I must state, this is rather preemptive.
I've just ordered a very cheap and basic kit, simply for VERY CHEAP educational reasons, and the chance to have a valve something-or-other I can stick in various places to see how it effects the sound (pretty badly I expect!!).
To be quite honest, with money not being my friend right now, it's about all I can justify spending on mucking about learning to put together basic hifi stuff. Anyways, this is the potential house fire I've ordered:
6J1 Valve Vacuum Tube Pre-AMP Preamplifier Hifi Stereo Audio Board Musical Fidelity Kit: Amazon.co.uk: Business, Industry & Science
But, once I've learned that it's (total assumption based on price) little more than an education in soldering and how much I can ruin my sound depending on where I put it...
- Can anyone suggest other wallet friendly tube preamps for someone based in the UK? -
I've already got a preamp I'm perfectly happy with, but I'd love to have something that'll probably end up on top of my actual preamp with a Y splitter from the DAC, one pair of RCA's into input one, and one pair through the valve preamp into input two. I don't need multiple inputs, just one pair in and one pair out... Again, just for the fun and education of it - who here doesn't like playing about with audio stuff?
Thanks for reading, and double-thanks if you put any brain-power into it!
Jjams82
I've just ordered a very cheap and basic kit, simply for VERY CHEAP educational reasons, and the chance to have a valve something-or-other I can stick in various places to see how it effects the sound (pretty badly I expect!!).
To be quite honest, with money not being my friend right now, it's about all I can justify spending on mucking about learning to put together basic hifi stuff. Anyways, this is the potential house fire I've ordered:
6J1 Valve Vacuum Tube Pre-AMP Preamplifier Hifi Stereo Audio Board Musical Fidelity Kit: Amazon.co.uk: Business, Industry & Science
But, once I've learned that it's (total assumption based on price) little more than an education in soldering and how much I can ruin my sound depending on where I put it...
- Can anyone suggest other wallet friendly tube preamps for someone based in the UK? -
I've already got a preamp I'm perfectly happy with, but I'd love to have something that'll probably end up on top of my actual preamp with a Y splitter from the DAC, one pair of RCA's into input one, and one pair through the valve preamp into input two. I don't need multiple inputs, just one pair in and one pair out... Again, just for the fun and education of it - who here doesn't like playing about with audio stuff?
Thanks for reading, and double-thanks if you put any brain-power into it!
Jjams82
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Also UK here - interesting little kit, it looks like a valve front end and solid state output (I assume PNP/NPN), if the bits are to be believed. Designing your own amp from scratch (without using a schematic - even if you end up using a known/bought kit will teach you a lot about it. Learning from the kit - trace it's schematic out, use LTSpice and then start looking at the individual components. Nope the solid state looks like it's in the power supply, depending on the schematic you look at.
It's unlikely that the components are pretty, but as long as it's safe and teaches you for £14 that's the important thing. The volume control looks like an itchy/scratchy special.
It's unlikely that the components are pretty, but as long as it's safe and teaches you for £14 that's the important thing. The volume control looks like an itchy/scratchy special.
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No, just a single common cathode triode-strapped 6J1 stage.
Ther transistors are there to make +/-24VDC out of 12VAC.
A student of mine built that exact kit for a project. Given the price, it's a great way to learn soldering. No dangerously high voltages present. We didn't have a 12VAC transformer, so bypassed the rectifier and fed it 12VDC.
We replaced the nasty X7R 1uF ceramic caps with film types, something I recommend you do as well 🙂. We also ended up removing the LEDs because they were a little overbearing.
We replaced the nasty X7R 1uF ceramic caps with film types, something I recommend you do as well 🙂. We also ended up removing the LEDs because they were a little overbearing.
Oh I'm a LONG way from that...
I think you may have overestimated my competence, flattering, but rather pie in the sky!
I'd suspect after I've (hopefully) put this thing together successfully, I may just about be happy building somebody else's preamp design from scratch - no kit, just a schematic and whatever other aids a kind designer may provide... I'm not sure if I'd be comfortable making an actual amplifier playing with stuff that may give me a shock if I make a dumb mistake? Selecting components and a perhaps a little foray into making a DIY PCB (or just chickening out and using one of those universal breadboard style circuit boards with loads of jumper wires on the other side)... Assuming I can make this thing successfully, I hope that's where I'll be at.
Still, if there's a better quality kit out there (presumably more complex so a little more of a challenge to put together and understand) - I'd be keen to give that a shot before going at it from just a schematic!
My response to the quote below might give you a better understanding of where I am with my electronics knowledge...
DontHertzMe said:
See, now I'm going to show my ignorance when it comes to these things, which is the whole point of building the kit I guess...
But, well, which ones are the X7R 1uF ceramic caps? I'd happily follow your advice, if only I knew which ones they are and so how many to order!
Google images suggests they're probably these ones?
So 4 1uf film capacitors should be on my shopping list... Does voltage rating matter, so long as I'm above the minimum requirements?
Doh... Should have scrolled down a bit.
Yep, so they'll be getting replaced by some film caps. Sweet.
Yep, so they'll be getting replaced by some film caps. Sweet.
Thanks for the tips... But I jumped the gun and already ordered some...
Touch wood I didn't get it too far wrong!
Touch wood I didn't get it too far wrong!
Is this a modification, or just a benefit of using film caps instead of those X7R 1uF ceramic caps as mentioned above?
Sorry if it's a dumb question, but you're talking to an absolute beginner at this stuff here.
I'm a electronics-curious farm worker... In my day to day life if something doesn't fit, we cut/weld/hammer it within an inch of its life until it does.
That's the level of knowledge you're dealing with on this thread!
That's the level of knowledge you're dealing with on this thread!
Generally, X7R ceramic caps are a bad idea for signal coupling - they can significantly degrade an audio signal. They're used in this kit because they're inexpensive.
X7R refers to the type of material that constitutes the capacitor, in this case a ceramic compound. Film capacitors are just that, made from layers of plastic film. The plastic can be polyester, polypropylene, or others. In this application the type of film doesn't really matter.
Not all ceramic types are bad, though. NP0 (also known as C0G) ceramic caps can be very good indeed, but you only get them in small values (think picofarads pF and nanofarads nF, not microfarads uF)
No worries at all, we were all beginners at some point 😀
This is a really good introduction to caps in audio and is well worth a read:
Capacitor Characteristics
You construct a parallel composite of the 1 μF. ceramic part and the 0.1 μF. film part. Bypassing a low grade cap. with 10% of a better grade is a well tried technique for improving performance.
^ at first you'd lost me at "parallel composite". But a little bit of thought and I'm wondering... In layman's terms, does that suggest using the higher quality cap AND the lower grade one together (in parallel), rather than simply replacing them? That's what the "parallel composite" part is pointing me towards.
Am I guessing right?
Am I guessing right?
Ta dude, I was just the other day recommending this place to someone very experienced in what I'd consider high end stuff on another forum..
Their reply: "Yeah I know of that one, that lot are miles above my pay grade!"
Me: "It's cool, a lot of them are willing to stoop down to help people up"
And this is a good example of that, much appreciated😀
Not exactly a light read!! I'll read the conclusions later, and bookmark it with the rest of my audio stuff in the hopes that one day it'll be a little clearer.
Thanks again dude.
Does this preamp run from a B+ supply of only 24V DC?
I would consider taking this 'old as the hills' circuit and building it up from scratch, although I'd leave out C3 (leave R3 without C3 across it). That will reduce the gain of the whole thing and let it work okay with typical home audio stuff like those cute little class D amps you can get from China for $30 USD.
That comes from a DIY audio site that's more oriented towards beginners DIY Vacuum Tube (Valve) Amplifier Projects - Hi-Fi Audio but it really came from the old RCA Receiving Tubes Manual, from the 1950s.
Maybe that's not as attractive a deal as getting a whole kit with pcb and most of the parts for less than 20 quid, though.
Unless you're up for a bit more of a challenge...
--
I would consider taking this 'old as the hills' circuit and building it up from scratch, although I'd leave out C3 (leave R3 without C3 across it). That will reduce the gain of the whole thing and let it work okay with typical home audio stuff like those cute little class D amps you can get from China for $30 USD.
That comes from a DIY audio site that's more oriented towards beginners DIY Vacuum Tube (Valve) Amplifier Projects - Hi-Fi Audio but it really came from the old RCA Receiving Tubes Manual, from the 1950s.
Maybe that's not as attractive a deal as getting a whole kit with pcb and most of the parts for less than 20 quid, though.
Unless you're up for a bit more of a challenge...
--
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^I've bookmarked that site - thanks.
As you say, for a "my first valve thing" project, a complete kit (and the replacement caps) for under £20 is just too simple to pass up on. Both as a fun practical and theoretical learning tool - The hope being that I'll be able to figure out (or google) what things are there for as I solder it together bit by bit.
Then it'll be time to start considering collecting up parts and making things from schematics. I've saved that image (along with your R3 / C3 tip) in my folder of audio stuff as a candidate for that.
Which brings up a point now I think of it...
Can any uk folk here recommend a good site for low volume supply of parts for projects like this?
As you say, for a "my first valve thing" project, a complete kit (and the replacement caps) for under £20 is just too simple to pass up on. Both as a fun practical and theoretical learning tool - The hope being that I'll be able to figure out (or google) what things are there for as I solder it together bit by bit.
Then it'll be time to start considering collecting up parts and making things from schematics. I've saved that image (along with your R3 / C3 tip) in my folder of audio stuff as a candidate for that.
Which brings up a point now I think of it...
Can any uk folk here recommend a good site for low volume supply of parts for projects like this?
I forgot to say watfordvalves and billingtons, plus there’s others too give options for tubes (brinmar too).