Which do you prefer, KT88 or 6550, and which brand?

[Psilonaught]

It sounds like rectifiers where the sound isn't being created by the tube but by the changes in voltage / load etc? Maybe that is the reason for the audible difference between these types of signal tube?

 

[mac72]

Depending on the circuit used by designer signal tubes and their working point are chosen for a certain reason ie max. voltage swing , linearity and so on . If you use tube with different parameters it possibly would change working point , cut off conditions , how it loads next stage so yes it most likely would be sounding different but mostly because is not working as intended by the designer. 
There are many very close substitute tubes for Ecc82 , if anything I would stick to long life military versions as these hold their parameters for long time , some up to 10k hours which is quite important if you were to buy some old stock tubes as there is not many real NOS tubes left .

 

[pmcuk]

Audio Emotion, the UK melody dealer, is contacting the company owner and trying to find out if the units are KT120 compatible (a US dealer told me not, but he was v rude and isn't the manufacturer, so getting a second opinion!).

I'll try and find out about the signal tube heater voltage. I've been told to try 12BH7 if the higher heater voltage is supported.

It's not the heater voltage with E80CC, it's the heater current. Voltage is the same as 12A*7 types - 12.6 on pins 4 and 5 or 6.3 if you use the centre tap on pin 9. The 12AU7 is 300mA current, the E80CC is 600mA. If the extra current is OK, you can always change the cathode resistor for a better operating point. 12BH7 is also 600mA heaters. Don't substitute that without advice on the heater supply. Using 2 might be safe enough (?), but as I said, 4 adds 1.2A current. 

But anyway, since all the feedback suggests the Gold Lion B749 is the one, I'd go for that. 

 

[Psilonaught]

https://www.thetubestore.com/genalex-gold-lion-ecc82-b749 if you can find them the B749 are reputed to be best of all, bit of a legend. 

So are these 300ma? These do seem to get good reviews so might buy a set to compare to the NOS RCA.

As an aside, I'm so thrilled with the sound eminating from my speakers thanks to the Melodies. I prided myself of having neutral and natural sounding system, but swapping out the already outstanding Plinius just takes the neutrality up a notch. There isn't a hint of artificial glare anywhere, it is so non-fatiguing.

That's with dirty cheap signal tubes. 

One happy camper here  :stereo:

 

[pmcuk]

With a valve amp it makes a preamp a lot easier. No need for a very low output impedance. 

Are these new amps balanced in or single ended? Do you place them next to the speakers, or in a rack beside all the other units with a long cable to the speakers?  

 

[Psilonaught]

With a valve amp it makes a preamp a lot easier. No need for a very low output impedance. 

Are these new amps balanced in or single ended? Do you place them next to the speakers, or in a rack beside all the other units with a long cable to the speakers?  

These have balanced inputs and I sit them on the rack, using 5m cables.

I could swap these over with my Emotiva  monoblocks that power my bass panels, which currently sit next to my speakers, but given they are relatively fragile, I'd prefer them to stay on the rack. My kids use my listening room for various Nintendo Switch dance games...

 

[falcoron]

I’ve had a few valve amps with kt88 and 6550 and in everyone I preferred the 88 tubes, I found the 6550 a bit dull  in comparison.( others my find differently) 

I tried most of the so called fancy tubes and always came back to Electro Harmonix they never let me down very reliable and super  quality. That sounded great. 

Over the years I bought  6 sets of PSvane  in various types from std to black to silver coated etc etc most were either noisy  or failed. I gave up on them as cheap tubes well packaged for audiofools like me. 

JJ and Sovtec were hit and miss too. 
 

was told ( not sure if true ) the Genelex are identical to EH 

I had a set of them and they sounded great but didn’t keep the amp long enough to see how reliable they were, doing comparison from EH and Genekex gold lion I could here no difference whatsoever.

only my subjective findings of course. 
what I did find in every valve amp I owned was I got better results rolling the small tubes that I ever did rolling the large ones.  

 

[egg1dog]

I was looking at these very amps !

How do they compare to the Plinius class A?

I have the SA103 and the grip this has with the woofers is very impressive, can a valve power amp do the same?

 

[Psilonaught]

I have the SA103 and the grip this has with the woofers is very impressive, can a valve power amp do the same?

Probably not. I use mine above 140hz.

I use Emotiva HC-1 monoblocks for the x4 bass panels in my Magnepans. 600w each and extremely high current delivery 

In terms of comparison, i'm using the stock tubes (better ones on order), so I will provide proper feedback at that point, but suffice to say, I am selling the Plinius at some point. It is fabulous but I don't need that much power thanks for the active crossover and the KT88 is more natural sounding.

 

[MF 1000]

I use 750 watt bridged mono solid state bass guitar pa amps to drive my 18” driver  bass section 

 

[antonio66]

"I tried most of the so called fancy tubes and always came back to Electro Harmonix they never let me down very reliable and super  quality"

I'm new to tube amps, but have one now in a second system. I have listened to many dems on YouTube (I know you can never really tell the quality, but it was the only way for me to get some sort of idea) and always like Electro Harmonic, the other one being GE. I've purchased a few pre amp valves to try, but since I'm out of the country and my purchases go to my uk address I have not been able to try them yet. This short review finally made me press the button on a couple of GE 6189/12AU7's   Quickies: Minimum Reviews for Maximum Audiophiles - Positive Feedback (positive-feedback.com)

 

[Psilonaught]

Because I am weak I decided to splash out on x8 Shuguang kt88-Z treasurers. 

 

[gav]

Hi I have these Mono blocks is Australia , can you tell what Fuses you have in your ones. and in Australia they are known as  Melody M88Q

What I know is mine are 5 Amp 250volt  but there is no indication on the fuse as to are they Slow or Fast blow

 

[gav]

Just add an older shot of mine /april 2020

 

[Psilonaught]

Just add an older shot of mine /april 2020

Hi

It says F-5A on the rear no?

Obviously that's a fast blow 5 amp fuse.

 

[gav]

Oh wow I totally missed that, it is difficult for me to get to the back , eventually I shall reconfigure  my equipment racks  for better access to all gear.

Thank you 

 

[antonio66]

Because I am weak I decided to splash out on x8 Shuguang kt88-Z treasurers. 

How are you getting on with these?  They were on my shortlist, but I went for Sovtek 6650WE's which I got at a great price in the Black Friday sale.  Unfortunately due to an amp fault, on of the tubes glowing bright red, I have been unable to hear them except for about 10 seconds to which I thought they sounded good.  They are replacing 'cheap' Chinese KT88's which I believe are Shuguang basics.

 

[Psilonaught]

How are you getting on with these?  They were on my shortlist, but I went for Sovtek 6650WE's which I got at a great price in the Black Friday sale.  Unfortunately due to an amp fault, on of the tubes glowing bright red, I have been unable to hear them except for about 10 seconds to which I thought they sounded good.  They are replacing 'cheap' Chinese KT88's which I believe are Shuguang basics.

Still going strong, and despite what other people say, I bought these from AliExpress from a reputable dealer, and they didn't immediately blow up...I think I paid £450 for the x8.

 

[antonio66]

HiFi Part Store?

 

[Psilonaught]

HiFi Part Store?

JEMOSA

Always sends me a photo of the factory test numbers to show they are matched.