Any tube amp guru help identify components in circuit.

[kelossus]

Hi Guys

 

I am wanting to upgrade the coupling capacitors in tube amplifier as well as the driver electrolytics.

 

From the pictures are you able to help me determine what these components are so I can order the parts and get them replaced? I think I know which ones they are but want to make certain. The amp is an Primaluna HP Integrated.

 

 

 

 

[VanArn]

The white coloured 'DoRoch' capacitors appear to be used as coupling and bypass capacitors in the amplifier. According to the Stereophile review they are polypropylene types. 

Edited September 19, 2017 by VanArn

[kelossus]

Are the white film caps attached to the driver and gain tube pins crucial coupling capacitors as well?

Edited September 19, 2017 by kelossus

[VanArn]

 You need to have a circuit schematic or a knowledge of valve circuits to help indentify the exact  components  and whether they are critical to obtaining the best performance. Anode to grid capacitors require very low levels of leakage and  dielectric absorption and polypropylene capacitors are already the better performers, especially  of film and foil construction and of  the highest available voltage rating. The crucial  component in designing a valve amplifier is the output transformer , this is followed by the actual cct. design and  the  layout.

[kelossus]

Yeah I have no knowledge of the kind hence this thread. I was just hoping someone would be able to help determine these things.

[Guest Muon N']

All I can do from a pic (there be a lot in there for a tube amp) is that the 2 groups of 4x film caps are inter-stage coupling, at the front 2 of the 4 other white film caps would likely be input blocking caps maybe, and yes, those ones at the end of the big PS caps are by-passes.

 

Sorry I can't help more from the pics.

 

I'm not a Guru by a long stretch, maybe pre apprentice or work experience guy

 

Edit: need a schematic, so take my post with a pinch of salt.

Edited September 19, 2017 by Muon N'
Typo

[kelossus]

2 minutes ago, Noum said:

All I can do from a pic (there be a lot in there for a tube amp) is that the 2 groups of 4x film caps are inter-stage coupling, at the front 2 of the 4 other white film caps would likely be input blocking caps maybe, and yes, those ones at the end of the big PS caps are by-passes.

 

Sorry I can't help more from the pics.

 

Thanks! Thats great info.

Do you know if the inter-stage coupling capacitors have the most effect on the sound?

 

@Zaphod Beeblebrox How is your tube knowledge as good as your SS?

[Guest Muon N']

This is just my personal view, and as is known some don't even think cap changes make any difference.

 

Anyway, things i prioritise in possibly upgrading as far as quality goes (can call it different sounding) are the coupling caps, input caps, cathode resistors and cathode by-pass caps if they are there.

 

Definitely need the schematic to confirm things and know whats what for sure.

Edited September 19, 2017 by Muon N'
typo, i need a proof reader

[Guest Muon N']

If those 22uF 450v electro's are indeed feeding the input stage, maybe if they fit, Solen PB caps work well in this position in amps i have seen done with them, use them myself in those positions.

 

Again, I'm part guessing what is what from the pics, so keep that in mind

[kelossus]

The 22uf electro's are in the driver stage.

[Guest Muon N']

Same, but need to know what they are doing there before doing anything.

 

And if indeed PS caps the Solen PB is suitable, but not suitable for signal paths or not sound wise anyway.

 

Edit: Someone like @rawl99 could be better at looking at this Premaluna thing

Edited September 19, 2017 by Muon N'

[Zaphod Beeblebrox]

1 hour ago, kelossus said:

 

Thanks! Thats great info.

Do you know if the inter-stage coupling capacitors have the most effect on the sound?

 

@Zaphod Beeblebrox How is your tube knowledge as good as your SS?

 

Van's comments are pretty much on the money. The emphasis being that the output transformers are, by a very considerable margin, the most important single components in a valve amp. This is why Earle's amps sound so good and many cheap, Chinese amps don't. 

[Guest Muon N']

*sigh*

 

I respect you ZB and your knowledge but this Chinese amp bashing is like a broken record.

 

Yeah, I disagree with a fixed statement like that, I do agree the OPT's are very important to the sound possibly the most single important thing, but to disregard everything else that influences the sound is something I do not agree with.

 

But I'm small fry so I'll leave it there

Edit:  forgot to mention that the OP has an amp and is not asking for recommendations, so....I don't understand the post. I also think Earle's amps are nice amps with fine transformers, and good value, but when It's often accompanied with the putting down of other amps, I don't see it as needed, Earle's amps can sell themselves, and Earle offers 5 star service.

 

Edited September 19, 2017 by Muon N'

[Ancientflatulence]

You are in Queensland ........ if you are in the South East Take it to or at least ring Mike Lenehan ............ he mods Prima Lunas

 

Edited September 19, 2017 by Ancientflatulence

[kelossus]

6 minutes ago, Ancientflatulence said:

You are in Queensland ........ if you are in the South East Take it to or at least ring Mike Lenehan ............ he mods Prima Lunas

 

 

Mate you are an absolute legend! Do you have an higher resolution of that photo?

[Ancientflatulence]

I am sorry that is a pic of my amp that Mike sent me taken with his phone after he did the mods on mine .......... I can't even tell you what the caps are ....... sorry .........

[kelossus]

I can see they are Jensen Electrolytics and Jupiter Wax caps.

[MattyW]

I need to pop over for a listening session once you've finished modding this Chris

Sent from my Pixel using Tapatalk

[skies2clear]

I would safely say the 8 x 0.22uF film caps are signal coupling caps from driver to output tube inputs. Make sure these are 600v rated minimum.

The 4 electro 22uF are probably power supply local decoupling for B+ for input or driver stages.

The other 4 film caps are very likely coupling caps in the earlier stages.

 

Having the amp in my hands of course would completely verify all this, but when it comes to tube amps, usually not much new under the sun. 

 

If the white film caps are Chinese made, then upgrading them to better (Mundorf) or whatever floats your boat would be worthwhile. Not sure how much you'd gain by replacing the 4 blue electrolytics....only one way to find out.

 

Youre welcome to PM anytime.

[kelossus]

11 hours ago, skies2clear said:

I would safely say the 8 x 0.22uF film caps are signal coupling caps from driver to output tube inputs. Make sure these are 600v rated minimum.

The 4 electro 22uF are probably power supply local decoupling for B+ for input or driver stages.

The other 4 film caps are very likely coupling caps in the earlier stages.

 

Having the amp in my hands of course would completely verify all this, but when it comes to tube amps, usually not much new under the sun. 

 

If the white film caps are Chinese made, then upgrading them to better (Mundorf) or whatever floats your boat would be worthwhile. Not sure how much you'd gain by replacing the 4 blue electrolytics....only one way to find out.

 

Youre welcome to PM anytime.

 

Are the signal coupling capacitors the most influential to overall sound of the amp? Should I get the best caps I can afford for these?

 

The other film caps on the small tubes are they less important? The 22uf's must have had an impact on the sound if Lenehan only decided to change the 8 signal coupling capacitors and the 4 electros. I believe now he replaces all the white caps as well the 4 electros.

[MattyW]

I imagine it would depend on the sonic signature you enjoy.  Dueland caps are nice.... Though their speaker cables have a similar sonic signature also

 

As I understand Jupiter's are very nice also. I've a combination of French Solen Tinfoils and Russian KY40-9 PIO's. The Dueland speaker cables were what really brought my system to life though

 

Paul at Falls Audio on the Gold Coast will install them so you can audition the caps. Keep changing the caps till you get the sound you want. I highly recommend him.

Edited September 21, 2017 by MattyW

[RoHo]

4 minutes ago, kelossus said:

 

Are the signal coupling capacitors the most influential to overall sound of the amp? Should I get the best caps I can afford for these?

 

The other film caps on the small tubes are they less important? The 22uf's must have had an impact on the sound if Lenehan only decided to change the 8 signal coupling capacitors and the 4 electros. I believe now he replaces all the white caps as well the 4 electros.

The signal coupling caps are one of the most influential components, all else being equal.  How to define the "best" capacitor is, however, extremely problematic.  You can spend hundreds of dollars on a silve foil/ teflon etc capacitor or comparatively little on a still good-quality cap like an Obbligato or Mundorf Zn.  Does the super-duper one sound 20 times better?  How can you judge such things?

I still struggle to have a definitive answer.  What I do know is that the coupling caps are only one of many components in your amp. There's only so much improvement possible by upgrading this one component.  And so how much is it worth spending on this one component?

The 22uF electolytic caps might be the cathode-bypass on the input stage.  That's also quite an influential position.  The standard ones appear to be Nichicon which are good industrial types.  I don't know much about the Jensen's Mike has replaced them with but they are still electrolytic types.

[kelossus]

20 minutes ago, MattyW said:

I imagine it would depend on the sonic signature you enjoy.  Dueland caps are nice.... Though their speaker cables have a similar sonic signature also

 

As I understand Jupiter's are very nice also. I've a combination of French Solen Tinfoils and Russian KY40-9 PIO's. The Dueland speaker cables were what really brought my system to life though

 

Paul at Falls Audio on the Gold Coast will install them so you can audition the caps. Keep changing the caps till you get the sound you want. I highly recommend him.

Duelunds, would love to use them but they are too expensive. I am still wanting a pair of Duelund speaker cables, did you buy yours from Geoff?

 

I think the Jupiter's tread the middle ground as not too expensive and not overly budget, same as the top tier Mundorf caps.

 

Definitely keeping Paul in mind if Nigel isn't willing to do the upgrade.

[kelossus]

5 minutes ago, RoHo said:

The signal coupling caps are one of the most influential components, all else being equal.  How to define the "best" capacitor is, however, extremely problematic.  You can spend hundreds of dollars on a silve foil/ teflon etc capacitor or comparatively little on a still good-quality cap like an Obbligato or Mundorf Zn.  Does the super-duper one sound 20 times better?  How can you judge such things?

I still struggle to have a definitive answer.  What I do know is that the coupling caps are only one of many components in your amp. There's only so much improvement possible by upgrading this one component.  And so how much is it worth spending on this one component?

The 22uF electolytic caps might be the cathode-bypass on the input stage.  That's also quite an influential position.  The standard ones appear to be Nichicon which are good industrial types.  I don't know much about the Jensen's Mike has replaced them with but they are still electrolytic types.

Thanks mate, leaning towards the Jupiters as Lenehan must have been impressed and he has Duelunds on tap. I noticed Dallas Clarke also changed some Electrolytics in a Conrad Johnson preamp I use to have to the Jensen Electro's.

 

Might have a browse at the ZN's and see their costing also.

[MattyW]

Yes,  I got the 2m braided cables from Geoff at Aurealis.  @Noum  loaned me his UPOC cables though upon his reports of the Dueland I borrowed a pair from Geoff.  Took me just a few minutes to decide that there's no way they were coming out of my system. To me it added what I liked about using a Tokos Cosmos volume pot in my last amp,  though without the channel imbalance. Without it the system did sound great though left me wanting more. A very worthwhile upgrade.