Bottlehead Forum
Bottlehead Kits => Stereomour II => Topic started by: bpiotrow13 on July 20, 2023, 06:40:25 AM
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I would like to change stock Solens 3.3 uf caps in my Stereomour II. My initial thought was to go with Mundorf Evo Oil 3.30 uf. However i just noticed that the stock Solens are 630v whereas Mundorf Evo Oil 3.30 uf are 350 v.
The question is can i use Mundorf (350v) as a replacement for Solens or higher voltage caps are required? If so, what is the minimum voltage value required for the cap here?
Bogdan
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No, you really should use 600+V rated caps here.
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Understood, many thanks.
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Apologies, just want to be sure, does that mean 600v or above is fine? Or it should be above 600v?
I want to also upgrade the coupling cap, which is 0.1uF @ 630volts. I would like to go with Miflex 0.1 uf 600v. Is that fine?
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600v or greater, for both caps.
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I was same Page you are. Reading previous posts the voltage should not be below 600v. I put miflex 0.1 600 V and 3.3 clarity MR which are 630 btw. Others might probably confirm
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Many thanks All. I have already ordered Miflex 0.1 uf/600 v.
As for the other caps (to replace Solens 0.33 uf) does it need to be 0.33 uf precisely? Or it can be e.g. 0.47 uf?
I am looking for something that would make the sound warmer and see not all brands make 0.33 uf caps. In any case my initial thoughts were Jupiter Copper Foil Paper & Wax, Duelund or Mundorfs but all recommendations welcomed.
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Watch It! 3.3 not .33
3.3uF often already huge size
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Good point, 3.3 uf of course.
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For a warmer sound, PIO caps are the obvious choice, but they will 1) cost you plenty and 2) be so big and heavy you'll have to modify your chassis to get them to fit.
You might try Audyn Cap Plus or Jantzen Z-Superior caps. To my ears, both are warmer and more transparent than Solens. They're also reasonably priced and not huge.
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Anything between 2.5uF and 5uF will work pretty well. There are slight audible differences in the lowest frequencies, but the speaker's impedance variations and the room acoustics are larger factors.
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If you're a little more tolerant to risk than PJ, I think you could get away with a 450V rating for the 0.1uF coupling cap.
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Many thanks again, i think i know all the parameters.
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Encouraged by Your kind responses I have a couple of more questions on Stereomour upgrade.
I have already put in 0.1 uf Miflex caps. Too early to said something definite, but the sound seems to be more 3d and there seem to be more bass.
The next will be Obbligato premium film in oil 4.7 uf (3.3 uf is not available). I have seen Paul recommending this in one of the threads a couple of years ago.
Now my question is whether it is worth to upgrade further. One of my friends suggested changing the signal cables (going from RCA input to selector switch) and power cable (on/off switch – power supply socket). The stock cables are a bit thin, I wonder if changing the cables into thicker ones would make a difference.
I would like to avoid making the mods just to make them, so would be grateful for Your recommendations. I would [refer the sound to be warmer/fuller, but my stereomour already plays nice, surprisingly with only 90 db speakers I made using Sonido full range drivers.
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The 120V power input wiring should be at least 30 AWG (it's far beefier than that in the stock kit). Wire the same diameter as human hair should do the job for the RCA jacks to selector switch, as the current will be well under 1mA flowing through it.
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If you want to warm up the sound one easy way is to install some warm sounding 12AT7s like Mullards or TungSols.
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Thanks, i have 230 v in my grid as i am in EU (Poland). Does it make a diffefence?
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Apologies, You said "The 120V power input wiring should be at least 30 AWG (it's far beefier than that in the stock kit). ". Does it mean that the required power input wiring should be changed from that in the stock kit or i misunderstood and the stock cable is fine (i am not a native speaker)?
I have already change driver tubes into Phillips (Mullards). It plays very well. I am only exploring how far i can/should reasonably go with the mods. I now understand that it is reasonable to change two pairs of capacitors. I refrain for now from doing onther upgrades (like shunt regulator ect as i do not need more clarity in sound, just maybe a bit more charm).
I am really having lots of fun with this kit. I have done Bottlehead Crack and now the Stereomour. I have a vague feeling that the 300b kit may be the next, but just want to explore how far i can go with "warming" the Stereomour as i can not afford the next kit now.
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The stock cable is already very overkill for the incoming AC power, and even more so since you're in a 230V country.
You could try some paper in oil caps to slightly change the flavor of the amp, but the differences tend to be subtle.
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Mundorf's M-Cap Supreme is 600V.