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 113

post #1681 of 7300
20130626_173736_zps08695c1b.jpg

These just arrived. Letting them burn in but i noticed a drastic difference in low end punch and overall clarity over the stock GE tubes with both my 325i and WS99.
post #1682 of 7300
Quick question, my amp seems to be running hotter than before the tube swap. Is this normal?
post #1683 of 7300
Quote:
Originally Posted by bassboysam View Post

Quick question, my amp seems to be running hotter than before the tube swap. Is this normal?

 

It has been a long time since I have used EF 95 and EF 92 tubes, so I do not remember how hot the M8161 ran. What I can say is that it is completely normal for some tubes to run hotter than others. This is likely nothing to worry about.

post #1684 of 7300
Quote:
Originally Posted by gibosi View Post

 

It has been a long time since I have used EF 95 and EF 92 tubes, so I do not remember how hot the M8161 ran. What I can say is that it is completely normal for some tubes to run hotter than others. This is likely nothing to worry about.

To keep everything cool including myself i have a little fan above the amp that helps 

post #1685 of 7300

Getting used to the heptode 1-7 sound - sounds better and better. Looks like the bass opened up on my 6BY6 RCA's after some 40-50 hours and it became more powerful. Delicious sound...WOW!

 

Tried running RCA 1-7 and TS 6AH6WA 2-7 at the same time. (Nothing will blow up; the amp is made with two separate sections.) In theory it works, but practically something is missing. Perhaps the lack of some kind of synergistic effect of not having both channels the same. Or in other words: A person may like ice cream and steak, but together - forget it! Have to give up on two different tubes at the same time - doesn't work.

 

Listening to an early digital recording of light classical music on the Telearc label - remember those? One track has a bunch of cannon/rifle shots. The recording starts innocently with strings - and suddenly: BANG! Used to go into a HI-Fi store and ask them to play this track and crank up the volume. When the shots rang out the salesman would run up to the system and shut it off, thinking that the speakers blew. (As far as I know it never happened.)

 

Unfortunately, I cannot find a recording with the cannon shots of Freikugeln by Johann Strauss on Youtube. Anyhow, the recording I have is with the Cincinnati Pops Orchestra with Erich Kunzel from 1993. (Magic Bullets Polka)

 

For the thrill of four shots, I found this 30 second excerpt on Amazon (but MP3 does not do the recording justice):

 

http://www.amazon.com/gp/product/B001AUMD5E/ref=dm_mu_dp_trk6

 

Have fun!

post #1686 of 7300
Quote:
Originally Posted by Acapella11 View Post

 

Hi AFB, given grid 1 is furthered through pin1, how would you physically connect pin1 to pin2 for the cathode strap and then connect pin 7 (grid 3) to the pin1 socket hole in a way that isolates those two and considering that pin1 itself is still present? Without an adapter of course.

 

Ahah! Now that's a good question. Short answer is: I don't know, lol. But I do have clues -hard to actually use, but ideas nonetheless.

 

Strapping pin 1 to pin 2 without using socket hole 1 wouldn't be too hard on tubes with fairly solid pins -pins that don't break off when bent a little- you could just bend pin 1 inwards and, I guess, solder it to pin 2 close to the glass. Ugly, cumbersome, but it should work if done correctly; tube would not go very deep in the socket though but that should be OK.

 

Linking pin 7 somehow to empty socket hole 1 is a different story. The best "idea" I could come up with, short of an adapter, would be -and it's a little risky- to use a broken off pin from another tube (clean, straight and good quality), add a small bend to it (to be able to take it out of of socket hole, otherwise it would get stuck in there the second you push it in), and insert it into socket hole 1 along with the usual pin 7-1 mod wire, and the tube itself -taking care to isolate each modded pin from the next modded pin.

 

Yeah, it's difficult, but for just for testing purposes, I'd say it's pretty doable. Anyone willing to try lol? For the record, I have found that pins on US tubes are more solid and snap off more cleanly than on UK tubes, just my 2 cents.

 

I can -I might actually- try it, but on the MK IV with the brass protections, it is actually harder to "get in there" with a pair of needle pliers, and manhandle a broken pin in and out of a socket hole (yes, I know you can remove the brass parts, but I don't want to, it's what makes my unit look nice lol!). Testing this mod on a socket saver -and out of the actual MK unit- first might be a better idea.

 

Edit: But, that wasn't even why I came here to post today, I had two other things to mention, both I almost forgot about...

 

First, my Telefunken EH900S. After 13h of burn-in (strapped mode), these are excellent tubes, with great but not the greatest upper end detail. They are much more forward than what I'm used to lately, and sadly seem to be -excellent but- a bit lacking in clarity below ~500 Hz, so mids and low mids sound a bit bloated; still plenty great and better than most pentodes though, the standards have shifted too much for me to keep listening to these strapped is all.

 

Unstrapped and with grid 3 left to float away on a lonely journey away from the 4 other grids, things got much better imo. So, yes, first conclusion here -that many people had pointed out- while the strapping technique might seem "right" and seems to almost always give more detail, it doesn't always give the best sound either, and sometimes leaving grid 3 floating actually sounds more realistic. It is the case with these tubes; I got about as much upper end detail that way, better treble extension, better and larger soundstage (nothing like my strapped 5915 though!), and thinner but better and clearer mids and bass. On the floated setting, these are very very nice tubes, but I still prefer the 5915 for their boundless and speaker-like soundstage, and overall sense over "being there"; the Tele are not exactly forward when floated, but still more forward than the 5915 -like most tubes then again. Many here would love these tubes.

 

Second, I got my "Made in Holland" E91H in the mail today. Here I was expecting O-getter Philips Heerlen E91H dual labeled with a UK military CV number, exactly like gibosi's Amperex E91H, but what I got is actually much more interesting.

 

1960 Philips-Holland-Heerlen-made E91H with a D-getter (same getter as gibosi's Amperex 6687), un-pinched glass (at least not pinched like gibosi's though maybe not quite straight either), and dual labeled... IBM! So basically, Philips E91H dual control heptodes for IBM computers; which is funny, since I had just found and ordered old-world 1950 RCA-made 6BE6/6BY6 tubes specifically designed for... IBM as well!

 

Anyway, I tried these strapped right away, and they sound great -unburnt-in and strapped that is, whereas reports up to here have described these as too "sweet" strapped- like a tubier and funkier 5915. More on these after 10h of burn-in tonight!


Edited by Audiofanboy - 6/27/13 at 5:00am
post #1687 of 7300
Quote:
Originally Posted by mordy View Post

Getting used to the heptode 1-7 sound - sounds better and better. Looks like the bass opened up on my 6BY6 RCA's after some 40-50 hours and it became more powerful. Delicious sound...WOW!

 

Tried running RCA 1-7 and TS 6AH6WA 2-7 at the same time. (Nothing will blow up; the amp is made with two separate sections.) In theory it works, but practically something is missing. Perhaps the lack of some kind of synergistic effect of not having both channels the same. Or in other words: A person may like ice cream and steak, but together - forget it! Have to give up on two different tubes at the same time - doesn't work.

 

Listening to an early digital recording of light classical music on the Telearc label - remember those? One track has a bunch of cannon/rifle shots. The recording starts innocently with strings - and suddenly: BANG! Used to go into a HI-Fi store and ask them to play this track and crank up the volume. When the shots rang out the salesman would run up to the system and shut it off, thinking that the speakers blew. (As far as I know it never happened.)

 

Unfortunately, I cannot find a recording with the cannon shots of Freikugeln by Johann Strauss on Youtube. Anyhow, the recording I have is with the Cincinnati Pops Orchestra with Erich Kunzel from 1993. (Magic Bullets Polka)

 

For the thrill of four shots, I found this 30 second excerpt on Amazon (but MP3 does not do the recording justice):

 

http://www.amazon.com/gp/product/B001AUMD5E/ref=dm_mu_dp_trk6

 

Have fun!

Regarding ice cream and steak you would have to be pregnent to like that combo i guess. ITS GOOD TO BE A MAN ! And about the cannon shots i have something simmilar they call it FOR THOSE ABOUT TO ROCK BY ACDC a classic

post #1688 of 7300
Ok another observation, i noticed that the gain switches in my MKIII have virtually no effect with the CV4015 drivers. Is that expected?



edit: nevermind, i completely forgot about the jumpers. switched them over to EF92 and everything is back to normal.
Edited by bassboysam - 6/27/13 at 7:11am
post #1689 of 7300
Quote:
Originally Posted by Audiofanboy View Post

 

Ahah! Now that's a good question. Short answer is: I don't know, lol. But I do have clues -hard to actually use, but ideas nonetheless.

 

Strapping pin 1 to pin 2 without using socket hole 1 wouldn't be too hard on tubes with fairly solid pins -pins that don't break off when bent a little- you could just bend pin 1 inwards and, I guess, solder it to pin 2 close to the glass. Ugly, cumbersome, but it should work if done correctly; tube would not go very deep in the socket though but that should be OK.

 

Linking pin 7 somehow to empty socket hole 1 is a different story. The best "idea" I could come up with, short of an adapter, would be -and it's a little risky- to use a broken off pin from another tube (clean, straight and good quality), add a small bend to it (to be able to take it out of of socket hole, otherwise it would get stuck in there the second you push it in), and insert it into socket hole 1 along with the usual pin 7-1 mod wire, and the tube itself -taking care to isolate each modded pin from the next modded pin.

 

Yeah, it's difficult, but for just for testing purposes, I'd say it's pretty doable. Anyone willing to try lol? For the record, I have found that pins on US tubes are more solid and snap off more cleanly than on UK tubes, just my 2 cents.

 

I can -I might actually- try it, but on the MK IV with the brass protections, it is actually harder to "get in there" with a pair of needle pliers, and manhandle a broken pin in and out of a socket hole (yes, I know you can remove the brass parts, but I don't want to, it's what makes my unit look nice lol!). Testing this mod on a socket saver -and out of the actual MK unit- first might be a better idea.

 

 

Thanks Audiofanboy, I thought it would be a more complex operation. If we come up with a sort of fool proof way, I am in testing :)

 

Quote:

Unstrapped and with grid 3 left to float away on a lonely journey away from the 4 other grids, things got much better imo. So, yes, first conclusion here -that many people had pointed out- while the strapping technique might seem "right" and seems to almost always give more detail, it doesn't always give the best sound either, and sometimes leaving grid 3 floating actually sounds more realistic. It is the case with these tubes; I got about as much upper end detail that way, better treble extension, better and larger soundstage (nothing like my strapped 5915 though!), and thinner but better and clearer mids and bass. On the floated setting, these are very very nice tubes, but I still prefer the 5915 for their boundless and speaker-like soundstage, and overall sense over "being there"; the Tele are not exactly forward when floated, but still more forward than the 5915 -like most tubes then again. Many here would love these tubes.

 

Interesting indeed. The take home message is important really. It might come in the end down to the tube, which method sounds best.

 

Quote:
Second, I got my "Made in Holland" E91H in the mail today. Here I was expecting O-getter Philips Heerlen E91H dual labeled with a UK military CV number, exactly like gibosi's Amperex E91H, but what I got is actually much more interesting.

 

Please, do try them 2/7-strapped =)

 

Quote:
Originally Posted by mordy View Post

Getting used to the heptode 1-7 sound - sounds better and better. Looks like the bass opened up on my 6BY6 RCA's after some 40-50 hours and it became more powerful. Delicious sound...WOW!

 

Welcome in heptode land =)

 

 

Bassboysam, it is normal that EF92 tubes run hotter than EF95 tubes.

post #1690 of 7300
Quote:
Quote:
Second, I got my "Made in Holland" E91H in the mail today. Here I was expecting O-getter Philips Heerlen E91H dual labeled with a UK military CV number, exactly like gibosi's Amperex E91H, but what I got is actually much more interesting.

 

Please, do try them 2/7-strapped =)

 

Quote:
Originally Posted by mordy View Post

Getting used to the heptode 1-7 sound - sounds better and better. Looks like the bass opened up on my 6BY6 RCA's after some 40-50 hours and it became more powerful. Delicious sound...WOW!

 

Welcome in heptode land =)

 

I'll try this setting as well with the Amperexs.

 

I also ordered a pair of RCA 6BY6 since I love my EH900S so much.

post #1691 of 7300

could we use ECH84, ECH200 and 6JX8 here? Plenty high quality examples around.....

post #1692 of 7300
Quote:
Originally Posted by Nic Rhodes View Post

could we use ECH84, ECH200 and 6JX8 here? Plenty high quality examples around.....


Not without some major adapters, seeing as these are 9 to 10 pin triode-heptodes, so a pretty far cry from even the most exotic tubes we've managed to adapt...

post #1693 of 7300

I'm following in the wake here guys, and very grateful to everyone who's done all this awesome work.

 

Graduated from the regular pentodes to Tung-Sol 6AH6WA and thought the performance of the amp went up a whole class or two. Then came the first heptode, Telefunken EK90, and it got even better.

 

But not till after burn-in. For the first few hours, the sound was refined, but thin and the image set well back. I had to turn the volume up 1-2 points on the dial and even then there was energy lacking. However, after only 10-12 hours they sound like different tubes, precise focus, rich sound, if anything a little too immediate. I've not known a tube change so much so quickly. I see mab is keen on these - was this your experience? I'm looking forward to trying them strapped.

 

BTW I bought both kinds from the NOS Tube Store guy in Turkey & thought he gave good service. Good communicator, too.
 

post #1694 of 7300

Had a similar experience with the RCA 6BY6 heptodes. They sounded good, but suddenly after around 40 hours they "woke up" and the low end become much better. Wonder if others have had such experiences with heptodes?

 

Seems that many tubes need around 20 hours of burn in, some around 50 hours, and of course the champ here is the Voskhods that need 120 hours!
 

post #1695 of 7300
Quote:
Originally Posted by mordy View Post

Had a similar experience with the RCA 6BY6 heptodes. They sounded good, but suddenly after around 40 hours they "woke up" and the low end become much better. Wonder if others have had such experiences with heptodes?

 

Seems that many tubes need around 20 hours of burn in, some around 50 hours, and of course the champ here is the Voskhods that need 120 hours!
 

Thats probably why i never liked them that much because i have maybe 10-15 hours on them if i remember correctly i found them to be harsh


Edited by MIKELAP - 6/28/13 at 7:34am
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