eros hum and sound quality

[Paul Joppa]

I can't locate any data on a 5775.

[Doc B.]

It's a bigass, obscure rectifier. Hence I am pretty sure he means 5755. Kinda like a 12AT7.

[mkontor]

Yes I think I remember the number wrong, only came up briefly on a conversation about EF86

[Grainger49]

Take a look in the Eros Phono file.  I have a thread listing the drop in replacements/equivalents for the two audio tubes in the Eros.  My particular favorite are the USSR Military surplus tubes.  They are more rugged than other designs.  That is for both the EF86 and the 6922. 

They also tend to be quieter as well.  The ones from the 60s and 70s are reported to be the best.  Most of the sellers will send you what you ask for.

[mkontor]

Just to keep you updated, the Eros got lost on the way to my tech friend, hence the delay; it's on the way back to me and then I have to send it to him again, so I won't have anything to report until late next week.

[Grainger49]

I would suggest that you send it to Bottlehead instead.  They know the circuitry, have tape decks to test with therefore they can be more efficient locating your problem.

[Doc B.]

There seems to be a bit of this going around. I got call from a tech in Texas yesterday (Pete Nyquist, super nice gent!) who had been sent a deck we modded a couple of years ago. He told the client it should have gone to us because we designed the mods done, and when he called me and I concurred he already had it packed and just wanted our address.

I'll just suggest that perhaps the return of the shipment is a sign from the cosmos...

[mkontor]

Hi Dan
I've got the unit back now and thought I would check it out again before sending it to my tech and found that in the process I have lost the instruction manual which I had copied to my laptop, which I had to restore, so lost the file. I also lost the CD!!!!!
Can you please send me the PDF? I have dropbox ([email protected]) or please burn an image and point me to it? It will take too long if you post me a new CD.

Meanwhile I measured the resistor in the EQ section and they are both 200K, from memory that's correct. Did some other measurements too, all OK (from memory and more to the point, equal in both channels).

The hum is still there, fairly low level, but my tech is an expert at making tube amps with no hum at all.

I hooked up my LP player again as my Pioneer is wired up as stock again and it's a pain to re-wire, and the sound is definitely too warm, lacking in bite and treble. It's much brighter, has more attack thru the phono stage, so there is something amiss...

Without the instructions or at least a circuit my tech will not be able to do much...

Cheers,
Mike

[mkontor]

Dan
I am going to send this to you. It's easier. You know this model.
Cheers,
Mike

[Doc B.]

I promise we will give it a full exam and make sure it functions to exact spec.

[mkontor]

I don't doubt that one bit!
Additional to my note in the box, I think it might be wise to fit a 110v transformer as the one that's in there runs very hot, and I can use a step down transformer, not a bad thing as it provides some  filtering.

[mkontor]

Could you please somehow send me the instructions as I do seem too have lost this...

[Paul Joppa]

...
Additional to my note in the box, I think it might be wise to fit a 110v transformer as the one that's in there runs very hot, and I can use a step down transformer, not a bad thing as it provides some  filtering.

The transformer voltage has no effect on the heat; the lower voltage transformer takes twice the current so it makes the same heat.

And yes, the Eros transformer does run fairly hot. That's because it has a lot of turns, to minimize the stray magnetic field and any mechanical vibration or buzzing.

[mkontor]

Well actually I knew that, somewhere in the back of my mind....

[mkontor]

Dan et al - I have found the instruction CD so no need to send again