ValveWave-1 My first Tube Project

waltsongs · 9th June 2006, 02:33 PM

Wont win any prizes with it, but it’s one of the best projects I’ve done. It’s built mostly from old AT Computer Power Supply parts. The 12AX7 is biased at +300 Volts, so it’s not a starved tube design. It sounds a lot better than using my Mackie Mixer as a preamp. I’m already working on a Two-Tube design with a Cathode follower to drive the soundcard input. I think I will get a better impedance match that way.

Walt

ValveWave-1

Eli Duttman · 9th June 2006, 03:33 PM

Walt,

L_RD knows you have plenty of current available in the B+ rail. It seems to me that a ZVN0545A source follower, as described in MOSFET Follies, would achieve your impedance matching purpose. Grafting the FET onto your existing stuff doesn't seem all that difficult.

ZVN0545A data sheet here.

You mentioned "flavor". A great way to try a NOS tube at low cost is the 7058. GE built 7058s can be had under $10. RCA 7058s cost more.

Edit: Added 7058 remarks

waltsongs · 9th June 2006, 05:21 PM

That looks interesting, I'll have to try it on a breadboard and see how it sounds. I'll probably stick with 12AX7's as they are easy to come by. I use Chineese brands when I'm breadboarding, but have a small supply of NOS RCA tubes that I use for recording. I'll have a link up within a week or so to the first song that I've recorded using this preamp. I really like the sound. Thanks for the reply and information.

Walt

waltsongs · 19th June 2006, 02:40 PM

I have a sound sample available for my first preamp. It's a section from my latest composition (I'm not much of a picker)...
http://www.safossils.com/valvewave.mp3

alexmoose · 19th June 2006, 03:11 PM

Walt,

I love the look, and the schematic, as I am not a guitar playet, I really have no use for one personally, however I have a very good friend who doesn't DIY, and this looks like a great project that he would find very interesting. I admire this projects form, as well as it's function. however may I ask, did you make your own PC boards? or did you buy them somewhere?

Trout · 19th June 2006, 05:21 PM

Quote:

Originally posted by waltsongs
I have a sound sample available for my first preamp. It's a section from my latest composition (I'm not much of a picker)...
http://www.safossils.com/valvewave.mp3

Any Clips or short recordings of the unit dry? (no Effects)

I might just pop one of these together.
Trout

waltsongs · 19th June 2006, 07:47 PM

The only effect I added was software reverb to one channel. I'll post a dry MP3 when I get a chance. I cooked the circuit boards up myself using positive etch transfers. If you decide to build one, the transformer windings go all the way around the ecore. They are not wound around the center like a normal power transformer. I'm going to post some more pictures of the transformer as I'm working on a two-tube model already. It uses 12AV6/12AU7, (surplus that I already have). I'll be using point to point wiring on it.

Thanks,
Walt

Trout · 20th June 2006, 02:25 AM

Hey, I think dynamically it sounds very good, In fact, very impressive.

That software reverb sounds alot like a bit of chorus also. Nice

What guitar was used? Sounds very acoustic.
As far as the power supply, I am thinking of using a portable hard drive case and making it portable for use with my laptop.

I have looked at a few power transformers from triad and am thinking it might be possible to use the
McTube Style power supply and only mount 1 transformer internally. Use the second externally with the chassis jack already in the case.

Might take a bit of tinkering to get the right combo of transformers but feasible.

Then I can just throw it in my laptop bag and take it on trips

Trout

waltsongs · 20th June 2006, 01:53 PM

The power supply you referenced shows B+ at 140. I'm running the 12AX7 at +300 Volts. You can change the resistors to bias the tube correctly at that voltage, but I'm not sure if it will sound the same.

I use an Epiphone 12-string with a lawrence soundhole pickup.

Best of luck,
Walt

Trout · 20th June 2006, 04:26 PM

Quote:

The power supply you referenced shows B+ at 140. I'm running the 12AX7 at +300 Volts. You can change the resistors to bias the tube correctly at that voltage, but I'm not sure if it will sound the same.

Yeah, I figured I would use a mismatched pair, 120V/12V@ 2a into a 220V/9V@2a. Should give enough extra voltage to get closer then a few resistor tweaks.

Worse case scenerio I can just get a cheap small plate transformer from Triad.
I really like the portability factor.

Nice sounding Guitar BTW, Ever try any electrics in the unit yet? Maybe a Strat?
Trout

9th June 2006, 02:33 PM	#1
waltsongs diyAudio Member Join Date: Mar 2006 Location: Arizona	ValveWave-1 My first Tube Project Wont win any prizes with it, but it’s one of the best projects I’ve done. It’s built mostly from old AT Computer Power Supply parts. The 12AX7 is biased at +300 Volts, so it’s not a starved tube design. It sounds a lot better than using my Mackie Mixer as a preamp. I’m already working on a Two-Tube design with a Cathode follower to drive the soundcard input. I think I will get a better impedance match that way. Walt ValveWave-1

9th June 2006, 03:33 PM	#2
Eli Duttman diyAudio Member Join Date: Apr 2004 Location: Plainsboro, NJ	Walt, L_RD knows you have plenty of current available in the B+ rail. It seems to me that a ZVN0545A source follower, as described in MOSFET Follies, would achieve your impedance matching purpose. Grafting the FET onto your existing stuff doesn't seem all that difficult. ZVN0545A data sheet here. You mentioned "flavor". A great way to try a NOS tube at low cost is the 7058. GE built 7058s can be had under $10. RCA 7058s cost more. Edit: Added 7058 remarks __________________ Eli D.

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9th June 2006, 05:21 PM	#3
waltsongs diyAudio Member Join Date: Mar 2006 Location: Arizona	That looks interesting, I'll have to try it on a breadboard and see how it sounds. I'll probably stick with 12AX7's as they are easy to come by. I use Chineese brands when I'm breadboarding, but have a small supply of NOS RCA tubes that I use for recording. I'll have a link up within a week or so to the first song that I've recorded using this preamp. I really like the sound. Thanks for the reply and information. Walt

19th June 2006, 02:40 PM	#4
waltsongs diyAudio Member Join Date: Mar 2006 Location: Arizona	I have a sound sample available for my first preamp. It's a section from my latest composition (I'm not much of a picker)... http://www.safossils.com/valvewave.mp3

19th June 2006, 03:11 PM	#5
alexmoose diyAudio Member Join Date: Mar 2006 Location: Michigan	Walt, I love the look, and the schematic, as I am not a guitar playet, I really have no use for one personally, however I have a very good friend who doesn't DIY, and this looks like a great project that he would find very interesting. I admire this projects form, as well as it's function. however may I ask, did you make your own PC boards? or did you buy them somewhere?

19th June 2006, 07:47 PM	#7
waltsongs diyAudio Member Join Date: Mar 2006 Location: Arizona	The only effect I added was software reverb to one channel. I'll post a dry MP3 when I get a chance. I cooked the circuit boards up myself using positive etch transfers. If you decide to build one, the transformer windings go all the way around the ecore. They are not wound around the center like a normal power transformer. I'm going to post some more pictures of the transformer as I'm working on a two-tube model already. It uses 12AV6/12AU7, (surplus that I already have). I'll be using point to point wiring on it. Thanks, Walt

20th June 2006, 02:25 AM	#8
Trout diyAudio Member Join Date: Nov 2004 Location: Midwest Madman	Hey, I think dynamically it sounds very good, In fact, very impressive. That software reverb sounds alot like a bit of chorus also. Nice What guitar was used? Sounds very acoustic. As far as the power supply, I am thinking of using a portable hard drive case and making it portable for use with my laptop. I have looked at a few power transformers from triad and am thinking it might be possible to use the McTube Style power supply and only mount 1 transformer internally. Use the second externally with the chassis jack already in the case. Might take a bit of tinkering to get the right combo of transformers but feasible. Then I can just throw it in my laptop bag and take it on trips Trout

20th June 2006, 01:53 PM	#9
waltsongs diyAudio Member Join Date: Mar 2006 Location: Arizona	The power supply you referenced shows B+ at 140. I'm running the 12AX7 at +300 Volts. You can change the resistors to bias the tube correctly at that voltage, but I'm not sure if it will sound the same. I use an Epiphone 12-string with a lawrence soundhole pickup. Best of luck, Walt

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