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Little Dot I+ Tube Rolling

post #1 of 2012
Thread Starter 
Since a few days now the LD I+, a tube/transisitor hybrid is on the market.



Information from the venor is available here: NEW ! LD I+ Tube / transistors mixed Headphone Amp..

Further discussion can be found here

This amp has the unique ability to be used with three distinct tube varieties:

5654
6JI, WE403A/B, M8100, CV4010, EF95, 6AK5
Miniatur-7-Pin-Base RF miniature pentode, 6.3V heater


5654W


6AK5


408A
Miniatur-7-Pin-Base B7G, 20V, 50mA heater


Jan NOS (Phillips)


EF92
CV131, EF91, CV138, M8161
Miniatur-7-Pin-Base B7G, 6.3V heater


6AM6 (EF91)


EF92 (left Mullard, right Phillips)

From what I could see the 5654 and the 408A have the same pin out but different heater voltage and the EF92 has a different pin out to the other two.

I am still waiting for my LD I+, but I already ordered a few tubes:

6J1 stock
EF 95 (6AK5W) Siemens
6Zh1P-EV/6J1P-EV VOSHOD

6028 (408A) Philips ECG

EF 91 Siemens/Mullard
6AM6 CEI
EF 92 (CV 4015) Philips

What other tubes are out there, what tubes do you have and already used, which ones do you like / dislike?
post #2 of 2012
A good and trusted source for Little Dot tubes would be Yen Audio on ebay, all of the tubes sold by YA are matched pairs which in my experience is very important in terms of portraying an accurate and believable soundstage. It looks like they're stocking some 408A tubes just for the I+. Highly recommended place to start looking at LD upgrade tubes if you're just starting out in the tube amp hobby.

http://stores.ebay.com/Yen-Audio_Lit...QQftidZ2QQtZkm
post #3 of 2012
Quote:
Originally Posted by mapstec View Post
From what I could see the 5654 and the 408A have the same pin out but different heater voltage and the EF92 has a different pin out to the other two.
The EF92 and 5654 have the same pin out the difference is that the EF92 draws 200mA of plate current while the 5654 draws 175mA. This gives the EF92 a little more gain and (in theory) a more linear top-end response.

- DoA
post #4 of 2012
Gents, from reading between the lines of previous threads the Mullard M8161 appears to be a tube worth investigating with the LD I+. One (UK) eBay seller has both the old logo and new(er) logo varieties: is there any difference, and if so, which is the better for the I+.

eBay UK Shop - COLOMOR VALVES TUBES COMPONENTS: Audio Tubes Valves, Radio Tubes Valves, Collectible Vintage Tubes

K.
post #5 of 2012
Thread Starter 
Quote:
Originally Posted by Dept_of_Alchemy
The EF92 and 5654 have the same pin out the difference is that the EF92 draws 200mA of plate current while the 5654 draws 175mA. This gives the EF92 a little more gain and (in theory) a more linear top-end response.

- DoA
Doesn't that imply the same setup? If it is just that the circuit needs to be able to deliver more current? Then why do we need to jumper between the tubes?

Can somebody please comment?

What other tubes are available for the I+?
post #6 of 2012
There are a lot of different tubes that can be used. The EF95 family has the biggest selection in terms of variants (EF95/5654/CV4010/M8100/6096/403A/B/6J1...

I recently received my I+ and have it set to the EF92/EF91 family. Have not changed any tubes yet, burning it in some.

With my SE, I have rolled in many, many tubes, particularly in the EF95 family. I have tried various 6AK5W, 5654, 6096, EF95, M8100, 403A etc. Not one combination has sounded bad.

I+
Jumper setting #1- EF95 etc....
Jumper setting #2- EF92/91 etc...
Jumper setting #3- 408A/6028.....

Heater and sensitivity are different between the families...
post #7 of 2012
I'm very much enjoying my I+ with same russian tubes (6Zh1P-EV) that are in my MKIV SE.

I'll also have some Amperex 5654's, GE 5-stars and SE's stock M8100's.
post #8 of 2012
The 408A looks like a great sounding tube on paper, I can't wait for this thread to get started. I'm about to order a I+ just to try it out...
post #9 of 2012
... just picked up a pair of WE 408As and that's what's going in mine ... hopefully when it arrives this weekend .... also picked up a set of 32 ohm Denon AH-D1001s - I'm hoping it's a nice match!
post #10 of 2012
Thread Starter 
My amp should be here tomorrow
With the various tubes to arrive over the next week.

Always remember that forming an opinion about a tube takes time.

You can not critique a tube until it has burned in, and since we are talking NOS tubes here I suggest a minimum of three days at 8hours.

I have a tube amp using one 6922 here at my desk right now, and the positive (!) difference in SQ the last few hours have made (from less then 10h to like 15h) on the 7308 in there is astonishing!
post #11 of 2012
My LD 1+ arrived yesterday...luckily my Tung-sol and Sylvania 408a's arrived last week as i ordered the amp without any tubes ....I have been listening for about 8 hours so far and am more than impressed right out of the box. Great soundstage, fast and lots of detail....Very musical..This is the best bang for buck i've had since joining this forum. Can't wait till the amp and tubes have a few more hours on them...Have alot of different EF95 and EF92 tubes but will probably be awhile before I try them as these 408a's are very very nice. Just enjoying the music for now...
post #12 of 2012
Quote:
Originally Posted by Killahertz View Post
Gents, from reading between the lines of previous threads the Mullard M8161 appears to be a tube worth investigating with the LD I+. One (UK) eBay seller has both the old logo and new(er) logo varieties: is there any difference, and if so, which is the better for the I+.

eBay UK Shop - COLOMOR VALVES TUBES COMPONENTS: Audio Tubes Valves, Radio Tubes Valves, Collectible Vintage Tubes

K.
Right, just plumped for a pair of old logo M8161. My first real foray into tube rolling, so i'm really looking forward to seeing how they react in the I+, and also how they stack up against the current Ediswan EF92.

PS: Am I right in thinking that the M8161 are essentially the same 'family' as the EF92, so will plug straight in with no need to change internal set-up?
post #13 of 2012
Quote:
Originally Posted by Killahertz View Post
Right, just plumped for a pair of old logo M8161. My first real foray into tube rolling, so i'm really looking forward to seeing how they react in the I+, and also how they stack up against the current Ediswan EF92.

PS: Am I right in thinking that the M8161 are essentially the same 'family' as the EF92, so will plug straight in with no need to change internal set-up?
That is correct...EF92/M8161 EF91/CV138

I threw in some Mullard EF91. The EF91 is a picky tube and I believe some had hum problems with it on the SE, however, the Mullards on the I+ are dead quiet.

A bit warmer than the Ediswan EF92 but still not losing that Grado punch. I have also noticed better instrument separation with the EF91. I have a pair of JAN 6028s next in line. Going to shut it down in a few, let it cool down, switch jumpers for the 408A and enjoy...

Good Times...
post #14 of 2012
Quote:
Originally Posted by HeatFan12 View Post
That is correct...EF92/M8161 EF91/CV138

I threw in some Mullard EF91. The EF91 is a picky tube and I believe some had hum problems with it on the SE, however, the Mullards on the I+ are dead quiet.

A bit warmer than the Ediswan EF92 but still not losing that Grado punch. I have also noticed better instrument separation with the EF91. I have a pair of JAN 6028s next in line. Going to shut it down in a few, let it cool down, switch jumpers for the 408A and enjoy...

Good Times...
Thanks for that. I can't find the 408A locally (UK) as yet, but i've a few options for the time being
post #15 of 2012
Thread Starter 
I am stupid.... no really I am ....

I got my LD I+ this morning, and of course could not wait...
So I opened it up and changed the settings to allow me to run the 408A (in my case the Jan 6028).

I complained about the fact that the unjumpered positions do not include the spare jumpers... but I was wrong: The jumpers are included with the Audio cable - silly me...

Anyway, the 6028 sound good for the early hours, the amp is not geeting too warm - call me happy!
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