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Re: Remember These?

Posted: Fri Jan 11, 2019 9:03 am
by RhythMick
Have any of us EVER finished a build and thought "yep, wouldn't change a thing" ?

Re: Remember These?

Posted: Fri Jan 11, 2019 11:48 am
by Cressy Snr
RhythMick wrote:
Fri Jan 11, 2019 9:03 am
Have any of us EVER finished a build and thought "yep, wouldn't change a thing" ?
No, but there does come a point when you have to yell at yourself....FERCHRISSAKES STOP!
I reached that point last week and for the first time acted on it. Consequently the situation got rescued. Now theres a thing! :)
You know you've gone too far when your wire ends are charred and your once pristine busbars are covered in chicken shit and lethal spiky bits that prick your finger ends and let copious quantities of blood out.

Re: Remember These?

Posted: Fri Jan 11, 2019 12:02 pm
by RhythMick
Cressy Snr wrote:
Fri Jan 11, 2019 11:48 am
RhythMick wrote:
Fri Jan 11, 2019 9:03 am
Have any of us EVER finished a build and thought "yep, wouldn't change a thing" ?
No, but there does come a point when you have to yell at yourself....FERCHRISSAKES STOP!
I reached that point last week and for the first time acted on it. Consequently the situation got rescued. Now theres a thing! :)
You know you've gone too far when your wire ends are charred and your once pristine busbars are covered in chicken shit and lethal spiky bits that prick your finger ends and let copious quantities of blood out.
Amen brother, Amen

Re: Remember These?

Posted: Fri Jan 11, 2019 12:10 pm
by Nick
RhythMick wrote:
Fri Jan 11, 2019 9:03 am
Have any of us EVER finished a build and thought "yep, wouldn't change a thing" ?
I think the problem is assuming that changes always have to add complexity. The best ones remove it and are normally the result of improved understanding.

Re: Remember These?

Posted: Fri Jan 11, 2019 1:45 pm
by izzy wizzy
This part of the thread is a timely reminder for my own project as I work to make it more complicated; supposedly better. I spent last night thinking do I really need that extra supply for the front end or would some refinement to what I have be a better idea? Should I take my own experience about "wholeosity" and Steve's as well, his experience on this amp. Nick's comment about understanding your stuff can lead to a less complex design and so on. Just because I have the parts to hand doesn't mean I need to stick them in. Food for thought. Thanks Gents, might have saved me from myself :)

Cheers,
Stephen

Re: Remember These?

Posted: Fri Jan 11, 2019 3:37 pm
by Nick
I think you have to be very careful when you plan to make something "better". I think you have to have a clear understanding of what you want to make better, how it will change, and just what better means in the context. Being able to measure and define better in those terms helps a lot. Assuming that better is not just better measurements without any actual audible different.

Re: Remember These?

Posted: Fri Jan 11, 2019 3:47 pm
by Mike H
RhythMick wrote:
Fri Jan 11, 2019 9:03 am
Have any of us EVER finished a build and thought "yep, wouldn't change a thing" ?
Yes, my last one, and the previous one. Image

Nowhere as complex as this one you're doing tho.

Re: Remember These?

Posted: Fri Jan 11, 2019 3:49 pm
by Mike H
Cressy Snr wrote:
Thu Jan 10, 2019 10:52 pm
izzy wizzy wrote:
Thu Jan 10, 2019 7:49 pm
I like mono supplies. There's a wholeness to the sound/presentation that I like and find more musical.
As you say, there's a definite "wholeosity" (copyright Dr Gizmo) to the music with the single power supply.
Image

Re: Remember These?

Posted: Sat Jan 12, 2019 9:18 pm
by Cressy Snr
Had it at Nick's today.
Interesting afternoon, particularly the grid/cathode comparison at full pelt on the dual trace scope. No issue with it trying to run into A2 and going beserk with high drive, so that's one fear put to bed. Interesting to watch the feedback in action on the trace, as the drive level went high.

Not a great deal of power. It'll do a satisfactory 8 Ohms (something a single 6C33C wouldn't) so 13E1 is a great valve for single OTL use, but it will definitely be more comfortable running into 16 Ohms. So that's an incentive to build a 16 Ohm version of the Fane speakers using a Fane Sovereign 12" bass driver to complement the full range driver. Steve S gave me one or two ideas and pointers on that.

Ray should be in for a real treat with the single 13E1 into his 15 Ohm Lowthers.

Thanks go to Nick for a pair of used but good JAN Philips 5687s. I had no idea how knackered my own ones actually were until I fitted these from Nick, in the input driver positions. The distortion performance had been frankly risible on Nick's analyzer, which was perplexing. We traced the issue to the input/drivers, which was why I asked him if he had any spares going.

The sound is much better with the 5687s from Nick. It was still good with the worn out 5687s (I certainly wasn't hearing the poor distortion performance as it was virtually all second and third on the analyzer) It does however sound clearly better with some decent 5687s in. I suppose that's the risk you run when you lash something up with what you have lying about.

The boxed version will have a new pair of Electro Harmonix 6C30pi as input/drivers. These are the same as Bruce uses in the Mini-Beast and are far more linear at low HT voltages than the 5687. I want to keep it simple, so with the 150V of HT I have, the 6C30pi is the no-brainer solution. Could choke load the 5687s of course and I tried that earlier this evening with some Hammond 156, 150H jobbies but the chokes picked up too much hum. 6C30pi it is then. :)

Re: Remember These?

Posted: Sat Jan 12, 2019 10:00 pm
by IslandPink
Sound like a good visit then. You didn't pick up any resistor leads in your socks, though ?

Re: Remember These?

Posted: Sat Jan 12, 2019 10:28 pm
by Cressy Snr
IslandPink wrote:
Sat Jan 12, 2019 10:00 pm
Sound like a good visit then. You didn't pick up any resistor leads in your socks, though ?
No resistor leads in my feet, but a nice listen to a Thorens TD160/SME 3009 Series II/ Hana MC cart, followed by the shifting of a second hand, hardwood fireplace surround with cast iron insert, from the van into the garage. :lol:

Re: Remember These?

Posted: Sat Jan 12, 2019 10:41 pm
by Mike H
Plenty of variety then! :D

Re: Remember These?

Posted: Sat Jan 12, 2019 10:44 pm
by Ray P
Looks like an interesting day Steve.

If you're adopting the 6H30pi our builds could converge as it's available with an octal base so I could easily modify my driver stage PCB. I don't pretend to be competent enough to understand the theory behind your power supply changes to your driver stage but following your lead would simplify my build (and de-risk it given your breadboard work).

Re: Remember These?

Posted: Sat Jan 12, 2019 10:56 pm
by Cressy Snr
Daft as it sounds, all I did was copy Bruce's single power supply on the minibeast. But instead of going CLCLC to the whole thing, I went CLC to the 13E1s, followed by a drop-off for the driver, then an extra RC filter to the input stage, so the stages were decoupled as we went along the PSU. It's just a bog standard practice single three stage valve amp power supply, but it works great.

Re: Remember These?

Posted: Sat Jan 12, 2019 11:00 pm
by Ray P
Are we due another schematic Steve - as you're going to box it? I'll unashamedly plaigerise your work!