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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,
Edits: 01/29/17Follow Ups:
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.
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! :)
Big speakers and little amps blew my mind!
Yes, came with all magnequest iron
Replaced by Paramount
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.
At least, not in the normal meaning of the phrase. They are direct coupled.
so, no cathode resistor?
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.
Have Fun and Enjoy the Music
"Still Working the Problem"
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.
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!
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.
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
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