Primaluna Prologue 2 Working on one channel

[Fran]

It was actually the screen (aka grid) resistors on the KT88s that were gone. Typically these resistors are there to limit screen current which in turn prevents the valve burning itself out (kinda like a crude fuse). Why would such a thing happen? Well, first one I can think of offhand would be applying a signal to the input while having no speakers connected. Another one, not common in hifi amps but very common in guitar amps, is when an amp might be overdriven.

From what Tony has told me, this is very likely to have happened before the amp got to him, and I'd say the resistors had got a roasting or 2 before, this normally causes the resistance to increase, which would in turn limit power severely to the point where you would hear distortion at low levels - which were exactly the symptoms here.

Anyway, all 4 are replaced now with new ones and all should rest well in primalunatonyland. This is a very nicely neatly assembled amp BTW, looks well built under the hood. Not surprised that they have a good rep, and great longevity. I look forward to hearing it in my own system until the owner collects :)

BTW Tony, I have a set of EL34 and KT66, and maybe 6CA7 too which should just plug into this amp - when you come to collect we can try some if you like.

Fran

[Adrian]

Forget about the "The Fonzie Touch".... this is "the Franzie Touch"

Well done to all... good to hear a success story!!

[tony]

Thanks for the clarification Fran. Yes will definitely try out the 34's when picking up.
The prima luna is nice and compact for a valve amp a bit like the cyrus shoebox.Not as deep as the cyrus but probably a bit wider. The amp is very neatly done inside it but it is built to a price while it looks fine amps like
Fergus's synthesis shine have a much better finish(chrome etc). Certainly for anybody looking to dip their toe into valveland it offers a lot of versatility (takes multiple valves.autobiasing, 40watts per channel, hand wired, dutch design/chinese build)

They come up for sale fairly often on wigwam and pfm and along with the puresound a30( I think) are well worth checking out.

[tony]

Returned to the repair shop today to collect.Excellent service and a bit of listening to confirm all is well. Have to say again the finish and quality of Fran and Gerry's speakers is hugely impressive. Really professional job. Very modern looking and even though they are tallish floor standers they are fairly shallow in depth and to my mind certainly wife friendly. Sound sublime playing oscar petersons we get requests. Better with Frans Dynaco/pre than my primaluna but importantly for me the amp is working perfect.

Just a final many thanks Fran for getting the show on the road again and coming to my rescue much appreciated.

[jaybee]

Thanks for the clarification Fran. Yes will definitely try out the 34's when picking up.
The prima luna is nice and compact for a valve amp a bit like the cyrus shoebox.Not as deep as the cyrus but probably a bit wider. The amp is very neatly done inside it but it is built to a price while it looks fine amps like
Fergus's synthesis shine have a much better finish(chrome etc). Certainly for anybody looking to dip their toe into valveland it offers a lot of versatility (takes multiple valves.autobiasing, 40watts per channel, hand wired, dutch design/chinese build)

They come up for sale fairly often on wigwam and pfm and along with the puresound a30( I think) are well worth checking out.

Is the KT88 EL34 swap the only difference between the one and the two?

Im starting to gravitate toward one....

[tony]

Is the KT88 EL34 swap the only difference between the one and the two?

Im starting to gravitate toward one....

I have been told that the One could also take Kt88's but to be on the safe side I wouldnt risk it. The 2 takes 34/88/90's and 6550's and their equivalents KT66 etc etc.

Can't remember what they are but there are some improvements to the parts in the amp also. There is no remote with these amps just in case that is an issue for you.

I think an orchestra reference would be needed to best it I think and that would be more expensive and very hard to find.

I think for anybody looking for an entry level valve amp and doesnt want to be manually biasing and would like to try out tubes it is ideal. Especially secondhand. I think new Noel Cloney sells them for circa €1800. And Noel recommends them also for use with 57's

[Diapason]

Jaybee, there's a lovely little Icon Audio in the shop that might appeal to you.

[jaybee]

the blackrock shop?

[jaybee]

they were on my list alright, there was a stereo 40 mkii on' t bay that went for ~€600, he wouldn't deliver though.....

[Diapason]

Yes, in cloney. It sounded lovely with the System Audios in the front room. Worth a visit perhaps!