[Phantaminum]

I see the issue. The single red lead from the rectifier socket to the reservoir cap is connected to pin 7, but it should be connected to pin 8, the same as one of the yellow rectifier heater leads. Also the resistor leads from pin 3 and very close to pin 4, I would bend them away to be sure they don't cause a short.

If I could kiss those eyes @L0rdGwyn . That did the trick.

Now to chase down the channel imbalance issue when I flip the impedance switch.

 

[mchuckp]

Anybody out there from the US who has built the Aegis have spare hardware (nuts, bolts, washers, etc) that you'd sell me? I've checked all my local stores and nothing. The Amazon link from the BOM provides everything that I need but then I end up with many 100's of extra parts which seems wasteful and ends up costing me close to $60. Figured maybe someone here may have bought that set or similar and would like to help me out and recoup some of their costs. If not, I'll order from Amazon. Figured it was worth asking. PM me if you can help.

Thanks!
Mike

 

[mattiastomas]

So I've recently been running Brimar 5R4GY, RCA 5691, and Mullard EL38 combo. I think this is my favourite combo by far.

Have only had this set for 2 days now, but oh my! It's an amazing combo! Can only imagine that it gets better with some burn in.

The clarity and separation from the EL38s are very apparent. Guitars and orchestral instruments timbre have a very good sense of timbre and weight behind them.

Its a killer combo with the Atrium Closed. Still getting a feel for the Caldera so not 100% comfortable with its sound signature yet.

Now I just gotta save up for spares

P.S. Thanks @Toonartist for the tube suggestions!

 

[Toonartist]

That's great to hear.... the clarity that combo offers is something else! The EL38 seem to have quite a range from lows to highs and imaging, separation. I just love the depth you get from them. For classical it's like your sat amongst them. I find they're great with both the Elites and AC. The AC with the Auteur Suede solids sound really good with that combo as well... it's like a spherical soundstage but very precise imaging.

If you feel you need to extend soundstage or lighten it further with the AC, try an RCA 5R4GYB. That combos a bit much for the Elites though.

 

[L0rdGwyn]

If I could kiss those eyes @L0rdGwyn . That did the trick.

Now to chase down the channel imbalance issue when I flip the impedance switch.

That likely means there is a short or a bad solder joint on the ELMA switch PCB.

 

[Kdot]

That's great to hear.... the clarity that combo offers is something else! The EL38 seem to have quite a range from lows to highs and imaging, separation. I just love the depth you get from them. For classical it's like your sat amongst them. I find they're great with both the Elites and AC. The AC with the Auteur Suede solids sound really good with that combo as well... it's like a spherical soundstage but very precise imaging.

If you feel you need to extend soundstage or lighten it further with the AC, try an RCA 5R4GYB. That combos a bit much for the Elites though.

I snagged a RCA 5R4GYB, and now I like the RCA 5691 + EL38 much more. Especially on my 6xx--- on the 8xx it is a little too spaced out. Waiting for my Brimar to come in from the UK!

 

[goldwerger]

After having the EL37 in since nearly the get-go...

... first pair of EL38 are in (brown base, trough getter, 1956)

First impression - they sound nearly identical. So, as far as value for the money, the EL38 are a much more affordable option to get close to the EL37 sound.

Second impression - and, I may be imagining it, but I think the EL38 is a touch (a sliver of a portion of a flock of a hair) more incisive; and, by the same measure, the EL37 is a touch warmer and sweeter in the mids. The adjectives are as ambigious as my initial impressions. I'm not sure I'd pass an A/B test. I think I'll prefer the EL37 for vocals, acoustics, jazz (which is most of my listening) and the EL38 to more bass-heavy pop, R&B, and other music with rhythmic bass (which I listen to as well).

Will share more if I get a better sense of it..

 

[mchuckp]

I’ve been looking up 37s and 38s today and noticed the price difference. Know if there are different variations of the 38s to look for or avoid? Do they take an adapter or can it be plugged right into an Aegis?

I’m starting my build soon. I have some gold lion kt88s from another amp i no longer have. Thought maybe those and the 38s would be a great starter pack to see what floats my boat. Guessing quite different based on what I’ve read.

 

[Toonartist]

After having the EL37 in since nearly the get-go...




... first pair of EL38 are in (brown base, trough getter, 1956)




First impression - they sound nearly identical. So, as far as value for the money, the EL38 are a much more affordable option to get close to the EL37 sound.

Second impression - and, I may be imagining it, but I think the EL38 is a touch (a sliver of a portion of a flock of a hair) more incisive; and, by the same measure, the EL37 is a touch warmer and sweeter in the mids. The adjectives are as ambigious as my initial impressions. I'm not sure I'd pass an A/B test. I think I'll prefer the EL37 for vocals, acoustics, jazz (which is most of my listening) and the EL38 to more bass-heavy pop, R&B, and other music with rhythmic bass (which I listen to as well).

Will share more if I get a better sense of it..

I wouldn't argue with that.

Going from cooler to warmer I rate them like, EL38, EL37 & EL39. They all seem to have the same inners and have a similar character with varying degrees of warmth and clarity and size of soundstage. This is great if you have a number of headphones that vary in brightness or sounding too thick. Just mix and match. Not sure what makes these all sound different as the insides o look identical!.

When the EL38's settle down, you may also find the staging, imaging improving. I find these characteristics to be the last things to become apparent when running in a tube... or cables etc. Not sure why.

@mchuckp There seem to be two main variants. Trough (or box) getter & Double Halo. The trough getters would appear to the be the older tubes. All the ones I have have been dated pre 1955 with a tube code of 1326 alongside the date code but I've heard they continued after 1955 but most likely with a HM1 tube code. They also have a black getter flash (or near black). Apparently a different process was used at that point and it isn't a sign that a NOS tube has been used or is duff. There can even be some soot marks on the anode plate from the application process.

The double halos seem to be from the 60's and have the more common bright silver getter flash and HM1. I haven't ran the trough getters for any length of time yet to be able to say if there are any differences but from the couple of hours of initial testing, they sounded pretty much the same as the double halos. Both variants give off quite a strong blue glow initially when new (pop the room lights off to see it at night). This fades once they've been ran in for a couple hundred hours or so.

I haven't seen any other variants yet.

 

[goldwerger]

All the ones I have have been dated pre 1955 with a tube code of 1326 alongside the date code but I've heard they continued after 1955 but most likely with a HM1 tube code.

My brown base trough getter are 1956 based on code B6J — they do actually also have the Hm1

My black base double halllo getters are 1966 based on code BL71 - also with HM1 code

What’s you know what is the meaning of Hm1?

Also, I guess in theory the black bass code could mean 1976, 1986.. only way to know is whether those variants were or were not made in later year(?)

 

[Toonartist]

My brown base trough getter are 1956 based on code B6J — they do actually also have the Hm1

My black base double halllo getters are 1966 based on code BL71 - also with HM1 code

What’s you know what is the meaning of Hm1?

Also, I guess in theory the black bass code could mean 1976, 1986.. only way to know is whether those variants were or were not made in later year(?)

I haven't found anything to suggest a change of design, just a change in record keeping that took place in 1955. This is a wild guess but they may have wanted a system that would offer a lot of variations with minimal number of characters due to more and more tubes being designed and made rather than relying on numerical code only. Just a guess though.

My 1952 trough getters are black base though so I'm not sure if the base colour means anything in this case. Out of my double halos, only one of the six has a black base and that was made in Jan 1959. Maybe they ran out of black for a while

Approx dating of Mullard Tubes
Mullard New logo 4 digit code = 1970's
Mullard Old logo 4 digit code = 1960's
Mullard Old logo 3 digit code = 1950's

Is that tube definitely BL71? B6J is Oct 1956

Normally Mullard codes go in this order - Factory (alphanumeric) / Year (numeric) / Month (alpha) / Week (numeric - 1960's onwards). I've never seen an EL38 made in the 70's or later yet (new logo) but that doesn't mean there weren't of course. Link to Mullard tube dating site

So, HM1 B9A = EL38 Blackburn factory Jan 1959 and HM1 B6K3 = EL38 Nov 1966 (3rd Week).

Edit - the 1326 tube code for the EL38 may well date back to the code system first introduced in the 1930s as the date code is also slightly different for these very early tubes as well.

 

[mattiastomas]

Both variants give off quite a strong blue glow initially when new

Interesting. Mine doesn’t seem to have any blue glow at all.

 

[Toonartist]

Interesting. Mine doesn’t seem to have any blue glow at all.

At night with no room lights on? Sometimes it's easier to see when you take a pic. With no lights on take a photo... probably have to rest against the amp or something as it will be a long exposure... its the long exposure that brings it out more. I'll find a photo in a bit.

Probably doesn’t mean much if it doesn’t just what I noticed with two pairs of mine. The photo below is exaggerated because of a very long exposure.

This one less exaggerated

 

[goldwerger]

Is that tube definitely BL71?

Sorry type JT’s B7L1.. Blackburn from Dec-1967..

Any idea what the Hm1 stands for?

Mine doesn’t seem to have any blue glow at all.

Mine neither (at least first pair I tried)

 

[Toonartist]

Sorry type JT’s B7L1.. Blackburn from Dec-1967..

Any idea what the Hm1 stands for?



Mine neither (at least first pair I tried)

There you have it.... mine are the anomaly

No idea... probably means something to a bean counter or stock keeper from back in the day. Probably just a random assigned tube indicator. Each tube has it's own number / identifier.