Author Topic: How to Build a killer Amp  (Read 58391 times)

Offline Pixelplay

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Re: How to Build a killer Amp
« Reply #160 on: July 08, 2018, 08:32:12 AM »
This amplifier just keeps on amazing me..... I had not had a listen for a while and I was shocked at how good it is when got back to listening.

Offline stevenvalve

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Re: How to Build a killer Amp
« Reply #161 on: July 09, 2018, 02:23:06 AM »
I agree i cant imagine a better sounding amp than my own UX250 globe beast, its hard to comprehend how an amp could get any better, why because it just sounds real. but there is always better somewhere.......... maybe.
« Last Edit: July 09, 2018, 02:27:06 AM by stevenvalve »

Offline stevenvalve

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Re: How to Build a killer Amp
« Reply #162 on: July 09, 2018, 02:30:57 AM »
Right now i run all Vintage Stuff, 1 Western Electric engraved base 274B, 2 - Mullard Brown Base ECC32, 2 - Holland 45s, nice combo

Offline Pixelplay

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Re: How to Build a killer Amp
« Reply #163 on: July 09, 2018, 08:30:36 AM »
Hi Steve
How many watts are you getting from the 45's?

Offline Pixelplay

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Re: How to Build a killer Amp
« Reply #164 on: July 09, 2018, 02:39:29 PM »
Just hooked up a large valve laboratory supply to play with voltages.......

Offline stevenvalve

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Re: How to Build a killer Amp
« Reply #165 on: July 09, 2018, 02:42:17 PM »
I would think i get about one and a half watts, maybe as much as two. I could get more by increasing the voltage but i seem the have enough. With 2A3 monoplates i get about 3 watts.

Offline stevenvalve

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Re: How to Build a killer Amp
« Reply #166 on: July 09, 2018, 02:43:58 PM »
I would think i get about one and a half watts, maybe as much as two. I could get more by increasing the voltage but i seem the have enough. With 2A3 monoplates i get about 3 watts.
That will be interesting, particularly the change in sound quality.
« Last Edit: July 09, 2018, 06:57:23 PM by stevenvalve »

Offline Pixelplay

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Re: How to Build a killer Amp
« Reply #167 on: July 09, 2018, 03:34:41 PM »
So far the PS B+ is very quiet at 300v

Offline rab

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Re: How to Build a killer Amp
« Reply #168 on: July 11, 2018, 07:16:31 AM »
the suspense is killing me. @pixelplay, please put us out of our misery  ;D

Offline stevenvalve

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Re: How to Build a killer Amp
« Reply #169 on: July 11, 2018, 07:44:56 PM »
Just hooked up a large valve laboratory supply to play with voltages.......
A very good experienced HIFI tuner friend once told me that as he applied more currant and then backed it down to his 300Bs in this amp at some point it will reach a sweet spot where it just sings. Of cause that will depend on many factors even the type and maker of valve and you could apply that to every set of valves in the amp. I must say it is an intriguing test to run a Variac Variable voltage Transformer to the input power of amplifiers to see what effect it had on the sound. I have no doubt it will change markedly and now i also must try it, remember the power point voltage can often change dramatically around the standard 240 volts, i have seen it go very low and as high as 265 volts some days and that must change the regulation of all the internal parts.
« Last Edit: July 11, 2018, 07:50:32 PM by stevenvalve »

Offline Pixelplay

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Re: How to Build a killer Amp
« Reply #170 on: July 14, 2018, 10:54:30 AM »
Here is an image of the lab regulated PS.
Currently running it at 280v.

Please ignore the horrific listening environment as my dedicated room stayed in Melbourne :)

Offline stevenvalve

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Re: How to Build a killer Amp
« Reply #171 on: July 14, 2018, 12:26:46 PM »
They look like RCA-807s in that picture, i have about 40 of those valves and some are real tasty. The great thing is they are good, and they are cheap.

Offline Pixelplay

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Re: How to Build a killer Amp
« Reply #172 on: July 14, 2018, 01:46:25 PM »
They sure are. You need a PS like this...

Offline stevenvalve

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Re: How to Build a killer Amp
« Reply #173 on: August 17, 2018, 05:27:12 PM »
I just changed the amp over to use UX 250 globes again from 245s and thought i will post some hi res pictures for the interested. With the 1930 globes it is indeed sublime. This includes the change to a Western Electric 1930 Engraved base 274A Rectifier and duelund capacitors on the output of the rectifier.
« Last Edit: August 18, 2018, 04:26:54 PM by stevenvalve »

Offline stevenvalve

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Re: How to Build a killer Amp
« Reply #174 on: August 17, 2018, 05:33:03 PM »
I just changed the amp over to UX 250 globe from 45s and thought i post some hi res pictures for the interested. With the 1930 globes it is indeed sublime.
More pictures
« Last Edit: August 17, 2018, 05:35:32 PM by stevenvalve »

Offline stevenvalve

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Re: How to Build a killer Amp
« Reply #175 on: August 17, 2018, 05:42:49 PM »
Last picture
« Last Edit: August 17, 2018, 07:14:06 PM by stevenvalve »

Offline kajak12

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Re: How to Build a killer Amp
« Reply #176 on: August 24, 2018, 05:57:21 PM »
You need a job steve  8)  have you made a will?  :-*
still discovering the link between electronics and audio reproduction.so much to learn and so little time