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Musical Paradise MP 701 Mark II - Tube rolling recommendations


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10 minutes ago, xlr8or said:

 

The far column in the table below shows the voltage drop for different tube rectifiers. If 5AR4 is giving 325v then you can pretty much work out what a 5U4G and 5Y3 will give. Filter cap uF may also need to be changed.

 

images.jpeg-14.jpg

I have never done all these measurements to the tee largely cause I am still inexperienced with tubes. Went with my gut , some reading and observations here  and a check with Garry. Now am playing songs on my MP and it sings! Didnt notice the tinkle just now. It is as muon says intermittent.

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OK - a few quick comments about valve rolling here. If you reduce the filament voltage then you have more tolerance on the filament current draw. This means you can run higher current draw without ove

I am not a guru but I am a tube lover! For your stated musical preferences you would like to maximise the musical effect of this MP circuit via tube-rolling. I don't know the particular difference the

received my new SGO on father's day. Best father's day gift ever from Auspost. Been listening to it for 4 days now. The preamp is really quiet now. I had buzzing issue previously, but after swapping t

3 minutes ago, Ram18 said:

I have never done all these measurements to the tee largely cause I am still inexperienced with tubes. Went with my gut , some reading and observations here  and a check with Garry. Now am playing songs on my MP and it sings! Didnt notice the tinkle just now. It is as muon says intermittent.

Yeah, side on the side of caution where taking measurements with a powered amp, there are very lethal voltages in there, only do this stuff if you are certain you know what you are doing.

 

And if you know what you are doing always keep one had in ya' pocket.

I say this as It's when a voltage (and it doesn't need to be a lot), passes through the heart is when ya' die from electrocution.

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3 minutes ago, muon* said:

Yeah, side on the side of caution where taking measurements with a powered amp, there are very lethal voltages in there, only do this stuff if you are certain you know what you are doing.

 

And if you know what you are doing always keep one had in ya' pocket.

I say this as It's when a voltage (and it doesn't need to be a lot), passes through the heart is when ya' die from electrocution.

Gosh. Tks for the heads and hearts up! I will certainly leave this part to the proffesionals.

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26 minutes ago, muon* said:

Yeah I get that, Kirk.

 

I'd like to know what the cathode voltage is in this case :D

 

Or the Plate voltage relative to ground.

 

Yep - that would be also helpful to know along with heater and grid voltages. ???

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There is one tube you can use that can take up to 800v on the plates but finding it is harder than finding hen's teeth. It's the Luxman 6240G made by NEC in Japan in the 1970's. It has the same pinout as the 6CG7, 6FQ7, 6922, 6N1P, 6GU7, 6AQ8 etc. Yahoo Aleado is the only place to get them.

 

Screenshot_20210106-001856_Drive.jpg

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1 hour ago, muon* said:

Yeah, side on the side of caution where taking measurements with a powered amp, there are very lethal voltages in there, only do this stuff if you are certain you know what you are doing.

 

And if you know what you are doing always keep one had in ya' pocket.

I say this as It's when a voltage (and it doesn't need to be a lot), passes through the heart is when ya' die from electrocution.

I did the pencil test. Its the 6H30pi tubes giving the tinkle

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6 hours ago, Ram18 said:

I did the pencil test. Its the 6H30pi tubes giving the tinkle

 

If the tinkle sound is annoying you can use these. I personally don't like using tube dampers as they make tubes sound lifeless. However, I understand in this case fitting these maybe necessary.

 

https://herbiesaudiolab.com/collections/tube-dampers

 

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11 hours ago, Ram18 said:

Hahaha. Think I guess thats what am experiencing now perhaps. Relative cooling and warming temps giving the tinkling sounds

I'm old enough to remember a TV set tinkling on shutdown.  It's all part of the sonic bliss.

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Hi I am the bloke having the hum problem after changing the stock gain settings.
Can someone kindly guide me to getting this right.
Unfortunately on setting the  toggles back to stock standard the way the amp was set, i still get hum!
What should i try to do.
To reiterate, i havent messed with anything else
Thanks

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1 hour ago, highcut28 said:

Hi I am the bloke having the hum problem after changing the stock gain settings.
Can someone kindly guide me to getting this right.
Unfortunately on setting the  toggles back to stock standard the way the amp was set, i still get hum!
What should i try to do.
To reiterate, i havent messed with anything else
Thanks

 

You could try swapping the tubes around to see if the hum moves to the other channel. Otherwise, this sounds like an earthing issue and the unit may need servicing.

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7 hours ago, xlr8or said:

 

If the tinkle sound is annoying you can use these. I personally don't like using tube dampers as they make tubes sound lifeless. However, I understand in this case fitting these maybe necessary.

 

https://herbiesaudiolab.com/collections/tube-dampers

 

Thanks for sharing. Will monitor and see how it goes

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19 hours ago, xlr8or said:

 

You could try swapping the tubes around to see if the hum moves to the other channel. Otherwise, this sounds like an earthing issue and the unit may need servicing.

i have successfully adjusted to gain to next to lowest.
Very weird . i still cannot understand how or why that hum came about or how it is now gone.!
It sounds good with volume knob useable from 7 to 12 o clock with current poweramps.
I will cautiously get into some tube rolling - when Russian 6N23P valves arrive 
Any comments on those ?

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@highcut28 I would seriously stick to 6CG7 and 5Y3 bottles at this stage until more is known about the Mk2 version having addressed the excessively high B+ voltages passing through the plates of the 9-pin minis.

 

The intermittent hum issue you have experienced may possibly relate to the excessively high plate voltages coming through the existing set of 9-pin minis.

Edited by xlr8or
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16 hours ago, xlr8or said:

@highcut28 I would seriously stick to 6CG7 and 5Y3 bottles at this stage until more is known about the Mk2 version having addressed the excessively high B+ voltages passing through the plates of the 9-pin minis.

 

The intermittent hum issue you have experienced may possibly related to the excessively high plate voltages coming through the existing set of 9-pin minis.

Thank you Kirk

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  • 3 weeks later...
On 07/01/2021 at 7:22 PM, xlr8or said:

@highcut28 I would seriously stick to 6CG7 and 5Y3 bottles at this stage until more is known about the Mk2 version having addressed the excessively high B+ voltages passing through the plates of the 9-pin minis.

 

The intermittent hum issue you have experienced may possibly relate to the excessively high plate voltages coming through the existing set of 9-pin minis.

Hum returened suddenly after a couple happy weeks.
Took a while to diagnose.
I use  a diy electronic XO for the low pass of semi active drive of a  'JBL 4333'. system 
The hum was caused by faulty DC supply from PSU to the eXO board. 
I have sorted that out. System is  fine now.
So there was nothing at all wrong with the MP.

Question: Can i safely use 2 x 6N23P tubes   ?
These are Reflektor Silver Shields
( will retain the stock Beijing 6N11 at the back
So far everything is stock standard)
Thanks


 

Edited by highcut28
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  • 4 months later...

How's everyone's MP701-MK2? 

 

I was supposed to get a Freya+ but there's none available and there's a backlog at Schiit (my friend ordered in February from the official local dealer and still hasn't received his to date). So instead of waiting I decided to give this preamp a shot. I've just recently got one, and I'm about to tube roll for the first time with a Svetlana winged C 5U4G NOS Tube rectifier (black plate), and three EH630pi from Electro Harmonix. Has anyone rolled these tubes for theirs, and what was your experience like? 

 

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