JAS Audio Bravo 2.3 6C33-B Class A SET integrated

Bunky · June 11, 2011, 07:35:36 PM

I have replaced the 5Z3P rectifier tubes with some 5U4G Sovtec's that were actually made by Svetlana in St Petersburg.i have NOS Russian Military 6J4P input tubes coming from across the pond and i have a Quad of NOS Winged C 6C33-B Svetlana's on the way from Mother Russia which are very rare and were made in the mid to late 1960's. these 6C33-B's were not only used in the Russian MIG 25 FOXBAT fighter jet. that crazy guy Rommy the Cat has a picture on his website of these tubes mounted inside of a Soviet Cruise Missle

richidoo · June 11, 2011, 07:58:35 PM

That is cooool!!!
http://www.romythecat.com/GetPost.aspx?PostID=9434

Thanks William

Shane there is some great 6C33 discussion on the page linked above.

tmazz · June 11, 2011, 10:18:59 PM

Quote from: Bunky on June 11, 2011, 07:35:36 PM
these 6C33-B's were not only used in the Russian MIG 25 FOXBAT fighter jet. that crazy guy Rommy the Cat has a picture on his website of these tubes mounted inside of a Soviet Cruise Missle

Of course, that way the jet and the missile would both still function ofter the magnetic pulses emitted by the bombs in a nuclear war had wiped out all of the semi-conductors.

Bunky · June 12, 2011, 06:15:51 AM

Electro magnetic pulse will fry transistors leaving the bulk of western fighter jets ,bombers and missles stranded and Commie tube equipped aircraft would be immune to this and in theory be able to still function to have a second strike capability. did the guys with the stars and bars at the Pentagon know this ? maybe it was just cheaper for thier defense contractor cohorts to build solid state avionics to maximise profits instead of using tubes that are immune to EMP. this is just another of many reasons why TUBES RULE !

rollo · June 12, 2011, 06:55:27 AM

Quote from: Bunky on June 12, 2011, 06:15:51 AM
Electro magnetic pulse will fry transistors leaving the bulk of western fighter jets ,bombers and missles stranded and Commie tube equipped aircraft would be immune to this and in theory be able to still function to have a second strike capability. did the guys with the stars and bars at the Pentagon know this ? maybe it was just cheaper for thier defense contractor cohorts to build solid state avionics to maximise profits instead of using tubes that are immune to EMP. this is just another of many reasons why TUBES RULE !

Coluld be, my bet it was the enviormental crowd who regulated out tube now lightbulb manufacturing here.

charles

charles

tmazz · June 12, 2011, 08:22:32 AM

My comment was rather tongue-in-cheek, but the MiG-25 was designed in the early 1960s when solid state was still in it's infancy and tubes were still the technology of choice for many applications, especially in some of the high power RF and radar circuits used in the MiGs.

As for the design of our own aircraft the changeover to solid sate devices and ultimately IC based circuitry was not driven by cost bit rather the desire for more advanced capabilities in terms of aircraft control, navigation and radar, communications and weapon systems. None of the advances systems in the current vintages of our military aircraft would be practical (or maybe even possible) using all tube designs because of size, weight and heat issues. I dare say the if the electronics of a current F-15 was built using all tubes you would have trouble fitting it all in a single aircraft hanger, never mind a single aircraft.

hometheaterdoc · June 13, 2011, 08:42:57 AM

Quote from: richidoo on June 11, 2011, 07:58:35 PM
That is cooool!!!
http://www.romythecat.com/GetPost.aspx?PostID=9434

Shane there is some great 6C33 discussion on the page linked above.

Thanks Rich... I'd already read everything on that website before starting down the path with Sol on the amps... I'll be very interested to hear what Sol's design is going to sound like whenever it finally gets built... he said he was going to go back to it for the first time in months after I left his place last night.... with the amount of changes made to it during this prototype stage, it hardly resembles the original amp we conceived... although the autobias circuit for it is still seriously cool..... and having every power supply be seriously fully regulated is definitely going to make it sound different than all the other commercial stuff I've been trying out....

richidoo · June 13, 2011, 09:02:09 AM

Quote from: hometheaterdoc on June 13, 2011, 08:42:57 AM
with the amount of changes made to it during this prototype stage, it hardly resembles the original amp we conceived... although the autobias circuit for it is still seriously cool..... and having every power supply be seriously fully regulated is definitely going to make it sound different than all the other commercial stuff I've been trying out....

Agreed! I think the whole gang is looking forward to the unveiling. I know he's been working on it in the last few months cuz I cut some new tube holes a few weeks ago and talked to him about new ideas just before that.

It's coming!

hometheaterdoc · June 13, 2011, 12:59:05 PM

yeah... we talked through a bunch of stuff last night as we were trying to sort out all the issues with some other 6C33c monoblocks I bought that showed up damaged courtesy of Fedex...

getting back to the topic of this thread... I'd love to give the amps that Bunky bought a whirl and see what they sound like... I just don't have any speakers that they'd work on... I need more juice than these provide...

Bunky · July 16, 2011, 12:56:09 PM

i misplaced the manual for my JAS Bravo 2.3 and i went to the JAS Audio website to look at the manual and i noticed that the rectifier for the 2.3 was a 5AR4 ? mine uses a 5Z3P rectifier tube. i looked at the manuals list and noticed a manual for a Bravo 2.3 SE and when i looked at the PDF i noticed that it uses the 5Z3P and is rated @ 18 wpc. the only differences i can tell from the manuals are that the 2.3 is rated @15 wpc and uses the 5AR4 and the 2.3 SE uses the 5Z3P and is rated @ 18wpc. so my amp is in fact a Bravo 2.3 SE

richidoo · July 16, 2011, 01:18:56 PM

Instant upgrade!

Does it sound better now?

Bunky · July 16, 2011, 02:39:52 PM

i feel better does that count ?

it is dead quiet at full volume thanks to the dual chokes in the right and left channels. it has a very stout power supply for a CHI-FI product and rolling the rectifier tubes makes a big difference. i am currently running the EH 5U4GB which is a copy on a vintage RCA Blackplate. i have some other NOS rectifiers on order. this little 54 lb amplifier sounds even better than it looks

richidoo · July 16, 2011, 02:46:59 PM

chi-fi - funny!

rollo · July 18, 2011, 07:53:50 AM

Quote from: BobM on May 31, 2011, 06:05:32 PM
Pretty. Do you think it might drive my 83db inefficient Apogees?

No but I bet the Bryston SST2 series amps would blow you away. Still cannot get over how the all Bryston system sounded. Especially with the Lenehan ML-1 Sing. speakers. Even the Carver Amazing speakers sounded the best they ever had.

charles
SMA [ dealer for Lenehan]

Bunky · August 08, 2011, 07:13:19 PM

OK i rolled in a pair of US made 1961 GE 5U4GB and i liked them better than the various Chinese and Russian varients i have experimented with.today i rolled in a pair of highly desireable circa 1944 RCA blackplate Coke Bottle 5U4G and i am very happy with these rectifier tubes in this amplifier

.i bought these on Ebay from greengirl for $100.00 for the matched pair.these are somewhat hard to find so i will try to find some spares to stash away