Head-Fi.org › Forums › Equipment Forums › Headphone Amps (full-size) › Little Dot Tube Amps: Vacuum Tube Rolling Guide
New Posts  All Forums:Forum Nav:

Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 117

post #1741 of 7304

The Tesla tubes are from May 1957. Here is a tube chart in English:

 

http://tubes-store.com/article_info.php?articles_id=5
 

post #1742 of 7304
Quote:
Originally Posted by mordy View Post

The Tesla tubes are from May 1957. Here is a tube chart in English:

 

http://tubes-store.com/article_info.php?articles_id=5
 

thank mordy i had that chart already from where i dont remember probably you i know i sent it to those guys when i bought the tesla 6F32v tubes a while back and the guy was happy he posted the chart .also i got a bunch of 6a2p russians for $3.00 each the Tesla just under the critical $8.00 limit Anyways should get them whithin the year lol.last time got something from Russia it took a month guy told me 2 weeks !

!

post #1743 of 7304

Hi Gibosi,

 

Just received two Siemens EH90 tubes in the mail. They are exactly as the ones pictured:

 

http://www.ebay.de/itm/1-Stueck-EH90-Roehre-von-Siemens-nos-neu-/251035838020?ssPageName=ADME:L:OC:GB:3160

 

On the back it says: Foreign. Are these made Phillips?

 

Just plugged them in - sound very good so far. Will reserve judgment until burnt in.
 

post #1744 of 7304
Quote:
Originally Posted by mordy View Post

Just received two Siemens EH90 tubes in the mail. They are exactly as the ones pictured:

 

http://www.ebay.de/itm/1-Stueck-EH90-Roehre-von-Siemens-nos-neu-/251035838020?ssPageName=ADME:L:OC:GB:3160

 

On the back it says: Foreign. Are these made Phillips?

 

Just plugged them in - sound very good so far. Will reserve judgment until burnt in.
 

 

First, look at the glass between the pins. You should see an impressed circle with an alphanumeric character. It is my understanding this marking proves these tubes were manufactured by Siemens.

 

 

 

 

Second, the number printed below EH90 on the glass should also be on the box (271 for mine) like so:

 

 

Assuming these numbers increased with time, it appears that the tubes with ribbed plates are earlier, as the number on my ribbed tube is 201.

 

So I am quite sure your smooth plate Siemens are genuine, and probably manufactured later than tubes with ribbed plates.

post #1745 of 7304
Quote:
Originally Posted by hypnos1 View Post

Acapella 11 : The same plea to you - have you encountered these aspects in your extensive trials? Part of me wants to stay with the strap, the other wants to go - could love/hate relationships also exist in the rolling world? Certainly seems to be creeping into mine!!! Would love to hear your views also - perhaps others might too?...

 

Yes, as pointed out in the former post, where I compared 1/7 and non-strapped non-authentic EK90 (saucer getter, black bottom, no alphanumeric number), there were benefits of both. Ultimately, for focus, 1/7 was better but, dependent on tube, favourite settings may vary. I consider it still work in progress. I guess, we have to hear "us through" and start to converge similarities of our impressions. Detailed descriptions of differences in sound between different straps will help.

 

Attention 1/7-setting here: Since I brought up the 6A2P, I would want to say that in their not perfectly burnt in state, they sound not as precise and clean as the "almost authentic" Siemens production of an EH90 (alphanumeric number: 9, but not replicated on card flap). The Siemens sound that I have experienced so far is relatively open and airy with a good balance and sweet enough treble. The 6A2P sound somewhat less precise, a bit wetter and with a lesser depth of stage, more "forward". As a result, each instrument appears larger in size. The tube sounds generally more forward than other tubes. There is also more wetness to the sound of the 6A2P, their treble is not as present, darker I would say and their bias is more towards the full sounding bass. With all this together, the tube still sounds quite neutral, not exactly tuby. Maybe you get a better impression now. According to my liking, I prefer the Siemens sound I heard, but I can imagine some people liking the more bassy style with a more relaxed treble (1/7-strapped).

 

Having pointed all that out, I must add that all four settings are viable with EF91/92 being most bright, followed by 1/7. Between 2/7 and non-strapped, non-strapped is least forward. To add to the confusion, 1/7 and EF91/92 compete for the most engaging setting. Because of the bassy signature, the added treble is nice and although the bass weight is reduced, bass precision improves. In this setting, the tube "opens up" and sounds cleaner as well, although in 1/7 the bass weight itself is really quite nice. As written above, all settings have in common that the tube does not render a very deep stage.

 

Because of the more forward character and the non ultimate resolution, this tube is probably not my overall favourite (at the moment) but it does sound different to the other heptodes I tested so far, which makes it an interesting buy.

 

So much for now. To be fair, the strapping adds to the level of complexity and I only tried today different 6A2P straps.

 

However none of these tubes reaches the transparency ("clean" sound) and resolution (imaging quality) of the more relaxed, somewhat tubier and not as forward sounding Amperex E91H, which to me (at the moment) sounds best 2/7-strapped. If this tube would be bit more neutral and engaging, that could be it. 

 

Edit 7/7/2013: Forgot a proper recommendation: From my tubes so far, I would suggest the Amperex if you like a more relaxed sound, which becomes lesser relaxed and more engaging using the 2/7-strap, really great. It seems to me that I can indeed hear the special quality of the Amperex E91H. Otherwise the Siemens EH90 (see this post for picture) is an excellent tube.


Edited by Acapella11 - 7/6/13 at 8:03pm
post #1746 of 7304
Quote:
Originally Posted by Acapella11 View Post

 

Yes, as pointed out in the former post, where I compared 1/7 and non-strapped non-authentic EK90 (saucer getter, black bottom, no alphanumeric number), there were benefits of both. Ultimately, for focus, 1/7 was better but, dependent on tube, favourite settings may vary. I consider it still work in progress. I guess, we have to hear "us through" and start to converge similarities of our impressions. Detailed descriptions of differences in sound between different straps will help.

 

Attention 1/7-setting here: Since I brought up the 6A2P, I would want to say that in their not perfectly burnt in state, they sound not as precise and clean as the "almost authentic" Siemens production of an EH90 (alphanumeric number: 9, but not replicated on card flap). The Siemens sound that I have experienced so far is relatively open and airy with a good balance and sweet enough treble. The 6A2P sound somewhat less precise, a bit wetter and with a lesser depth of stage, more "forward". As a result, each instrument appears larger in size. The tube sounds generally more forward than other tubes. There is also more wetness to the sound of the 6A2P, their treble is not as present, darker I would say and their bias is more towards the bass, which is more present and hits hard. With all this together, the tube still sounds quite neutral, not exactly tuby. Maybe you get a better impression now. According to my liking, I prefer the Siemens sound I heard, but I can imagine some people liking the more bassy style with a more relaxed treble (1/7-strapped).

 

Having pointed all that out, I must add that all four settings are viable with EF91/92 being most bright, followed by 1/7. Between 2/7 and non-strapped, non-strapped is least forward. To add to the confusion, 1/7 and EF91/92 compete for the most engaging setting. Because of the bassy signature, the added treble is nice and although the bass weight is reduced, bass precision improves. In this setting, the tube "opens up" and sounds cleaner as well, although in 1/7 the bass weight itself is really quite nice. As written above, all settings have in common that the tube does not render a very deep stage.

 

Because of the more forward character and the non ultimate resolution, this tube is probably not my overall favourite (at the moment) but it does sound different to the other heptodes I tested so far, which makes it an interesting buy.

 

So much for now. To be fair, the strapping adds to the level of complexity and I only tried today different 6A2P straps.

 

However none of these tubes reaches the transparency ("clean" sound) and resolution (imaging quality) of the more relaxed, somewhat tubier and not as forward sounding Amperex E91H, which to me (at the moment) sounds best 2/7-strapped. If this tube would be bit more neutral and engaging, that could be it. 

Thanks for the update Acapella11

post #1747 of 7304

And I thought it might be interesting to show the "sequence number" on the older, ribbed Siemens EH90 tube and box. The number is printed on top of the tube and the box has a paper seal over the top with this number. (I open the box from the bottom.)

 

 

I should say I was quite surprised to see this number on the tube and on the box. There are no numbers on the boxes of my other two Siemens tubes, EK90 and 5654W. That said, judging from the boxes, these EH90 appear to be older, so maybe this practice of putting the "sequence number" on the box was discontinued later.


Edited by gibosi - 7/1/13 at 6:10pm
post #1748 of 7304

FYI

 

I just did a 24 hr burn in on some EK90 tubes and the little dot maintained no problem.

 

Doing another 24 hours on my new RCA 6BY6 tubes since they need it.

post #1749 of 7304

Enquired today at Parts Connexion here in Canada for a socket adaptor to go from ef95 tubes to ef 91- 92 tubes to see if they would make it and how muchfor a pair but for now i use  5-7  wire mod and it works flawlesly will keep you posted.

post #1750 of 7304
Quote:
Originally Posted by MIKELAP View Post

Enquired today at Parts Connexion here in Canada for a socket adaptor to go from ef95 tubes to ef 91- 92 tubes to see if they would make it and how muchfor a pair but for now i use  5-7  wire mod and it works flawlesly will keep you posted.

 

If that's doable I would even consider soldering the jumper on permanently.

 

I really hate those jumpers. angry_face.gif

 

Also does anyone have any info if those 6SN7 adapters would work or not as a 6N6P replacement?


Edited by mab1376 - 7/2/13 at 8:49am
post #1751 of 7304
Quote:
Originally Posted by mab1376 View Post

Also does anyone have any info if those 6SN7 adapters would work or not as a 6N6P replacement?

 

Now, that's a speculative yes. Well, simple thought. They would only design this adapter if under conditions used for 6N6P-operation also the 6SN7 could be used. Heater voltage matches and heater current is lower than for 6N6P-tubes with 0.75 A for 6N6P (0.9 A for 6N6P-I) and 0.3 A for 6SN7.

On a positive side note, you not only add the 6SN7 but also the compatible and appreciated 6SL7 tubes to the list. The gain coefficient is 20 for 6N6P and 6SN7 but 70 (!) for 6SL7.

 

Quote:
Originally Posted by mab1376 View Post

FYI

 

I just did a 24 hr burn in on some EK90 tubes and the little dot maintained no problem.

 

Doing another 24 hours on my new RCA 6BY6 tubes since they need it.

 

That's the spirit! =D


Edited by Acapella11 - 7/2/13 at 11:57am
post #1752 of 7304
Quote:
Originally Posted by Acapella11 View Post

 

Now, that's a speculative yes. Well, simple thought. They would only design this adapter if under conditions used for 6N6P-operation also the 6SN7 could be used. Heater voltage matches and heater current is lower than for 6N6P-tubes with 0.75 A for 6N6P (0.9 A for 6N6P-I) and 0.3 A for 6SN7.

On a positive side note, you not only add the 6SN7 but also the compatible and appreciated 6SL7 tubes to the list. The gain coefficient is 20 for 6N6P and 6SN7 but 70 (!) for 6SL7.

 

 

That's the spirit! =D

 

Maybe in a few weeks i'll buy those adapters and a new stock set of the 6sn7 and 6sl7 to try.

 

I plan on eventually buying the VI+ anyway which can use those tubes.

post #1753 of 7304
Quote:
Originally Posted by Acapella11 View Post

 

Yes, as pointed out in the former post, where I compared 1/7 and non-strapped non-authentic EK90 (saucer getter, black bottom, no alphanumeric number), there were benefits of both. Ultimately, for focus, 1/7 was better but, dependent on tube, favourite settings may vary. I consider it still work in progress. I guess, we have to hear "us through" and start to converge similarities of our impressions. Detailed descriptions of differences in sound between different straps will help.

 

Attention 1/7-setting here: Since I brought up the 6A2P, I would want to say that in their not perfectly burnt in state, they sound not as precise and clean as the "almost authentic" Siemens production of an EH90 (alphanumeric number: 9, but not replicated on card flap). The Siemens sound that I have experienced so far is relatively open and airy with a good balance and sweet enough treble. The 6A2P sound somewhat less precise, a bit wetter and with a lesser depth of stage, more "forward". As a result, each instrument appears larger in size. The tube sounds generally more forward than other tubes. There is also more wetness to the sound of the 6A2P, their treble is not as present, darker I would say and their bias is more towards the full sounding bass. With all this together, the tube still sounds quite neutral, not exactly tuby. Maybe you get a better impression now. According to my liking, I prefer the Siemens sound I heard, but I can imagine some people liking the more bassy style with a more relaxed treble (1/7-strapped).

 

Having pointed all that out, I must add that all four settings are viable with EF91/92 being most bright, followed by 1/7. Between 2/7 and non-strapped, non-strapped is least forward. To add to the confusion, 1/7 and EF91/92 compete for the most engaging setting. Because of the bassy signature, the added treble is nice and although the bass weight is reduced, bass precision improves. In this setting, the tube "opens up" and sounds cleaner as well, although in 1/7 the bass weight itself is really quite nice. As written above, all settings have in common that the tube does not render a very deep stage.

 

Because of the more forward character and the non ultimate resolution, this tube is probably not my overall favourite (at the moment) but it does sound different to the other heptodes I tested so far, which makes it an interesting buy.

 

So much for now. To be fair, the strapping adds to the level of complexity and I only tried today different 6A2P straps.

 

However none of these tubes reaches the transparency ("clean" sound) and resolution (imaging quality) of the more relaxed, somewhat tubier and not as forward sounding Amperex E91H, which to me (at the moment) sounds best 2/7-strapped. If this tube would be bit more neutral and engaging, that could be it. 

 

Edit: Forgot a proper recommendation. From my tubes so far, I would suggest the Amperex if you like a more relaxed sound, really great. Otherwise the Siemens EH90 (see this post for picture) is great, my favourite at the moment.

 

Hi A11,

 

Thanks for your reply. Once again I am in awe of your ability to dissect what is entering your ears, and then describe same in such depth...are/were you in sound engineering perchance?

 

Whatever, I feel totally inadequate! I wish I could describe in your terms what I mentioned as 'apparent loss of overall control in complex instrument (electronic) and vocal pieces', eg some Genesis/Duke tracks. Am I wide of the mark in associating this with your term 'focus?' Is what I am trying to convey rather the opposite - UNfocussed? Perhaps you can put this poor sinner on the right track to enlightenment...

 

So much to learn, so little time...

 

Cheers.

post #1754 of 7304

Always learning something new. If you already know this, just skip it.beyersmile.png

 

Many times when you buy something it states make best offer. In the past I would suggest something reasonable. If an item is $5 I would suggest $4 (works better with Euros cause a Euro is around $1.30, lol), and usually the seller would agree.

 

Today I submitted a ridiculous offer for less than half of the price which usually results in a flat out refusal. Instead of rejecting the offer, the seller made a counter offer for 33% off, which I accepted. (The counter offer is my new experience.)

 

So here is my thought: If the seller has a best offer feature, make a low offer and add in the message box that you are open for a counter offer. Might work better than submitting a second offer.

post #1755 of 7304
Quote:
Originally Posted by mordy View Post

Always learning something new. If you already know this, just skip it.beyersmile.png

 

Many times when you buy something it states make best offer. In the past I would suggest something reasonable. If an item is $5 I would suggest $4 (works better with Euros cause a Euro is around $1.30, lol), and usually the seller would agree.

 

Today I submitted a ridiculous offer for less than half of the price which usually results in a flat out refusal. Instead of rejecting the offer, the seller made a counter offer for 33% off, which I accepted. (The counter offer is my new experience.)

 

So here is my thought: If the seller has a best offer feature, make a low offer and add in the message box that you are open for a counter offer. Might work better than submitting a second offer.

 

Recently, I made a ridiculously low offer for a pair of tubes. (Primarily because the vendor was charging almost $11 to ship two tubes from Virginia to Ohio!) He rejected my offer and then blocked all communication from me, including submitting any future offers! Please forgive my language, but what a jerk! ahaha... :)

New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Headphone Amps (full-size)
Head-Fi.org › Forums › Equipment Forums › Headphone Amps (full-size) › Little Dot Tube Amps: Vacuum Tube Rolling Guide