I hope that helps

 

[MelaVerde]

MelaVerde,

I would hesitate to recommend using a GZ37 type rectifier in place of the specified GZ34 type rectifier used in the Studio-Six.

Yes, both tubes have identical base/pin connections, so that's not a problem. The GZ37 requires 2.8 amps of filament current, and that's no problem either, because the ST-6 power transformer is rated at 3 amps max 5V filament voltage.

A caveat, however, is that the GZ37 specifications are for a maximum of 4uF capacitance in a capacitive input filtering connection, and the ST-6 has 24uF input filter capacitance, and so exceeds the specified limit for the GZ37. This may or may not cause a failure of the tube in actual practice, but I would caution against taking the chance.

Also: the GZ37 has over three times the voltage drop of a GZ34/5AR4 type rectifier, and so you would get a reduced B+ voltage to the Studio-Six as a result. This could particularly be an issue if/when using the Studio-Six phono stage.

A likely result with the GZ37 would be a softer, less dynamic sound with decreased bass performance as compared to the specified GZ34/5AR4.

So yes, I do suggest staying within the GZ34/5AR4 family of rectifier tubes for the Studio-Six.

I believe you will likely find that trying various varieties of 6V6 type output tubes is the most effective route towards finding a sonic presentation from the ST-6 which most suits your personal tastes.

I hope that helps

Tom,

as usual, thank you for your quick reply, technical explanation, it makes very much sense as I am learning more and more of tube technologies. The current rectifier is good and the combination of the Marconi 6V6 and the Ken-Rad 6SN7GT Black plate seems to have brought the desired results. I will stick to your suggestion and focus on the rolling of these two sets of tubes, but as it stands I am very happy with what I am hearing out of the SS. I hope I did not take too much valuable time out of your California relocation.

Best regards,

Fabio C

 

[TomSix]

MelaVerde,

Absolutely no problem. I don't check into this thread daily, but I do try to stop by at least once or twice a week, and see what's going on.

Your questions are relevant to any user/owner of the Studio-Six, and so such discussion in this forum is potentially of assistance to others as well.

It's my pleasure.

 

[fhuang]

Chiang,

after few hours on it I start to like them very much. Initially I thought that the SS with the standard tubes sounded good but a little sterile or lifeless if you will, as I invested in a tube amp, coming from the Hugo TT which I now use strictly as DAC, I was expecting a more warm and liquid sound rather than the more precise and analytical that I was getting. Some of the sibilance of my Fostex TH900MK2 is gone, my beloved Sade sound more natural and inviting, the bottom end of the Mark Knopfler guitar in Brothers in Arms has a more lower register and control. The downside, in my modest opinion, is the soundstage or the reduction of, it seems to me to be smaller narrower if you will, in some instances I miss some of the openers of the previous setup but in the other hand it does make some of my small jazz assembles sounds like they are performing in an empty and reverberating auditorium instead of a smoky small club.

The attack and release on the drums seems slower too, while before it felt quick and sharp with a great sense of size on the instrument now it feels a little slower and constrained. You will have to forgive me if I failed to convey my impressions but I am neither a good writer and English is not my first language, I hope what I said make in somehow sense. I am sorry they did not work out for you but I believe these tube deserve a place in the SS if properly paired with a more revealing 6SN7, I am thinking to try a Northern Electric in this regard or something else but here your greater experience and knowledge can fill the gap I left in my sentence.

Best regards,

different source and different headphones with different tubes. the marconi supposed to be very musical. any new changes lately on the tubes?

 

[fhuang]

Has anyone tried to use the GZ37 CV378 Philips/Mullard as replacement for the current GZ34 / 5AR4? Are the G37 and GZ 34 compatible? I am looking at one NOS Mullard GZ37 from the 1960 as replacement of my current stock JJ. I am currently running two Marconi 6V6 and a GE-Ken Rad 6SN7GT Black Plates 1949, the latest has brought back balance tot he SS after the Marconi introduced a little narrow soundstage but amazing smooth, "tuby" sound. Any feedback from the forum and its amazing and knowledgeable members is highly appreciated.

i have some gz37 and it's my favorite with another amp(wa5). still i wouldn't try them with the studio six because of a)what tom said and b)it would really sound too soft. gz37 to me, the positive, very mucial and tubey. the no so positive(i hate to use the word negative) soft and lack dynamic.

 

[MelaVerde]

i have some gz37 and it's my favorite with another amp(wa5). still i wouldn't try them with the studio six because of a)what tom said and b)it would really sound too soft. gz37 to me, the positive, very mucial and tubey. the no so positive(i hate to use the word negative) soft and lack dynamic.

Thank you fhuang for the feedback I will keep in mind the suggestion from you and Tom and stick with a GZ34

 

[MelaVerde]

different source and different headphones with different tubes. the marconi supposed to be very musical. any new changes lately on the tubes?

Tubes have changed a bit but still retained their musicality, the addition of the GE-Ken Rad 6SN7GT black plates has made the entire dynamic between the tubes much more exciting, very happy at the moment!!!! Currently I am using an Audeze LCD-3 still have 3 weeks before I can send it back for full refund, although not what I was expected it is rapidly growing on me.

 

[TomSix]

Anyone make it down to LA last weekend for the big CanJam?

 

[Currawong]

Did you see the CanJam Impressions thread?

 

[TomSix]

Did you see the CanJam Impressions thread?

I did.

This year's SoCal CanJam impressions thread seems a little thinner and short of photos compared to previous years, *if* memory serves me.

I just rechecked it, and do note a little more content has been posted in the last 24 hours.

Regrettably, I simply couldn't make it this year as originally hoped. I'm prepping for an upcoming 600 mile household move, and so my schedule was incompatible.

Was just wondering, in particular, if any Studio-Six people made the show.

 

[longbowbbs]

I missed it for the firt time in several years. My sons had his 21st birthday that weekend.

 

[TomSix]

I missed it for the firt time in several years. My sons had his 21st birthday that weekend.

Family should always come first --I fully understand.

I was looking forward to making it down and catching up with a few people, and also making connections with some folks I have yet to meet.

The SoCal CanJam has become a significant annual industry event.

I'm determined to make it next year; indeed I'm intent to move down to live in the LA area. The warmer/drier/sunnier SoCal climate agrees with me. The arts and cultural resources I find quite attractive too. And needless to say, SoCal is certainly a major locus of Hi-End audio.

 

[meomap]

Hi @TomSix,

I am trying to buy a 6SN7 tube from Sophia Electric.
They said their 6SN7 is equivalent to 6SN7GTA, not GTB.

Current tube in mine is is ALO stock of GE 6SN7GTB. They said GTB is high voltage.

What is the difference between B and A?

Can I use their 6SN7 tube into this 6SN7 slot?

Thank you in advance.

 

[TomSix]

Hi @TomSix,

I am trying to buy a 6SN7 tube from Sophia Electric.
They said their 6SN7 is equivalent to 6SN7GTA, not GTB.

Current tube in mine is is ALO stock of GE 6SN7GTB. They said GTB is high voltage.

What is the difference between B and A?

Can I use their 6SN7 tube into this 6SN7 slot?

Thank you in advance.

Meomap,

I fully understand the logic of your question and concerns.

The good news: essentially any 6SN7 family tube, ST, GT, GTA, GTB etc., can be used in the Studio-Six without incompatibility issues.

In the Studio-Six, the 6SN7 is very under-stressed in terms of voltage and current, and so there is no problem with such parameters.

Do let me know if I can further help.

Good luck with your tube-rolling efforts!

-Thomas

 

[meomap]

Meomap,

I fully understand the logic of your question and concerns.

The good news: essentially any 6SN7 family tube, ST, GT, GTA, GTB etc., can be used in the Studio-Six without incompatibility issues.

In the Studio-Six, the 6SN7 is very under-stressed in terms of voltage and current, and so there is no problem with such parameters.

Do let me know if I can further help.

Good luck with your tube-rolling efforts!

-Thomas

Thank you so much. I will let them know tomorrow .