Little Dot Tube Amps: Vacuum Tube Rolling Guide | Page 384 | Headphone Reviews and Discussion - Head-Fi.org

kvtaco17 · Apr 5, 2014 at 8:58 AM

I should rewire mine with 750kcmil... I could use scrap from work LMAO

TrollDragon · Apr 5, 2014 at 9:07 AM

kvtaco17 said:
I should rewire mine with 750kcmil... I could use scrap from work LMAO

I've stripped 4/0 chunks for the copper before... I'd love to have your 750 scraps.

I just love wire you have to cut with a Milwaukee Sawzall.

kvtaco17 · Apr 5, 2014 at 9:24 AM

trolldragon said:
I've stripped 4/0 chunks for the copper before... I'd love to have your 750 scraps.

I just love wire you have to cut with a Milwaukee Sawzall.

4/0 is little cable in my line of work lol

We normally use 350-1000... BUT the customer keeps the scrap... #thesearesaddays

Oskari · Apr 5, 2014 at 2:01 PM

gibosi said:
The BRIMAR date code is "4F2", where 4 equals week, F equals month, and 2 equals year, so the year of manufacture could be 1952, 1962 or even 1972. However, with a D-shaped getter, I don't think it is as late as 1972. On the other hand, I am not sure this tube was even available in 1952, so my best guess is 1962.

That was my initial thinking, too. Now I'm not sure. The label style is certainly too old for 1972, but is it too old also for 1962? I tried to find photos of matching tubes with additional military labels (unambiguous date codes!) but this proved difficult. With enough patience this could be done.

http://www.r-type.org/exhib/aaa0626.htm tells us that the type first appeared in a 1953 Brimar manual. I then found this:

http://www.ebay.co.uk/itm/Brimar-13D3-CV2212-KB-FD-black-plate-ECC802s-ECC82-wide-square-getter-pair-rare-/291075287902?orig_cvip=true

The photos show what must be experimental CV2212s with 2F2 date codes – and HG military date codes. That's July 1952. This agrees nicely enough with June from 2F2. Also note that, like your tube, the tubes have no type codes that usually go together with date codes. They do have the Footscray [military] factory code FB. Otherwise I've only seen Rochester codes, earlier FD and later AD.

In short, I don't know where and when your tube was made.

gibosi · Apr 5, 2014 at 2:30 PM

oskari said:
http://www.ebay.co.uk/itm/Brimar-13D3-CV2212-KB-FD-black-plate-ECC802s-ECC82-wide-square-getter-pair-rare-/291075287902?orig_cvip=true

The photos show what must be experimental CV2212s with 2F2 date codes – and HG military date codes. That's July 1952. This agrees nicely enough with June from 2F2. Also note that, like your tube, the tubes have no type codes that usually go together with date codes. They do have the Footscray [military] factory code FB. Otherwise I've only seen Rochester codes, earlier FD and later AD.

Comparing my tube to those, as best I can tell from the photo, the construction appears to be identical. Also, I overlooked two more characters printed in red on the back of the tube: A 3.

Nic Rhodes · Apr 5, 2014 at 2:35 PM

The valve was certainly around by 1953 but not released by 1951 so 1952 is a real possibility.

Oskari · Apr 5, 2014 at 3:20 PM

nic rhodes said:
The valve was certainly around by 1953 but not released by 1951 so 1952 is a real possibility.

gibosi said:
Comparing my tube to those, as best I can tell from the photo, the construction appears to be identical. Also, I overlooked two more characters printed in red on the back of the tube: A 3.

Looks like you might have a very early 13D3 there. (I don't know what the red characters purport to tell.)

i luvmusic 2 · Apr 5, 2014 at 4:36 PM

gibosi said:
The connections look good to me. As to the adequacy of 18awg or 22awg, someone else will have to weigh in.....

Thank You!

trolldragon said:
According to the chart #18 will handle 16A. You could probably get away with a 20 or 22 AWG but if your power supply is fused at 12 or 15A, anything lower than 18 would glow red and burn before the fuse blew.

So I would use the 18AWG just incase you ever had a short it would pop the fuse in the power supply.

If the powersupplys fuse is replaceable, you could put an 6 or 8A in place of what is there and use lower gauge wire.

18 is not that bad to work with so go with it, safety first.

AWG wire chart.
www.powerstream.com/Wire_Size.htm

Thank You!

gibosi · Apr 5, 2014 at 4:59 PM

nic rhodes said:
The valve was certainly around by 1953 but not released by 1951 so 1952 is a real possibility.

oskari said:
Looks like you might have a very early 13D3 there. (I don't know what the red characters purport to tell.)

Thanks for your help guys!

So I will put in my notes that this tube was quite likely manufactured in 1952, factory unknown.

I spent a couple hours with this tube yesterday evening and it reminds me of other Brimars I have heard, with a strong bass, warm mids and somewhat subdued highs, a pretty good match for my HD700s. And after a half hour or so, I stopped listening to the tube and began to listen to the music, a very nice tube. Recommended.

gibosi · Apr 5, 2014 at 5:26 PM

Mordy,

If you are still looking for headphones, some to consider:

Beyer DT770 250ohm - $125 shipped (MFR-Used Restock Model).

http://www.fullcompass.com/product/436749.html?utm_source=googleps&utm_medium=shopping&utm_campaign=googleps&gclid=CK2zsqWAyr0CFUoV7AodEHUAxQ

Also...

www.razordogaudio.com extended their warehouse sale until April 15th:
Items below are 22% off with PROMO CODE --- WAREHOUSE.
2. ALL AIAIAI products
3. ALL KEF products
4. ALL AKG consumer AND pro products
5. ALL Harman Kardon
6. ALL JBL inventory
7. ALL FOSTEX
8. ALL Beyerdynamic

And

25% off select headphones at Sonic Electronix including low end Grados (SR60s, 80s, 125s), some AKGs, Senn Momentum On Ears, 380 Pros, Westone UM1s, etc.

Search using Headphones040514 as your keyword,
use 25HEAD for the Coupon Code

i luvmusic 2 · Apr 5, 2014 at 5:59 PM

These will be my new Power supply/adapter for LD 1 and MK III when it's done.I can't wait for that speed boat from Chinada delivering my parts if that speed boat is not here in 2 weeks i will probably butcher one of my Amp and put it inside these case or i will learn how to read schematics and buy parts so i can build an amp instead of just power supply/adapter that is why i leaved the faceplate blank and did not solder any wires so i can decide what should i do with it later.The top plate is recycled from a old electronics(free)The faceplate(free)The two sides Wood cutoff from lumber yard $4 (cheap person) plus sockets and screws $15 that's how much it cost me and labour free i enjoyed it.

Rossliew · Apr 6, 2014 at 12:02 PM

mordy said:
Hi i luvmusic2,

There are actually 2x2 adapters. Here is the first one that allows you to put an octal tube into the Little Dot MKIII.
http://www.ebay.com/itm/221065459067?_trksid=p2055120.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

However, the decorative rings around the tube sockets do not allow these adapters to go inside the socket since the adapters are too wide to fit inside the ring. For this we need an extender or socket saver:

This set fits inside the ring. http://www.ebay.com/itm/2PCS-9-PIN-vaccum-TUBE-SOCKET-SAVER-FOR-12AX7-12AU7-ECC82-ECC83-tube-audio-amps-/251350602537?pt=Vintage_Electronics_R2&hash=item3a85a9d329

Spending around $35 incl shipping for these four adapters allows you to use any 6SN7 tube (and 6SL7) in your LD MKIII. These tubes outclass the 6N6P family of tubes and to boot are plentiful and very inexpensive.

There is a lot of hype about the 6SN7 tubes, and certain types command very high prices. IMHO I would not bother with these but instead buy any garden variety Sylvania or RCA tube. Just plug them in and enjoy delicious, full bodied sound! In addition, these tubes are well built and are supposed to last a long time.

Another added bonus I noticed is that my LD amp does not even break out in a sweat with these tubes and the amp is cool to the touch. It has to be added though that I am using another 6SN7 as driver with it's own power supply. The tubes run hot, but the amp is not even warm.

And then there is the ephemeral Blue Light......

Hi, would these adaptors allow the use of 6AS7 tubes in the LD Mk III ?

Sorry, a noob here with the LD and also tube rolling...appreciate your advice on the various types of tubes which I can use with the adaptors in your picture above (thanks for the link to eBay - will purchase them to try out)

i luvmusic 2 · Apr 6, 2014 at 12:13 PM

Using a 6AS7 on LD without external power supply might suck out the life of your LD.I'am no expert it's just my opinion...

Rossliew · Apr 6, 2014 at 12:17 PM

Thanks for the advice! LOL thankfully I didn't go crazy and start buying all types of tubes...what about those unique tubes which Gibosi uses in his amps? Where can one find an adaptor to match them to the LD mk III?

i luvmusic 2 · Apr 6, 2014 at 12:23 PM

Picked up a pair of 6CG7 for $2(pair)didn't think it works because vendor said they are not tested.I just tried now(Driver tube) and they are working they sound better than my 6N6P-i driver tubes.

Latest Thread Images

kvtaco17

Headphoneus Supremus

TrollDragon

Headphoneus Supremus

kvtaco17

Headphoneus Supremus

Oskari

Headphoneus Supremus

gibosi

Headphoneus Supremus

Nic Rhodes

500+ Head-Fier

Oskari

Headphoneus Supremus

i luvmusic 2

Headphoneus Supremus

gibosi

Headphoneus Supremus

gibosi

Headphoneus Supremus

i luvmusic 2

Headphoneus Supremus

Rossliew

Headphoneus Supremus

i luvmusic 2

Headphoneus Supremus

Rossliew

Headphoneus Supremus

i luvmusic 2

Headphoneus Supremus

Users who are viewing this thread