Tube tasting in my Hi-Mu head - Thought I'd share

[Reeek]

I decided to dink around with tubes in my Hi-Mu head that has the air-gap OT (7 watts output through a 2x12 with two Weber ceramic Cali 12's)

I started with one of my favorites, a Hytron 6V6GTY and a Telefunken 12AT7 and a Telefunken ribbed 12AX7. It's been that way for quite awhile and sounds superb.

Then I pulled the Tele's and put in a Mullard 6201 (NIB) in place of the 12AT7. That stayed throughout.

I put an original 70's Tesla ECC803S liked it a lot more than the Tele for the 12AX7. Then I replaced the Hytron 6V6GTY with a Bendix 5192 (very rare tube). That tube sounded fantastic with the Tesla. I then stuck in an Emerson branded 6V6GT (not sure who made it, USA though) and it was the best so far. Thick, not too dark, articulate when driven and sustain to the max.

I then popped in a shield Mullard 12AX7 and that really made the difference with that Emerson. So far this is it.

The Mullard 12AX7 and 6201 stay from then on. I only mess with 6V6's now.

I then stuck an RCA black plate in and wow, they sure are up to their reputation. So far now, this is the best combo.

Then I tried a Mullard 6V6GT and believe it or not, this tube beat out the RCA by a small margin. More presence and "bloom" whatever that is. I went back and forth for awhile with the RCA BP, Emerson branded and Mullard. It was tough but the Mullard was still my favorite.

Then I decided to take one of the two pairs of Brimar CV511 6V6GTY's and split the pair to try one.

HOLY FRIGGIN MOLY!

BY FAR, this tube with the two Mullard preamp tubes is the holy grail. The presence and thickness and articulation is on par with the RCA BP, Mullard and Emerson branded but just a bit more there but then the SUSTAIN! This thing sustains like it has a pedal with the Brimars in it.

Holy Cow! What a difference.

Just thought I'd share.

 

[joel]

Cool! I think I'll power up my HiMu right now! It's got Amperex BugleBoys & RCA, into a '59 P15Q.

 

[Reeek]

Originally posted by joel
Cool! I think I'll power up my HiMu right now! It's got Amperex BugleBoys & RCA, into a '59 P15Q.

Sounds like your Hi-Mu must sing pretty nicely then

 

[Antero]

I've always wondered, Reeek - how did you come to amass the massively hardcore vintage tube collection in the first place? Must be absolute tone central in your house.

-A

 

[Reeek]

Good to see you as always, Antero

In the intelligence community, we called it saturation intelligence but in this case it was slow, steady saturation of acquired tubes. Many from Mike at KCA when items that may not be around long were available. I always try to snag tubes that may be gone soon.

Others are from select ebay sellers.

Some from a local man in Reno who was a radio head and had stashes of old tubes.

I may have as many 250 various tubes right now

By the way, I JUST ordered this 2x10 cab for the Hi-Mu and other heads I may acquire with these specs:

http://www.jdesigncabs.com/2x10.htm

Unloaded 2x10 speaker cabinet
Semi open oval removable back panel
Matching fascia on baffle
Standard black Levant Tolex
Oxblood yellow stripe speaker grill cloth
Nickel plated protective corners
Removable casters
Standard strap handle

$275 + shipping unloaded. They are in Chico, Ca and I'm in Reno so the shipping was only $18

Then I just ordered two Weber alnico Blue Pups to go into this cab. 30 watters so I can use the cab for other heads I may acquire. It will have a 60 watt capacity.

I can't wait till everything is here. The cab is 18-20 days out and Webers are usually 2 weeks before they get here. Nice pre Xmas surprise!

 

[RedMitch]

Nice to see the Hi-Mu name surface again. Its kind of the forgotten boutique amp.

I have a 6L6 SE, also with the air gap O.T. Its' two channel w/ a tone defeat switch. I play it through an old pine Fender closed back cabinet w/ Vintage 30s. About 6 months ago I installed Brimar 12AX7s and am very impressed, very chimey clean tones. I recently got 4 used RCA 6L6s and hope to sort through them soon to find the best. In any case, its' a terrific sounding amp.

I know the 6V6 was their primary product, but does anyone know how many 6L6 amps they made? They also offered a 2-EL84 amp, which I've only seen in a catalog.

Also, is there any active user/fan site?

Mitch

 

[94prs22]

Mitch,
No active fan/user sites at all that I'm aware of. The word I have from Barry is that he built just over 100 amps, I asked him how many were like yours.

I have the full 3 channel combo (3-12ax7s, 1-6v6, solid state rectifier). I currently use a Mazda 6v6 (by the way, for folks reading, the tube Reeck is referring to above is a Bendix 5992 not 5192) for the power tube, a smooth plate tele in V1 an Amperex BB in V2 and an early 70s made in Japan with Mullard tooling Mullard copy in V3. My combo has a 1971 G12H30 speaker (which replaced the original G12M reissue). As I said it has the full 3 channels (clean, gain 1, and gain 2), tone bypass, direct recording out, tube effects loop (with send and return levels, this was one of the first amps to have this), hi/lo input switch, and on/off negative feedback switch (this was also one of the first Hi-Mu amps to have this). Mine did not originally have the Air-Gap output transformer but I installed one earlier this year after I bought it. My amp was originally made for our own Dr. Rico, ordered/built in late 1993, I got it from him last year. I'm currently building another Hi-Mu single channel amp for stereo recording use and my own amp building education.
Brandon

 

[Damon]

I haven't heard a Hi-Mu but I gotta say it is a very cool-sounding name for an amp and the design sounds like it was ahead of its time.

Hey Reeek, does your Mullard 6V6GT have an acid-etched code on it? Does it by any chance say "AMERTY" on it?

P.S. I dig the Brimars too...

 

[RedMitch]

Brandon,

My amp has virtually identical features to yours with several exceptions: the 6L6 power tube & 2 channels of course, also I have a switchable tube(5Y3)/solid state rectifier but no pos/neg feedback switch. All the rest of the features you mentioned are the same. How does that feedback switch sound? I don't remember it being offered when I bought mine.

Have you ever heard one of the EL84 amps? Barry said it was basically like an AC15, but a little more aggressive.

I only spoke with Barry when I ordered the amp and when I sent it back to have the tone tweaked. He was very helpful and accommodating. I've often thought of e-mailing him to tell him how happy I've been with his amp, but he's out of the business & I had no address. If you have any contact with him in the future, thank him for me. Good guy. Rock solid amp, not a single problem with it still sounds great!

Mitch

 

[94prs22]

Mitch,
I've never heard an EL84 model, but Barry says that he probably made 6-8 of them and 12-16 of the 6L6 models. Drop me an email [email protected]. The feedback switch is pretty cool, with it off (no feedback) the amp is brighter and definitely looser with a less defined low end, with it on the amp gets a nice firm bass chunk.
Brandon

 

[Antero]

Reeek - Awesome. J Design makes great stuff. Also...

A) OMG, Reeek the secret agent?
B) The phrase "intelligence community" always makes 'em sound so friendly!

 

[Timbre Wolf]

Reeek -

Don't know how I missed this earlier, but its my kind of thread! Two questions:
- Is the "shield Mullard 12AX7" a long-plate (f91, f92 [my favorites] or mC1) or later type (I61 or I63)?
- Have you tried a Visseaux 6V6G (or any other 6V6G)?

I'd sure like to have heard your Hi-Mu as it went through the tube progression!

- T