[Guy 13]

At this point of low power one may even no need volume pot with the right sensitivity SPL for changing the sound intensity.
It wil run direct, constant volume, no changes.
A feature not negligible.

Hi FullRangeMan.
I cannot see myself leaving the volume control to the maximum position all the time
even with my flea power Decware 2wpc, it would be way too loud
and you need control over the sound because not all CD-vinyl
are recorded to the same level.
Right now, my 2 wpc Decware volume control is set between 12 and 2pm.
Of course my set up (Bass section) as some help with a 250 watts
ss plate amplifier, that relief the 2wpc Decware from driving heavy hungry
subwoofers.

Guy 13

[FullRangeMan]

Thanks for inform, I unaware this was true to a small 2W amp.

[loving_it]

MULLARD GZ32 CV593

KT 150's  Tong-Sol

CBS 7318

Tesla 12ax7

[jupiterboy]

What's your take on the 150s?

[loving_it]

These are my first tube amps , I just got them Friday . I was going to go with KT88's but upgraded to the 150's so to be honest I never compared them to other output tubes . I have a few hours on these mono blocks and was and they sound just perfect , I cant find any reason to try different tubes at this point .

I read that KT88'S and KT150'S was the best way to go  skipping the 120's    I have very good Bass for sure

[sebrof]

These are my first tube amps , I just got them Friday . I was going to go with KT88's but upgraded to the 150's so to be honest I never compared them to other output tubes . I have a few hours on these mono blocks and was and they sound just perfect , I cant find any reason to try different tubes at this point .

I read that KT88'S and KT150'S was the best way to go  skipping the 120's    I have very good Bass for sure

Nice looking amps.
How many watts from a pair of KT150s?

[loving_it]

65w

[Guy 13]

65w

Hi loving_it.
So at 65wpc/monobloc they are in push-pull pentode?
What speaker do they drive?

Guy 13

[loving_it]

yes , I use them with a pair of Selah Audio Tempesta's

[Docere]

My first completed amp build.


Outer, with EML 2A3M.



Inner.

Thanks for taking the time to look.

Cheers,
Ray

[Guy 13]

My first completed amp build.


Outer, with EML 2A3M.



Inner.

Thanks for taking the time to look.

Cheers,
Ray

Hi Ray.
Nice construction, even if powdered blue is not my favorite color.
I like the under the hood layout, really neet.
You've got quite a lot of capacitors under and on the top of the chassis,
may I ask why you went that way.
What's the output (WPC)?
That look like a power amplifier, then,
where is the pre-amplifier and what does it look like?
What the other components of your system?
Yes, I know, I am very curious.
Well, if you don't ask question, you stay ignorant
and if you ask question you learn something
and show some interest.
Waiting for your answers and comments.

Guy 13
(The curious guy)

[Docere]

Hi Guy,

No problem - I welcome curious!

Firstly, this not an ideal layout - I could not wait until all components were received before doing the final layout for the custom chassis and sub-chassis. But, to answer your questions...

The capacitors on top are ASC Bluelines for the power supply (I'd like the ones supplying the driver stage to be closer to the the plate R). Under the chassis we have the 47uF Mundorf films for output stage cathode bypass; 0.22uF Jupiter wax for coupling; 2x 22uF (per channel) little blue films for input/driver cathode bypass; and finally, 2x 2uF (per channel) beige 2uF NOS PIO for input/driver screen bypass. No electrolytic capacitors.

Yeah, I guess for a low powered amp there are a lot of capacitors. My next build - a refined version of this amp - will not have the coupling capacitors, but will have roughly twice as many capacitors in total.

Feel free to ask any other questions at all.

Cheers,
Ray

[Guy 13]

Hi Guy,

No problem - I welcome curious!

Firstly, this not an ideal layout - I could not wait until all components were received before doing the final layout for the custom chassis and sub-chassis. But, to answer your questions...

The capacitors on top are ASC Bluelines for the power supply (I'd like the ones supplying the driver stage to be closer to the the plate R). Under the chassis we have the 47uF Mundorf films for output stage cathode bypass; 0.22uF Jupiter wax for coupling; 2x 22uF (per channel) little blue films for input/driver cathode bypass; and finally, 2x 2uF (per channel) beige 2uF NOS PIO for input/driver screen bypass. No electrolytic capacitors.

Yeah, I guess for a low powered amp there are a lot of capacitors. My next build - a refined version of this amp - will not have the coupling capacitors, but will have roughly twice as many capacitors in total.

Feel free to ask any other questions at all.

Cheers,
Ray

Hi (Again) Ray.
Please re-read my post and you will see that there are a few questions
that you did not answer.

Guy 13

[Docere]

Hi Guy,

Apologies - I had my mind on dinner!

WPC is roughly 2.5W. I run the outputs at lower dissipation than most - this is better for the EML 2A3M tubes: they (supposedly) sound much better and will last longer! That said, I am planning to try the solid plate 2A3S soon as well.

Yes, this is a power amp only. Volume and input selection are controlled by the DAC...

Other components:  you have seen the speakers and the DAC is a W4S DAC2 for now... I am awaiting delivery of an AMR DP-777 SE. I currently run a older MAC Mini as a source... but that will also be changed to a decent quality streamer by the end of the year (I hope!).

Cheers,
Ray

[sebrof]

My first completed amp build.

Outer, with EML 2A3M.

Thanks for taking the time to look.

Cheers,
Ray

Nice build Ray. Thanks for posting
I've never posted pictures of the underside of mine for good reason 

6c6 drivers?

Have you listened to other 2A3s? I've had several but never the EMLs, just wondering how they compare. My 2 favorites are JJ 2A3-40 and Sophia 2A3 Mesh plates.

[FullRangeMan]

I've never posted pictures of the underside of mine for good reason 

The only reason to shame is if they use PCBs.

[Guy 13]

Hi Guy,

Apologies - I had my mind on dinner!

WPC is roughly 2.5W. I run the outputs at lower dissipation than most - this is better for the EML 2A3M tubes: they (supposedly) sound much better and will last longer! That said, I am planning to try the solid plate 2A3S soon as well.

Yes, this is a power amp only. Volume and input selection are controlled by the DAC...

Other components:  you have seen the speakers and the DAC is a W4S DAC2 for now... I am awaiting delivery of an AMR DP-777 SE. I currently run a older MAC Mini as a source... but that will also be changed to a decent quality streamer by the end of the year (I hope!).

Cheers,
Ray

Hi (Again) Ray.
Thanks for the additional answers.

Guy 13

[sebrof]

The only reason to shame is if they use PCBs.

Are you sure about that??



I've been planning to build another case and rebuild the amp, but I just never get around to it. One of these days...

[Docere]

Nice build Ray. Thanks for posting
I've never posted pictures of the underside of mine for good reason 

6c6 drivers?

Have you listened to other 2A3s? I've had several but never the EMLs, just wondering how they compare. My 2 favorites are JJ 2A3-40 and Sophia 2A3 Mesh plates.

Hi Sebrof,

Thanks for the kind words - a fair bit of planning went into it (and still it can be greatly improved!.. next time). Hey, your build looks fine and I am sure it sounds lovely - I like 6C6 drivers!

Yep, 6c6 - same as you. I have only tried the JAN NU 6C6 at this point. I remember you saying that that most 6c6 tubes sound alike so I have not experimented much with them yet.

I have tried a few different 2A3 tubes:

• Shuggie 2A3C - generally soft, but with a zing through the upper mids. These could benefit from some more running in, but unless they improved a lot, I don't see why I would use them. They are my testing-only tubes.
  
• JJ 2A3-40 - I like these tubes. Powerful (forceful?), big, dynamic and slightly forward sound. With these my system sounded more dynamic and substantial yet less aggressive than when running a nice SS amp. After a while, I felt that the treble and bass seem emphasized with dynamics being a little "too much". Even dynamically compressed music had clarity and drive, but quiet music did not sound sufficiently delicate. These tubes simplify the sound and deliver it with unruly power! I like 'em, and if it were not for their emphasized treble, I may not have tried anything else. On a practical note, the base of one tube seems to be coming loose and pins seem to be a little large in diameter.
  
• EML 2A3M - By reputation, these are best run at a lower plate dissipation than the usual 15W: I run the plate current at ~47mA (used 1K cathode R) for ~12W dissipation. There are also reports of microphonics, but in my amp they did not seem any more microphonic than the JJs (note: the amp has an acetal sub-chassis and Teflon sockets). When run in, the 2A3Ms are musical, highly resolved, expressive and balanced without being smoothed-over or "warm". Instruments have texture and the acoustic space is dense. I missed the dynamics and bass emphasis of the JJs for a while, but no more. In my current system, I sometimes feel the 2A3Ms are a touch more reserved than ideal and they do not flatter dynamically-compressed music. Despite that, I can listen to all kinds of music through them all day long and enjoy every moment, never getting bored or fatigued. My favorites. On a practical note, their build seems far superior to the other two tubes: they are the only tubes that slide in and out of the sockets nicely and I have been able to easily get output noise down to >= 2mV using ac fils.
  

I'm considering trying the EML 2A3S tubes out of curiosity - my guess is that they would provide some dynamics over the 2A3M, but would give up some sheer beauty. I will report if I go this route.

My next amp will be built to get the best out of the 2A3M: direct coupling, low DCR power supply, voltage dividers for tapping the screen voltage and built with improved components and layout etc. It will be interesting to hear what these tubes are capable of, especially dynamically.

Cheers,
Ray[/list]

[FullRangeMan]

Are you sure about that??



I've been planning to build another case and rebuild the amp, but I just never get around to it. One of these days...

Not reason to afraid, its a nice point to point wiring.
No thin wires, no bend wires turn in hi angles(which may broken the copper molecules);
Thanks for posting.