45s in steromour II ?

[lordvader]

Hey all.

So I really want to build a 45 amp, and was wondering if the Stereomour II (or possibly the Kaiju) can be converted to use 45 tubes ? I know the previous version did, but have yet to read anything about such a mod for these amplifiers.

Thanks !

[Natural Sound]

It is interesting that there is no mention of running the Stereomour II with 45 tubes. I'm sure it can. The main differences between the I and II are the universal power transformer and a second 12AT7 to add two triode sections that will be used in future upgrades. But lets wait for someone at Bottlehead HQ to give the official answer.

[Brent]

http://bottlehead.com/smf/index.php?topic=7804.msg75442#msg75442

PB's answer to this question from the launch/intro thread. SPOILER: the answer is yes. 

[Natural Sound]

Thanks Brent!

[Paul Joppa]

We have not yet generated a description for how to make the change, but we did allow for the possibility in the design phase. We decided to leave it out of the manual because relatively few make the change, and it just adds confusion for the many who don't.

[Natural Sound]

We have not yet generated a description for how to make the change, but we did allow for the possibility in the design phase. We decided to leave it out of the manual because relatively few make the change, and it just adds confusion for the many who don't.

Makes sense, Paul. Will the conversion instructions be made available on the forum via a "sticky" or something? I haven't pulled the trigger on a Stereomour II yet. I'm waiting a little to see what you guys have in mind for the upgrade goodies. Chances are good that I'll be trying the amp in both configurations since I have a nice stash of 2A3 and 45 tubes.

[lordvader]

Thanks for the update !

What about the Kaiju (didn't want to ask the same question twice, btw) ?

[Paul Birkeland]

The Kaiju will not have a 2A3 or 45 option.

[Doc B.]

Just to clarify the Kaiju 300B amp is, in single ended tube terms, a high power amp. The Stereomour II is a lower powered SE tube amp, and a 45 wants to live in a Stereomour II. There is not really any point in putting an Aprilia RSV4 engine in an Alfa Romeo 4C. It will work a lot better in an Aprilia.

[kevner21]

to give some incentive to the designers I wont buy a stereomour 2 until you can convert it to #45 tubes, lol from the time PJ found the error in the 45 conversion in another topic , I have just been thrilled with my stereomour 45

[Paul Joppa]

The ability to convert to 45s is built into the design, we just haven't written instructions yet. It is as simple as the original - swapping out a few resistors and exchanging a couple plate choke wires. We left out the instructions in the main manual to reduce confusion.

[kevner21]

no , I'm in no hurry  to get the stereomur 2 , I'm just in disbelief that 1.75wpc is making such wonderful sound after 40 of spending thousands of dollars foolishly to get nothing even close to this. which has been around in radios 70, 80 years. cant get over it, and again  thank you, thank you, thank you!!!!!!!!!!!!!!!!!

[mkane]

  Just made the change myself. Bliss

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fi285.photobucket.com%2Falbums%2Fll58%2FMKane63t%2FDSC_0487%25203_zpsszea8wc4.jpg&hash=cad7dd193819f3b7bb5ae4258e8f277d2dd14431)

[lordvader]

So what do I need to do to get this working ?
My Stereomour II should be arriving any day now

[rockdoc]

So what do I need to do to get this working ?
My Stereomour II should be arriving any day now

I'm really curious about this too. I  really prefer 45s, and am looking forward to building one of these. Would this mod use the same output transformers as for the 2a3?  What is the impedance on the OTs in the kit?

rockdoc