Alan Eaton 45 Monoblocks

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FullRangeMan

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Re: Alan Eaton 45 Monoblocks
« Reply #20 on: 5 Jan 2021, 10:47 pm »
I would suggest a inductor  instead coupling caps,  and two power transformers - heating and HV instead out board supply, If funds allow.

jmolsberg

Re: Alan Eaton 45 Monoblocks
« Reply #21 on: 6 Jan 2021, 12:22 pm »
Oh, mum would be the word there! I have some basic soldering skills, would that suffice? Or would you be willing to help advise me should I chose to do that?

I would think so. Maybe some youtube vids and a few practice rounds. Mods certainly aren't necessary with the AE SET but it does lower the noise floor and let you hear further into the music. The TDK volume pots are much smoother, more usable range, and transparent than the alpha brand Alan supplies. Use some quality solder.

https://www.amazon.com/Cardas-Soldering-Eutectic-Silver-Solder/dp/B082J6SH4J/ref=sr_1_2_sspa?crid=CY3HPK7RUHGJ&dchild=1&keywords=cardas+solder&qid=1609935182&sprefix=cardas+%2Caps%2C195&sr=8-2-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExWUtFOVFKMzM1MVJBJmVuY3J5cHRlZElkPUEwMjcyMzgxMU1EUUc2NzUwTUhUNyZlbmNyeXB0ZWRBZElkPUEwOTIyNTI5MUpWSURQWDMyMDQyViZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

Limberpine

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Re: Alan Eaton 45 Monoblocks
« Reply #22 on: 6 Jan 2021, 07:15 pm »
I would think so. Maybe some youtube vids and a few practice rounds. Mods certainly aren't necessary with the AE SET but it does lower the noise floor and let you hear further into the music. The TDK volume pots are much smoother, more usable range, and transparent than the alpha brand Alan supplies. Use some quality solder.

https://www.amazon.com/Cardas-Soldering-Eutectic-Silver-Solder/dp/B082J6SH4J/ref=sr_1_2_sspa?crid=CY3HPK7RUHGJ&dchild=1&keywords=cardas+solder&qid=1609935182&sprefix=cardas+%2Caps%2C195&sr=8-2-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExWUtFOVFKMzM1MVJBJmVuY3J5cHRlZElkPUEwMjcyMzgxMU1EUUc2NzUwTUhUNyZlbmNyeXB0ZWRBZElkPUEwOTIyNTI5MUpWSURQWDMyMDQyViZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

Very good. Yeah, I def will listen to it first to see if its needed, but just wnated to get a handle on others impressions and then weigh, if I should pay the extra dough for the OPS when ready to order from Alan.

jmolsberg

Re: Alan Eaton 45 Monoblocks
« Reply #23 on: 6 Jan 2021, 07:46 pm »
makes complete sense. i didn't touch mine for five months while i got a feel.

EricWe

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Re: Alan Eaton 45 Monoblocks
« Reply #24 on: 7 Jan 2021, 04:27 am »
Just to reiterate - at 2.5 feet away from my speaker it’s dead quiet. That noise you heard about may not be the norm. It’s not for me. If my amp were quieter than it is - it wouldn’t matter as I couldn’t hear it.

Limberpine

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Re: Alan Eaton 45 Monoblocks
« Reply #25 on: 7 Jan 2021, 05:37 am »
Just to reiterate - at 2.5 feet away from my speaker it’s dead quiet. That noise you heard about may not be the norm. It’s not for me. If my amp were quieter than it is - it wouldn’t matter as I couldn’t hear it.

Thanks!

Docere

Re: Alan Eaton 45 Monoblocks
« Reply #26 on: 9 Jan 2021, 11:34 pm »
I have been considering these and wanted to see what other thoughts and experiences have been with them? I've heard there can be some hum issues, so I was considering going with an outboard power supply to help with any potential hum, but will also be running them on La Scalas, so given their sensitivity, I wanted to see if anybody else has run the 2 together or a speaker of similar sensitivity to se what their experience was like?

I've come to view outboard supplies in power amps as a compromise and expense that can be avoided with good design and layout. With any amplifier running AC filaments on DHT tubes, there will be some audible hum. With my 2A3 amp, with AC filaments, driving circa 99dB speakers that are easily "flat" to 50Hz (our line frequency), I can hear hum roughly 45cm (probably less) from the speakers, but no further away. If that level of noise is too great, I suggest using a separate, good quality filament transformer and well-designed DC filament supplies.

Chinese amps.
What woudl be the first class solution?
Its a better circuit assemblage, construction etc
The amp table must be alu or copper, not steel which is magnetic, one of the techniques to reduce background noise that builders use is to bring the circuit closer to the alu table so that it absorbs the parasitic static voltages that circulate inside the amp during use, certainly there are other means of reducing noise.

I agree with a need for better design and construction, though not the method suggested here. The closer components are to conductive metal, the greater the measurable parasitic capacitance. Considering that signal circuitry, in a power amplifier with any touchable conductive part, should be connected to earth, would  “static” voltages be present? As for chassis materials, there is no universal agreement on what is best; it probably depends on what the designer is trying to achieve.
« Last Edit: 10 Jan 2021, 12:47 am by Docere »

FullRangeMan

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Re: Alan Eaton 45 Monoblocks
« Reply #27 on: 10 Jan 2021, 02:06 am »
If condutive metal table is a prob could de used acrylic 8mm as Joule Electra amps, the rec of alu is by Morgan Jones page 153 if I remember well, alu is not prefered  by builders due higher price but its a very interesting opinion from MJ.

EDIT:
According Morgan Jones author in Building Valve Amplifiers/2004 page 85:
Steel is not suitable for the chassis of valve amplifiers. Steel is magnetic, and allows leakage flux from transformers to flowthrough the chassis and induce currents into the pins of the valves. If a steel chassis is unavoidable, induction into the chassis can be greatly reduced by fitting a non-ferrous gasket between transformers and the chassis; 1.5 mm Paxolin is ideal
« Last Edit: 10 Jan 2021, 01:04 pm by FullRangeMan »

Docere

Re: Alan Eaton 45 Monoblocks
« Reply #28 on: 10 Jan 2021, 08:57 pm »
If condutive metal table is a prob could de used acrylic 8mm as Joule Electra amps, the rec of alu is by Morgan Jones page 153 if I remember well, alu is not prefered  by builders due higher price but its a very interesting opinion from MJ.

EDIT:
According Morgan Jones author in Building Valve Amplifiers/2004 page 85:
Steel is not suitable for the chassis of valve amplifiers. Steel is magnetic, and allows leakage flux from transformers to flowthrough the chassis and induce currents into the pins of the valves. If a steel chassis is unavoidable, induction into the chassis can be greatly reduced by fitting a non-ferrous gasket between transformers and the chassis; 1.5 mm Paxolin is ideal

They are good points FRM. I think it depends on techniques, layout etc. How close does the socket need to be to the transformer and how small does the socket need to for currents to be induced into valve pins? What if you don't mount sockets to the chassis and chassis is not close to the valve pins? Plenty of highly-regarded commercial and DIY amps use magnetic chassis without issue - and I don't think it is always due to cost as Morgan suggests. Morgan's goals are minimising risks using simple build techniques in worst-case situations: conservative. I wonder what his thoughts regarding SET amps and full-range drivers would be?

If using a magnetic chassis, I prefer to mount all components, except transformers, on an industrial plastic sub-chassis, well away from the chassis. And I have been using non-magnetic stainless steel for chassis.

FullRangeMan

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Re: Alan Eaton 45 Monoblocks
« Reply #29 on: 11 Jan 2021, 12:39 am »
They are good points FRM. I think it depends on techniques, layout etc. How close does the socket need to be to the transformer and how small does the socket need to for currents to be induced into valve pins?
Its not good a valve to be close the transformer for not overheat the transformer, rectification is a task that generates a lot of heat, rectifier tubes heat up more than others.
What if you don't mount sockets to the chassis and chassis is not close to the valve pins?
I do not have practical experience in distance of socket assemblies, but the distances present in audio amps are not a problem for the activation of the valve, the most careful builders keep the distances as short as possible for the effect of less loss in the musical signal.
Among the audio valves it was found that the 12AX7 has low power, I read on the site of a great builder that this tube cannot drive 1M of interconnect cable, however it suits very well to phono audio stage due the high gain of 100x.

Plenty of highly-regarded commercial and DIY amps use magnetic chassis without issue - and I don't think it is always due to cost as Morgan suggests. Morgan's goals are minimising risks using simple build techniques in worst-case situations: conservative.
Yes, they all use steel and are famous and expensive, its rare a brand use alu in tube amps, however STM Inspire amps use alu chassis made in house but a small one, changing a part will be difficult.
I wonder what his thoughts regarding SET amps and full-range drivers would be?
Iam glad to MJ for he expose this technical detail and others in his book, that has always been secretly hidden by the entire commercial audio world, they do not want the user to know what is good and what is bad so that their products are not exposed to the clinical eye of the audiophool that pays the money that these equips are priced.
If using a magnetic chassis, I prefer to mount all components, except transformers, on an industrial plastic sub-chassis, well away from the chassis. And I have been using non-magnetic stainless steel for chassis.
I think the chassis material can be easily used to model the amp sound.

Docere

Re: Alan Eaton 45 Monoblocks
« Reply #30 on: 11 Jan 2021, 09:44 am »
That is not where I was headed FRM... a lengthy discussion better had face-to-face, or over a beer. Let's not get caught up in that now and guide this back to something relevant to AE 45 amps.