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The point of an 845, 211, 805 amp?
The point of an 845, 211, 805 amp?
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Old Yesterday, 01:29 PM   #251
Bigun is offline Bigun  Canada
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The point of an 845, 211, 805 amp?
If I click the Image until it expands I can see all the parts and part numbers and part values even on my iPad, although I do zoom in when I’m looking at it. uses stacked supplies running the front end at about 400 V and the output at the usual one kilovolt . it uses a 300 B as the driver with interstage transformer to the 845 . The voltage gain stage is a 310 pentode and there are two choices of feedback, one from the interstage transformer, the other from the output transformer, controlled with a simple switch .

SKA: That’s strange I never had those problems with the SKA, although I have only ever built a mono version of it (it also incorporated a couple of tweaks and a completely different printed circuit board which relied on surface mount components), so I can’t comment on the sound stage. if I had any criticism it was in the treble, it seem to lack air, but it was never harsh. I didn’t get much help from Greg after I posted my design improvements to his forum, he deleted my posts showing them. I found the bass performance to be fine but another area of difference may be the power supply.

I don’t know about the sound of big tubes the only one I’ve heard properly is the SV811-10 and it sounded pretty good! but I’ve read a lot of good reviews about amplifiers using the 845 although as we all know the tube alone does not make the sound.
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Last edited by Bigun; Yesterday at 01:37 PM.
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Old Yesterday, 01:52 PM   #252
eduard is offline eduard  Netherlands
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we all know the tube alone does not make the sound. Hello, So true it is the right mix of elements. I remember buying the Tango X10S output transformer for around 600$ directly in Japan in the eighties.

A major element in the amp is the power supply. I would always use a choke and preferably a choke input. The right capacitors are not that easy to find if you are on a tight budget. BUT i think if you are on a tiny budget you should not choose to build a 211/845 amp. One more concern is the weight of these kind of amps.

The reason the Tango had his height where to big higher than the 211 glas bulb so it could be placed upside down. You could go for some kind of the chassis that could be positioned on most of its sides and still have the tubes on view.

Greetings,
Eduard
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Old Yesterday, 01:58 PM   #253
45 is offline 45  Italy
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Quote:
Originally Posted by gabdx View Post
You know 45, the more I think about amps and audio the more I reduce it to this... <snip>
I have a radically different approach. The amplifier is the strong link in any audio system. For most people swapping amps is the easiest thing to do or even the only one. The weakest link is the room, then the source and then the speakers....

There is much more than just colorations (or its opposite) that make the musical sound. But having no control on the room in the first place removes most possibilities....and tone and the usual reviewers parameters are the only left.

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Old Yesterday, 02:54 PM   #254
Bigun is offline Bigun  Canada
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The point of an 845, 211, 805 amp?
this is one of the main reasons I choose mono. And it means only have to build one channel of 845... saves weight at least.
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Last edited by Bigun; Yesterday at 03:07 PM.
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Old Yesterday, 03:27 PM   #255
eduard is offline eduard  Netherlands
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Hello,
For my DRD amp i will go stereo with a big power supply. For my DDDAC had to go stereo too. Made the chassis in a kind '' modular '' approach meaning it can be changed without have to drill extra holes in what is already there. Just change a metal plate into one with a different pattern of holes. The holes to mount it into the chassis will be identical of course.

At this moment it is around 30 kilogrammes. The upcoming modification will involve two big chokes for two little circuits that will be added. Then it will be 40 kilogrammes but happily it will not take it out of the rack every mount because it is above my shoulders. CAN be done after warming up.
Greetings, Eduard
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Old Yesterday, 04:34 PM   #256
gabdx is offline gabdx  Canada
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is this the new R2R dac modules? the stack blue pcbs?
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Old Yesterday, 05:24 PM   #257
JohnnoG is offline JohnnoG  United Kingdom
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For those not familiar with a Mono Amplifier, I used one of my 845 Mono Block Power Supply and Output modules for about 9 months, while it was a 50% complete project. I used it with a 8 Ohm speaker arrangement, as it was suggested the configuration I was using could possibly cause a failure if the 57's were uses as speakers, as the impedance could easily go down to 1 Ohm. I chose to use a Y phono Adaptor, and share both speaker cables into one Banana Plug, so two speakers could be used.

I referred to this as a faux stereo set up. The separation of instrumentalists was very impressive, I had to consult with the designer / builder to get a clarification on what improvements were to be had when the project was complete,the perception was that the performers were all stacked in line, down the centre line of the sound stage. On one Bob Dylan Track, you could sense the harmonica in front of him.

As a stereo set up, the separation is still very impressive, but it has now moved left and right from the centre line into the wider sound stage. I have not picked up on the type of imaging detail, I perceived with the Bob Dylan Harmonica. There have been some great experiences, surpassing my memories of the SQ in other replays using different amplification.

My Designer/ Builder, does not go for bespoke/boutique components, he works with parts that have proven totally reliable, as he sends works all over the globe. I am interested in exchanging some components, so any brands recommended that could be used on the signal path, would be off interest to me. I am not in a position to quote values at present, as the inside of the Output Modules will probably be a no go area for me. Just some thought on tried and tested parts will suffice at present.
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Old Today, 02:19 AM   #258
gabdx is offline gabdx  Canada
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since there is so much information in stereo which combines to recreate the room acoustics and air... how can you listen to mono?

1. listen to one channel in one driver. you have an unbalanced sound, you get all the violins or all the bass, you get half the singers... etc

2. you blend channels? it is going to mix up and destroy a lot of the recording some waves will nul out, etc it is going to be a mess.

3. you listen to only mono records... this brings you back down in time and cuts you from our world lol

I tried to listen to one channel tonight, it is ok, weird not to hear everything which is in the other channel, impossible to balance that sound which has some instruments closed, some far.. just weird, and the recorded room acoustic boundaries are now a dead echo which is annoying, like seeing one eye, impossible to judge distances.
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