Little Dot Tube Amps: Vacuum Tube Rolling Guide
Sep 6, 2017 at 9:16 PM Post #11,165 of 12,956

Tony51

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It should be CV4015. However, the Common Valve number, CV4015, is not at all important. It is simply an old British military inventory number for this kind of tube. And in fact, the British military considers the CV4015 and CV131 to be identical. CV4015 is the older number and CV13 is the newer.

The number that matters is M8161 (or 6065). This tube number indicates that it was considered to be somewhat better than the consumer grade EF92. Here, "better" typically means a longer lifetime, more resistance to shock and vibration and so forth. That is, it was designed to be used in more severe environments, such as a military setting or on a factor floor. And this does not mean it will sound better. After all, these pentodes were never designed for use in audio circuits.

IMO, when comparing tubes as above, it is most important to know in which factory and in what year the tubes were manufactured. Without these facts, the above comparison is relatively meaningless. Again, in my opinion.


Thank you buddy! I found them and are on order. I will soon find out if these will top my Jan5654W which are a great match to my Senn HD600.
 
Sep 7, 2017 at 1:41 PM Post #11,166 of 12,956

DylanF

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Hi Bryce.E,

The Voskhod tubes are bright sounding - don't think that they will help. In addition, they need a very long time to burn in - around 120 hours (compared to 20-50 hours for most tubes).

In my LD MKIII days we rolled tons of tubes, and one of the best driver tubes was the Yugoslavian Ei 6HM5. It is not very expensive at all, and is a good recommendation.

http://www.ebay.com/itm/EI-6HM5-EC9...051561&hash=item5d4fdb1092:g:prcAAOSwDk5UEhHk

Be aware that they have a quick heat-up feature that looks like a fiery flash when you turn on the tubes - nothing to be concerned about.

Please don't cringe, but I just ordered these and I have the LD MKII not the III, is that OK?
 
Sep 7, 2017 at 5:42 PM Post #11,168 of 12,956

DylanF

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What have you just ordered, the Voskhods or the Yugo 6HM5s? Both are good in the MKII although I think I prefer the 6HM5s (just).

The Yugo 6HM5 matched pair. Thanks for helping, I'll give them a good run on my headset/LDMKII daily on my PC.
 
Sep 7, 2017 at 6:06 PM Post #11,169 of 12,956

jon parker

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I hope this a cool place to ask this buttt... (I'll post some tube reviews later!)

Ive just got a LD 1+ It came with the wonderful Mullard 8100's
To start I plugged in my 300ohm Senn, HD 540 and it sounded phenomenal - Even my 600ohm AKG 240 Sextetts sounded amazing
BUT
When I plugged in 300ohm Senn. 560 Ovations there was a buzzing like it was clipping or > the sound a battery powered amp makes as its running out of battery <
Ive been tube rolling using just the AKG's
I just plugged in the Senn. 540's again and now they too are having the same sound issues as the 560 Ovation ??

Does anyone have a clue what is happening here?
Thanks
 
Sep 7, 2017 at 10:35 PM Post #11,170 of 12,956

mordy

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Yep, the "real" CV181, the one that was manufactured by Mullard, draws 0.9A.
I hope this a cool place to ask this buttt... (I'll post some tube reviews later!)

Ive just got a LD 1+ It came with the wonderful Mullard 8100's
To start I plugged in my 300ohm Senn, HD 540 and it sounded phenomenal - Even my 600ohm AKG 240 Sextetts sounded amazing
BUT
When I plugged in 300ohm Senn. 560 Ovations there was a buzzing like it was clipping or > the sound a battery powered amp makes as its running out of battery <
Ive been tube rolling using just the AKG's
I just plugged in the Senn. 540's again and now they too are having the same sound issues as the 560 Ovation ??

Does anyone have a clue what is happening here?
Thanks
Hi JP,

I am not familiar with the LD 1+, but my suggestion is to carefully check all connections that they are good and tight. Also to take out the tubes and clean the pins. The best method IMHO is to gently scrape them with a thin knife blade (does not have to be sharp) or similar, making sure that the pins are clean and shiny.
Sometimes hum and buzz come from a portable phone or electronic device nearby - you need to check for this too.
Good luck!
 
Sep 8, 2017 at 6:56 PM Post #11,172 of 12,956

jon parker

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Hi JP,

I am not familiar with the LD 1+, but my suggestion is to carefully check all connections that they are good and tight. Also to take out the tubes and clean the pins. The best method IMHO is to gently scrape them with a thin knife blade (does not have to be sharp) or similar, making sure that the pins are clean and shiny.
Sometimes hum and buzz come from a portable phone or electronic device nearby - you need to check for this too.
Good luck!

SOLVED:
Thanks Buddy - Quite by accident I solved it on a flash of inspiration / logical thinking!
Thought I would post the solution here as it is a very strange and misleading problem

I realized that my headphones with 1/4" jacks had no issues - Basically with small jacks with adapters, when they buzz, if I slowly turn the adapter round I reach a 'sweet' point where everything is there as it should be
Very deceptive because the issue has ALL the hallmark, actual sounds that come from faulty tubes !!

Anyhoo, in keeping with this thread, currently tube rolling BUT the Mullards are by far the 'best' although the other 3 types i've tried thus far all
have unique qualities that with certain headphones add something wonderful
 
Sep 9, 2017 at 9:26 PM Post #11,173 of 12,956

mordy

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SOLVED:
Thanks Buddy - Quite by accident I solved it on a flash of inspiration / logical thinking!
Thought I would post the solution here as it is a very strange and misleading problem

I realized that my headphones with 1/4" jacks had no issues - Basically with small jacks with adapters, when they buzz, if I slowly turn the adapter round I reach a 'sweet' point where everything is there as it should be
Very deceptive because the issue has ALL the hallmark, actual sounds that come from faulty tubes !!

Anyhoo, in keeping with this thread, currently tube rolling BUT the Mullards are by far the 'best' although the other 3 types i've tried thus far all
have unique qualities that with certain headphones add something wonderful
Hi JP.
Glad that you found the problem - can be very challenging at times......
 
Sep 19, 2017 at 10:47 PM Post #11,174 of 12,956

rexhu100

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Just gotten my RCA 5654 today, and swapped with the GE JAN-5654W that I have been using. WOW! I did not expect to hear such a big difference in sound. The bass is immediately extended. I heard many people say that RCA tubes are more 'bassy', and I has always been very skeptical, but it was no hype/myth at all! GE JAN-5654W in comparison has better clarity in the mid and high, but man these RCA tubes are awesome.

I'm just getting started in the rube rolling game. This is fun!
 
Sep 20, 2017 at 12:05 AM Post #11,175 of 12,956

Tony51

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Just gotten my RCA 5654 today, and swapped with the GE JAN-5654W that I have been using. WOW! I did not expect to hear such a big difference in sound. The bass is immediately extended. I heard many people say that RCA tubes are more 'bassy', and I has always been very skeptical, but it was no hype/myth at all! GE JAN-5654W in comparison has better clarity in the mid and high, but man these RCA tubes are awesome.

I'm just getting started in the rube rolling game. This is fun!


You might change your mind again if you give the Mullard 8161/4015 from 1969 a try. I use them with the LD mk2 and the Super Power Tubes 6H30P-i (Sovtek) (cryoset certified) plus it yielded more overall power output. I bit more than the Russian Gold Grid which is just as good, way cheaper but supplies a tad less power output. I also connected a Nobsound bass/treble PreAmp selling for 45.00 on amazon and that gave me even more power output combines. A match made in heaven. The HD600 sound fantastic and so those my Grados RS2e. I mostly keep the treble/bass flat at 12 oclock but if i need a tad of either for those mediocre recordings, it responds well. Usually no more than 2 o'clock is needed. Happy tube rolling!
 

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