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Paraglow 2a3 SET

99.247.46.15

Posted on January 29, 2017 at 06:36:13
audiophilewannabe
Audiophile

Posts: 503
Location: toronto
Joined: July 19, 2004
I just got a pair of older Bottlehead Paraglows, Do they all come with magnaquest transformers or were they optional upgrades then? How can I tell if mine has it? Why did they stop selling the kits for them? How do they differ from the newer kits available? Thanks in advance,

 

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RE: Paraglow 2a3 SET, posted on January 29, 2017 at 07:09:15
RPMac
Audiophile

Posts: 275
Location: So. Mississippi
Joined: January 3, 2005
Yes, came with all magnequest iron
Replaced by Paramount

 

RE: Paraglow 2a3 SET, posted on January 30, 2017 at 14:03:06
audiophilewannabe
Audiophile

Posts: 503
Location: toronto
Joined: July 19, 2004
Thanks .... are they auto bias? Do I need to do anything if I tube roll? What's a good set of 2a3 tubes for these amps... it came with sovtek and it seems be be very good, but would like to try other makes.

 

Yes, they are cathode biased, posted on January 30, 2017 at 15:01:59
Frihed89
Audiophile

Posts: 15121
Location: Copenhagen
Joined: March 21, 2005
No adjustment. There is a lot of debate about the "best" 2A3. Most of the popular current production tubes are listed on the URL below. Ones that are not there, namely 3 different types of Emission Labs (EML) 2A3 tubes , can be found at JAC music.

You really should search or ask the tube question on the Bottlehead forum.

 

RE: Yes, they are cathode biased, posted on January 30, 2017 at 16:59:03
RPMac
Audiophile

Posts: 275
Location: So. Mississippi
Joined: January 3, 2005
Frihed is correct that you will get better answers on the BottleHead forum under "Legacy Products" from the designers. There were a couple of variations...what is your driver tube?

It is direct-coupled with a strong turn-on. Not all my old stock tubes liked it, but coil spring Sylvania did well. New production tube didn't seem to have a problem. EML tubes weren't recommended. Again, BottleHead is the best place for accurate answers.

OPTs were EXO-035 or 036...one is 8 ohm, the other 16 ohm(I forget which are which, but they are nickel )

Good amps worth using!

 

No, they are not cathode biased, posted on January 30, 2017 at 17:37:25
Paul Joppa
Industry Professional

Posts: 6676
Location: Seattle, WA
Joined: April 23, 2001
At least, not in the normal meaning of the phrase. They are direct coupled.

 

RE: Paraglow 2a3 SET, posted on January 30, 2017 at 18:05:00
Paul Joppa
Industry Professional

Posts: 6676
Location: Seattle, WA
Joined: April 23, 2001
The Paraglow was replaced by the Paramount, as RPMac said below. The Paramount could be built as either a cap-coupled 300B amp, or a direct-coupled 2A3 amp. The 2A3 option was included specifically to continue the Afterglow/Paraglow design history. There were several variants over the years.

Direct coupled power amps like this sound great when properly adjusted. But they are pretty high-maintenance because the stages are so interconnected, and the start-up transient causes some problems with a few tubes - most old stock seemed to handle it, as did the Sovtek we supplied. The last revision of the Paramount addressed the problem (and a few others). The Paramount is also discontinued now, and we no longer have any direct-coupled 2A3 designs.

I can go into more of the history, but it would be better on the Bottlehead forum. This forum has rules to prevent using it as an advertising platform and I fully agree these rules are important and valuable.

 

RE: Yes, they are cathode biased, posted on January 30, 2017 at 18:07:02
audiophilewannabe
Audiophile

Posts: 503
Location: toronto
Joined: July 19, 2004
I'll go to BottleHead forum. Since I'm already here I'll continue on. The driver tubes are 5965..does that make sense?? According to the fellow I got it from the Kit was assembled by "Tube Guru", I don't really know who they are, I suppose he is saying that it was professionally put together. Because its a direct coupled, they installed a standby switch, works like a mute..I really like what I hear so far. I'm currently using a Yamamoto A08S and they are very close, I'm actually leaning towards the 2A3. That being said I need to hear them more.

 

RE: Yes, they are cathode biased, posted on January 30, 2017 at 20:19:54
RPMac
Audiophile

Posts: 275
Location: So. Mississippi
Joined: January 3, 2005
The 5965 was used in the original Paraglow kit.
They would need to know that to help you at BottleHead.

The EXO-36 are 16 ohm secondary
The EXO-35 are 8 ohm

 

Opps and thanks , posted on January 31, 2017 at 01:49:42
Frihed89
Audiophile

Posts: 15121
Location: Copenhagen
Joined: March 21, 2005
so, no cathode resistor?

 

RE: Opps and thanks , posted on January 31, 2017 at 08:37:27
Tre'
Industry Professional

Posts: 12022
Location: So. Cal.
Joined: February 9, 2002
I believe there is a cathode resistor and a large value one at that.

The current through the output tube creates more voltage at the cathode than there is at the grid.

The grid is connected to the plate of the driver tube so, in the end, it's a combination of the driver tube's plate voltage and the voltage created by the output tube's current flowing through its cathode resistor that "biases" the output tube.

Tre'

Have Fun and Enjoy the Music
"Still Working the Problem"

 

Exactly! thanks (nt), posted on January 31, 2017 at 13:57:11
Paul Joppa
Industry Professional

Posts: 6676
Location: Seattle, WA
Joined: April 23, 2001
nt

 

Does it have a name? nt, posted on February 1, 2017 at 09:18:52
Frihed89
Audiophile

Posts: 15121
Location: Copenhagen
Joined: March 21, 2005
nt

 

RE: Updated Paraglow 2a3 SET, posted on February 11, 2017 at 07:01:35
Mr_Steady
Audiophile

Posts: 904
Location: North Florida
Joined: August 19, 2014
Hi Paul,

I have an idea you don't want to hear.

It would be cool if BH resurrected the Paraglow with updates, like an adjustable resistor and meter for biasing the driver tube of the type that you discussed on this forum a year or two ago. You already have the slow start module. More coolness if the builder could select series or parallel feed OPTs. AC on the filaments please.

I notice on the new BH 300B amps recently released the type of filament current is builder selectable, and you added a pair of linear gain controls for help in bi-amping. Both are very nice features. Congrats.

Just for fun. I couldn't resist! :)

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Big speakers and little amps blew my mind!

 

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