Bottlehead Forum
Bottlehead Kits => Legacy Kit Products => Topic started by: Doc B. on June 16, 2013, 03:45:10 PM
-
Sorry this took so long, folks. We had the manual complete, but got caught up with a long wait for iron-
http://www.bottlehead.com/store.php/products/iron-upgrade-kit-for-sex-kit-20 (http://www.bottlehead.com/store.php/products/iron-upgrade-kit-for-sex-kit-20)
-
I know people will be curious if this upgrade is compatible with the impedance switching kit. Unfortunately it is not, due to wiring differences between the S.E.X. 2.0 and 2.1.
-
With a little ingenuity, these could work quite nicely in the old Paramour I/II if you have the Speco output transformers (in my opinion at least).
-PB
-
Aaarrggghhhh. You would do this today. I was about to buy the Crack and now this. Now I have to make a decision.
-
And you forced me to make a decision. If you check your pending orders you'll see I got the Crack w/ Speedball Update.
New iron has to wait.
Blast you Bottleheads and your cool stuff.
-
Thanks John!
-
PB -- great minds think alike :-) I bought one set of this iron for my s.e.x. 2.0 but another will be on the way in the future -- to pair with my second pair of pt2s. Now I just have to find some plate chokes for a 300b amp and I could have a set of monoblocks for 45s, 2a3 and 300b.
-- Jim
-
With a little ingenuity, these could work quite nicely in the old Paramour I/II if you have the Speco output transformers (in my opinion at least).
-PB
I'm very interested. I know this iron is the same as in the Stereomour's so I had the same idea. I don
-
With a little ingenuity, these could work quite nicely in the old Paramour I/II if you have the Speco output transformers (in my opinion at least).
-PB
I'm very interested. I know this iron is the same as in the Stereomour's so I had the same idea. I don
-
1. Is it safe to assume that a Paramour II could use this iron in the 45 configuration?
Yes, use the plate choke connections advised in the SEX upgrade instructions that come with the kit for the 45.
2. Would it be advantageous to reuse the Triad CX7 choke in the power supply like in the original Paramour II iron upgrade? (CRC to CLC)
Absolutely a great idea.
3. Would the parafeed cap value need to change?
I don't even remember what the original value was, lol, but I think you could try anything in the neighborhood of 1uF to 4.7uF.
4. Would the cathode resistor need to be optimized for the new iron?
I don't believe so, as the original Paramour used 4K output transformers.
5. This one might sound a little stupid but... The kit includes two output transformers and two plate chokes, right? I assume that the picture is only showing one channel.
Yes, the price is for a pair of iron.
To ratio the output transformers to 4K, just adjust the secondaries (run your 8 Ohm speakers on the 16 Ohm configuration). The impedance switching kit could make the experimentation pretty fun.
-PB
-
Thanks PB. I ordered up a set last night. BTW, the original value for the parafeed cap was 3.3uF 630v. The Paramour upgrade kit with the BH5/BH6 MQ iron changed the value to 10uF.
-
For the 45 the choke will use the 40 henry/35mA taps, so the nominal cap is 5uF. It was higher with the old MQ iron because that was a lower 3K impedance transformer.
Aside #1 - you would calculate a 1.25uF for the 10-H choke of the original, but that gives a rolloff around 45Hz, so I spec'd 3.3uF back then to extend the bass, at the price of less deep bass headroom - ending up with 3.3uF.
Aside #2 - In the Stereomour 2A3 using the 20H/50mA taps, the calculated values is 2.5uF, so we still ship 3.3uF as being close enough for either 2A3 or 45.
-
For the 45 the choke will use the 40 henry/35mA taps, so the nominal cap is 5uF.
Argh, I wish I knew that before I placed my [wrong] cap order.
-
As always a range form half to twice the nominal are all pretty good. That's 2.5 to 10uF. With the new choke, the differences are i the 12Hz range - not a big problem area!
-
Can someone tell me if the new iron uses #6 or #8 hardware? Also what is a good source for fiber shoulder washers and solder tabs? -Thanks.
-
#6. Because we're nice people, we will be including fresh fiber washers, since a lot of them will be crushed after sitting under pressure for years on the upgrade amp. We can toss anything else you might need into your box. Email your requests to replacementparts <at> bottlehead <dot> com and I'll make sure you are set.
-
The iron should have #6 hardware. For an extra dollar or two, you could undoubtedly talk Eileen into sending you some fiber washers and solder tabs.
-PB
-
Any estimates as to when these transformers will be ready for shipping?
-
Early next week barring unforeseen delays.
-
Early next week barring unforeseen delays.
Awesome, thanks.
-
So, it is looking that one will still have to configure the new iron as an autoformer -- is this a correct assumption? If so, I'm also guessing that balanced mode would not be possible with that configuration.
-- Jim
-
That is correct, it remains an autoformer configuration.
-
Will the instructions be posted online or something? My kit didn't come with any.
-
There is indeed a manual for the kit. If you PM me your e-mail address, I'll send you a link so you can download it.
-PB
-
Paul,
I got the manual, thanks. I have a couple more questions if you don
-
Yes, blue and red for the #45, with heatshrink over the black wire.
As far as the impedance goes, you will want to use the OT-2 transformer, but not quite as-wired in the SEX. The SEX amp uses the transformer to provide an ~8K reflected load to the plate of the output triode, while the Paramour wants to see 4K.
Consequently, for something like an 8 Ohm Orca, you can wire the OT-3 transformer for 16 Ohms to reflect the correct load.
-PB
-
Yes, blue and red for the #45, with heatshrink over the black wire.
As far as the impedance goes, you will want to use the OT-2 transformer, but not quite as-wired in the SEX. The SEX amp uses the transformer to provide an ~8K reflected load to the plate of the output triode, while the Paramour wants to see 4K.
Consequently, for something like an 8 Ohm Orca, you can wire the OT-3 transformer for 16 Ohms to reflect the correct load.
-PB
Got it, thanks!
-
Along the same lines as Tom's questions -- can the opt be configured for 4k primary and 16 ohm secondary?
Thanks,
Jim
-
Yes.
-PB
-
Ok, now on to the plate chokes... will these new plate chokes work as ps chokes in the paramour -- 2a3 or 45, and would they be an upgrade over the triad c7x? Gears are turning.
-- Jim
-
Ok, now on to the plate chokes... will these new plate chokes work as ps chokes in the paramour -- 2a3 or 45, and would they be an upgrade over the triad c7x? Gears are turning.
-- Jim
The C7-X has 10H of inductance, the upgrade iron has 20 or 40H, depending on the tap used, so I would use the C7-X for power supply duty.
-PB
-
The plate chokes are 2 or 3 times the resistance of the C7-X, so they drop more voltage. And they are designed to handle the output tube plate current. Of course they handle some AC current as well, so they can handle a bit more DC as long as the AC is small (i.e. not in a choke-input filter). At first glance the temperature rise looks OK.
-
Thanks, Paul, just an idea and I really didn't know the Rdc specs for the various chokes except the c7x, which every bottlehead probably knows is 270 ohms ;-).
Another opt question: is there a way to configure the opt for an 8 ohm load with a primary closer to 5k, instead of 4 or 8? I knew there are some intermediate taps in there somewhere but no idea what they are. I'm seriously thinking of putting this opt in the sr-45 as the nickel with the 45 tube seems to be just a bit too sweet.
-- Jim
-
You can get 5K:16 (roughly) but nothing else.
-
Thanks Paul, but after thinking about it a bit I decided that I really didn't want to back myself into the 16 ohm speaker category.
-- Jim