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Colin Wonfor
16-03-2020, 09:33
Some new toys I am playing with, with A - A/B select and remote cable sense and Balance and Un-balance input Mono amps about 70W max 8Ohm. 1 channel shown here.

Each channel (1 shown) 4 off 47,000uF 2 off 300VA at 15V transformer. 12 output devices, 4 temperature sensors.Ag wire in PTFE for input and output wires. Poly Carbonate input caps. BW 1Hz - 400KHz flat 70W/8R 140W/4R bias from 30W Class A to 5W Class A in A/B mode. SECA driver stage max 140MHz BW to control with ease silly loads. Very expensive to make lots of time and very costly bits.

All working.
75W/8R 140W/4R as it is a pair of Mono Amps
Low A Class setting 5W 8R
High A Class setting 30W/8R
BW 1Hz - 326KHz flat
Balance or Non Balance input 1V full power.
Input RCA 22KR
Input Balance XLR 600R nom (1KR)
Max short term current peak 62 Amps
Damping Factor (silly)

To select amp function there are switches to select Balance and High/Low A Class
THD Low A Class 0.001% into 8R at 20Hz - 50KHz
THD High A Class ( silly) 0.00001% 8R at 10Hz - 100KHz

More tests to be done on sense load input.

From Alan on Audiochews

10:00AM edited 10:01AM Flag
Hi Col, thanks for your comment!

We played a track by PanSonic from Katodivaihe (Cathodephase) called Virta 1. This EP is to all intents and purposes a hifi torture fest, and is interesting if you enjoy electronic music. The bass was literally propulsive, I don't think I experienced anything like this before. Vibration of the wall, sofa, the air between my hands. It's a good thing my neighbor was out! Yet Colin and I could still converse without raising our voices.

Using the amp without its feed forward wiring first, we watched in amazement as the twin aluminium bass drivers performed acrobatics and wondered how the sound wasn't distorting in any appreciable way (I had never seen then move until now). This sound very much the same as the M-100T I had here for a while. Colin smiled the satisfied smirk of a designer who knew he has knocked out out of the park - again.

Adding the feed forward was fascinating. The drivers appeared to barely move in comparison, the twisting at the end of their travel was utterly eliminated. So strange to see a visible manifestation of this feature!

As for the sound, it did that thing you might remember when you first heard a SECA amplifier. That wonderful infusion of subtle detail, superlative speed and convincing warmth, the sound now coupling with and driving the room like you'd not heard before after listening to transistor amps with dampng factors of around a hundred; now a SECA with a DF of thousands could intimately connect you with the music. A performance rather than simply music. Similarly this amplifier can do even better and above a SECA, but at any volume level. This in turn throws the sound image forward and spreads it wider.

We also played 'Love turns forty' by Vienna Teng, which is the other track I think Colin refers to. It's a lovely detailed recording with a double bass. And Lia Ices 'Daphne' for that matter, which also features a string section. Colin is right, the wood body of the cellos and bass was so vivid as to really be striking.

The aspect I'm appreciating most right now is the bass depth and power being present at low volume, the system coupling to my rooms acoustic. The extra control finally sates a desire for scale and presence at any volume, full musical body and texture at low volume with huge imaging. Yet at high volume it appears not to be loud at all (an illusion), but rather bigger. More powerful. More insistent. More - just more. Effortless. Arresting.

This amplifier seems to be so fast, so capable that it doesn't even have to try. The Revels appear to match it's abilities foot for foot, and are just as impressive a piece of engineering. I don't doubt which would ultimately win though, this amp being capable of 64A output into DC! However, I would be Deafened long before that. This is a fascinating exercise in building a system around superb engineering, and the music taking care of itself.

Thank you, Colin. ��"

www.audiochews.com/…/playtime-new-idea-on-severe-amp-contro…
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https://scontent-lhr8-1.xx.fbcdn.net/v/t1.0-9/90277418_2547298735588192_800709739380998144_n.jpg ?_nc_cat=109&_nc_sid=8024bb&_nc_oc=AQloXRyPtMrrlsPLus1QYN_bAOAIXmSbr4CJvlMG1bP uv90qeJbbGZZ1pcRPZ8KP9xY&_nc_ht=scontent-lhr8-1.xx&oh=70bc8df7cca2b67890a007dfef45712c&oe=5E963D03

https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/89785920_2547299415588124_4291259137200750592_o.jp g?_nc_cat=111&_nc_sid=8024bb&_nc_oc=AQnnlhdLyPaM8NLIHFUZr1syQb3-_AnKheQFpwUdCuTXDEI_tH_iJpxI9RDNyaH4sRw&_nc_ht=scontent-lht6-1.xx&oh=273d890d9e64cae2baef0449166d82bf&oe=5E952053

Drawing up new PCB's with the functions plus Softstart, Zero Crossing Low Noise SSR control ( my patent) with DC blocking and RFI filtering, push button operation, So watch this space.

CageyH
16-03-2020, 09:43
The retirement is going well then?

You just can’t keep a good man down.

Colin Wonfor
16-03-2020, 09:55
The retirement is going well then?

You just can’t keep a good man down.

I get bored seen all the "Fringe" watched all Star Trek, "the Good Doctor" Just getting bored and now we old gits have to stay at home for months and months and that is going down well.
Thank goodness I have loads of videos, and music.
All hospital appointments stopped so no lovely nurses to sit and have coffee with a bummer time. Garden to wet so that is out. decorating done so that is on stop.

What it like with you Cagey ?

struth
16-03-2020, 10:00
Scottish govt looks like they wont be locking down oldies...or thats the grapevine.

CageyH
16-03-2020, 10:22
I get bored seen all the "Fringe" watched all Star Trek, "the Good Doctor" Just getting bored and now we old gits have to stay at home for months and months and that is going down well.
Thank goodness I have loads of videos, and music.
All hospital appointments stopped so no lovely nurses to sit and have coffee with a bummer time. Garden to wet so that is out. decorating done so that is on stop.

What it like with you Cagey ?

Schools are closed, I have been asked to work from home, potentially going on one day a week to provide office cover.
Meetings etc. are still going on, so I have lost the commute, but I am still able to work in the comfort of my own home.

We have a holiday planned in April to go to Scotland, but I think that will be cancelled.

walpurgis
16-03-2020, 11:11
I've been phoning round cancelling hospital follow-up appointments after my recent illness. One of them is not answering and insists on playng music at me. I'll see if I can email them.

Colin Wonfor
16-03-2020, 17:22
And get them to change the music, Grateful Dead is the wrong type honest.


https://www.youtube.com/watch?v=ryHatTtaSn4

mikeyb
16-03-2020, 17:25
That looks awesome Colin, fantastic work, how much would the like of that cost?

Not that I'm in the market..... I don't think [emoji23]

Barry
16-03-2020, 23:40
What is the maximum voltage swing at the output? How do they behave into largely reactive loads (i.e. electrostatic speakers)?

Colin Wonfor
17-03-2020, 07:33
PK to PK is about 58V into 8R + 10uF 400V polycarb at 10Hz to 22KHz a silly load then two 10uF in series = 5uF and nasty phase changes no change.

Oh fuses removed and s/c .

Barry
17-03-2020, 08:29
So it would be safe to use with the Quad 57 electroststics. :)

Colin Wonfor
17-03-2020, 12:03
Yes no problem.

Colin Wonfor
17-03-2020, 21:23
Here is the PCB Artwork for the Power Amp two needed in each amp.

https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-9/90331186_2549021115415954_6065664638626824192_o.jp g?_nc_cat=111&_nc_sid=1480c5&_nc_oc=AQkW9zcWuhWmfQKHzPkDHr9Ixck4Fy-J3qlEQRJ8y4Gx0Py4c-CgImlykNEaEb89we4&_nc_ht=scontent-lht6-1.xx&oh=9087cedd263d63331144b81d586149c9&oe=5E955F1D

This is the SS,SSR,DC Blocking. and filter PCB one on each amp.

https://scontent-lhr8-1.xx.fbcdn.net/v/t1.0-9/s960x960/90064240_2549023398749059_7928738309654708224_o.jp g?_nc_cat=110&_nc_sid=1480c5&_nc_oc=AQmJfZch-EL49Uelil6UwmErWsMkTfO7qnMdzVRwpLssp51HhDLIgtDt7ux pVRZvCYg&_nc_ht=scontent-lhr8-1.xx&_nc_tp=7&oh=695b5f6b928bd1aee18fa2a4146c0600&oe=5E95F95D