Briant back,
I just have some simple questions for you...:
1. can I use that for Head unit car CD Player ?
2. what's the difference between car head unit with Home CD Player "output" ?
3. with your "filter output stage WITHIN a CD player" have a much better sound quality ? I do not need any preamp ? does it come from the DAC out that goes into your filter output stage WITHIN a CD player ?
4. I'm thingking using that 12b4 for car preamp later on after suceeded with home, I will build 2, 1 for car and 1 for home.
5. what's your opinion of getting best sound quality from CD Player ? using tube preamp, No Oversampling ? ( I have no idea what's that but people are talk about it)
thanks b4.
regards
cal
I just have some simple questions for you...:
1. can I use that for Head unit car CD Player ?
2. what's the difference between car head unit with Home CD Player "output" ?
3. with your "filter output stage WITHIN a CD player" have a much better sound quality ? I do not need any preamp ? does it come from the DAC out that goes into your filter output stage WITHIN a CD player ?
4. I'm thingking using that 12b4 for car preamp later on after suceeded with home, I will build 2, 1 for car and 1 for home.
5. what's your opinion of getting best sound quality from CD Player ? using tube preamp, No Oversampling ? ( I have no idea what's that but people are talk about it)
thanks b4.
regards
cal
Cal,
1. I suppose you could. I’m not sure what you mean exactly by “head amp” in this case, so I’ll assume you’re referring to the filter and amplifier stage right after the DAC. But take it from a hard-core tube guy; even I wouldn’t bother with tubes for a car application. If I were very concerned about car audio, I’d be more inclined to replace opamps with better ones, use better external switching power amps, and be done with it. Where would you physically place the tube electronics? How would you make 320 volts out of 12 volts? Sure it’s possible, as Milbert has shown, but is it worth the bother?
2. I don’t know. Probably not much. The output voltage standards may vary. But I’m not a car audio expert. Try searching through the CAR audio forum here.
3. It sure sounds better than the stock opamp stage did! I left the original SS stage intact so I can switch between them – the tube output sounds much more alive. You may not need a preamp because I built some extra gain in. If you look at the original posting for the CD stage, you’ll see a resistor divider that could be adjusted to change the output voltage. But you will still need a volume control in your power amp then.
4. Yes, please try the home unit first to see what the construction issues are, and to make sure you like it. If you haven’t built with high voltages before, be sure to read the safety postings.
5. I’m a tube bigot, I admit. I think tubes work better for almost all audio applications, but others whom I respect disagree. As to CD player choices, try searching through the DIGITAL forum. Me, I prefer oversampling players, but my favorite is SACD.
1. I suppose you could. I’m not sure what you mean exactly by “head amp” in this case, so I’ll assume you’re referring to the filter and amplifier stage right after the DAC. But take it from a hard-core tube guy; even I wouldn’t bother with tubes for a car application. If I were very concerned about car audio, I’d be more inclined to replace opamps with better ones, use better external switching power amps, and be done with it. Where would you physically place the tube electronics? How would you make 320 volts out of 12 volts? Sure it’s possible, as Milbert has shown, but is it worth the bother?
2. I don’t know. Probably not much. The output voltage standards may vary. But I’m not a car audio expert. Try searching through the CAR audio forum here.
3. It sure sounds better than the stock opamp stage did! I left the original SS stage intact so I can switch between them – the tube output sounds much more alive. You may not need a preamp because I built some extra gain in. If you look at the original posting for the CD stage, you’ll see a resistor divider that could be adjusted to change the output voltage. But you will still need a volume control in your power amp then.
4. Yes, please try the home unit first to see what the construction issues are, and to make sure you like it. If you haven’t built with high voltages before, be sure to read the safety postings.
5. I’m a tube bigot, I admit. I think tubes work better for almost all audio applications, but others whom I respect disagree. As to CD player choices, try searching through the DIGITAL forum. Me, I prefer oversampling players, but my favorite is SACD.
For those still interested in the 12B4 line stage...?
Yesterday we had a little session where we tried 3 different preamps on a system comprising of a pair of Quad 12L and a EL34 PSE power amp. The preamps were my DIY 12B4, a Sonic Frontiers Anthem Line 1 (IIRC the model, it has 4x6922) and a Diva Classic 300 (3x6SN7). Here's my short review of the event...
The SF had 2 Phllips and 2 Amperex tubes, in short more than $200 worth of tubes alone. It had the lusher vocals of all, some say more body. The sound was pretty good overall, I felt the microdetails was pretty good. Perhaps, thats why people pay so much for those NOS tubes?
On the 12B4,the vocals was not as lush nor "body-ful" But the sound was clearer and cleaner compared to the rest. Details were also clearer, but perhaps micro-details slightly less than the SF (not sure about this), but macro details was the best here. I felt like it was a step closer to the music than the other 2 preamps.
The Diva I felt was less clean in the presentation, I thought it lacked slightly in refinement and smoothness. Perhaps it's the EH tubes being used? A swap to some GEs may improve it. It's probably pretty good, just that it didn't excite me much.
Now, I am not an expert in reviewing equipment or writing reviews. ,so feel free to chip in. What I read about the 12B4 here is that it is neutral and transparent, which I like very much. If cost is a factor, then there is no contest really, the SF is easily 3 times the cost of the 12B4. I have no prior experience with the 6922 series of tubes, so can someone comment on the seemingly lusher sound from the SF? Because of the tubes, circuit, colouration?
BTW, my preamp is the one with the VR150s regulating the B+ somewhere in this thread. Comments anyone?
Yesterday we had a little session where we tried 3 different preamps on a system comprising of a pair of Quad 12L and a EL34 PSE power amp. The preamps were my DIY 12B4, a Sonic Frontiers Anthem Line 1 (IIRC the model, it has 4x6922) and a Diva Classic 300 (3x6SN7). Here's my short review of the event...
The SF had 2 Phllips and 2 Amperex tubes, in short more than $200 worth of tubes alone. It had the lusher vocals of all, some say more body. The sound was pretty good overall, I felt the microdetails was pretty good. Perhaps, thats why people pay so much for those NOS tubes?
On the 12B4,the vocals was not as lush nor "body-ful" But the sound was clearer and cleaner compared to the rest. Details were also clearer, but perhaps micro-details slightly less than the SF (not sure about this), but macro details was the best here. I felt like it was a step closer to the music than the other 2 preamps.
The Diva I felt was less clean in the presentation, I thought it lacked slightly in refinement and smoothness. Perhaps it's the EH tubes being used? A swap to some GEs may improve it. It's probably pretty good, just that it didn't excite me much.
Now, I am not an expert in reviewing equipment or writing reviews. ,so feel free to chip in. What I read about the 12B4 here is that it is neutral and transparent, which I like very much. If cost is a factor, then there is no contest really, the SF is easily 3 times the cost of the 12B4. I have no prior experience with the 6922 series of tubes, so can someone comment on the seemingly lusher sound from the SF? Because of the tubes, circuit, colouration?
BTW, my preamp is the one with the VR150s regulating the B+ somewhere in this thread. Comments anyone?
I would urge you to do the same with a variety of different power amps before drawing any further conclusions. Its likely that your power amp may be more of a limiting factor here. I much prefer the DIY KSA-50 over just about any other solid state or tube amp I've owned. The only excepton to that would be the BAT VK-60 that I used to own. My experience with 6922's is mainly with ARC line stages and I never favored this tube for audio at least in their designs... the sound was almost alwaws a tad dry and britttle. I would reccomend that you get a pair of JAN 12B4 tubes and listen again. The non-JAN tubes generally have allot of microphonics to them over the JAN versions. Also have you added Brian Beck's cathode regulator to your version? And what type of output caps are you using.
Mark
Mark
Hi Mark,
My 12B4A are JAN GE. My output caps are Mundorf Silver/Oil 0.22uf. The Cathode regulator is the LM317? Yes, my circuit is exactly like his with the 2 stacked OD3s, I think Choky drew the circuit.
I do agree with you the power amp may be a concern here, but that's the only one at my friend's place. The 12B4 on my EL84 PP (Magnavox circuit with 6EU7) with my Coral Flat 8 are very nice IMHO, I'm not sure how the SF would sound on my setup though.
That said, I still like my 12B4 linestage a lot, considering the cost, the performance is incredible! I thought some tracks sounded better on the 12B4 because of better clarity and details, sounds like a veil. And I'm not sure if I actually prefer the lusher sound if it's a less accurate reproduction of the music.
Another thing is I had built my preamp with a white cathode follower for a headphone amp, but I thought that would have minimal effect on the preamp stage...
My 12B4A are JAN GE. My output caps are Mundorf Silver/Oil 0.22uf. The Cathode regulator is the LM317? Yes, my circuit is exactly like his with the 2 stacked OD3s, I think Choky drew the circuit.
I do agree with you the power amp may be a concern here, but that's the only one at my friend's place. The 12B4 on my EL84 PP (Magnavox circuit with 6EU7) with my Coral Flat 8 are very nice IMHO, I'm not sure how the SF would sound on my setup though.
That said, I still like my 12B4 linestage a lot, considering the cost, the performance is incredible! I thought some tracks sounded better on the 12B4 because of better clarity and details, sounds like a veil. And I'm not sure if I actually prefer the lusher sound if it's a less accurate reproduction of the music.
Another thing is I had built my preamp with a white cathode follower for a headphone amp, but I thought that would have minimal effect on the preamp stage...
My first post Slightly longish ...
I built a 12B4 stage based on the idea from diyparadise about a year ago. I ended up playing with different operating points and settled on 500R for the cathode (no bypass caps) and 6.3K for the plate resistor and 260v B+ running at around 22-24mA through the tube (interesting coincidence). I am running it with a loftin white 2A3 and absolutely love the combination.
I recently started looking to see if I can improve it further and came across this thread. Great thread went through all the 45 pages straight and learnt a lot, many thanks to the posts by Brian, Mark, Arnoldc, Frank, Zen-Mod and others. I am planning to try these three mods, any comments would be helpful
1) I am going to stick with Brian's sugession of adding the LM317 with 56R resistor at the cathode and add some bypass capacitors.
2) Adding gas shunt regs - my power tranny is rated for 90ma, 700v, PS is tube rectified => LCLC. If I run the 12B4's at 22mA and add gas regs, I am at the limit of the tranny (88mA). I assume this is ok ... it runs hot already Gas tube combo will depend on the next option I am going to try.
One other note, my PS chokes are 30H 40mA (bought them when I was planning to run at 15mA), I understand the inductance will drop considerably at 90mA, but would this be bad in anyway ? Apart from reduced filtering capability. If yes, I will not do gas tubes at this point. Will do it for a rebuild later.
3) Plate choke ... possibly this one here
http://www.lundahl.se/pdfs/datash/1667_68.pdf
Any other sources for plate chokes I should be aware of? Are the ones on ebay any good?
Not sure how to calculate Rp for my operating point but if I assume 1k then for a 100H choke at Rp = 1000 the -1db point is at 6hz. This is good enough right ?
I am assuming I just can't drop a choke instead of the plate resistor. How low should I have to drop my B+ for the choke addition. Any pointers on calculating this would be great. Also I would need some pointers on the gas tube combination required for this B+, if my PS chokes allow it.
Would greatly appreciate some input from you folks. Hopefully I haven't said anything too green so far
Thanks!
Praveen
Slightly longish ...I built a 12B4 stage based on the idea from diyparadise about a year ago. I ended up playing with different operating points and settled on 500R for the cathode (no bypass caps) and 6.3K for the plate resistor and 260v B+ running at around 22-24mA through the tube (interesting coincidence). I am running it with a loftin white 2A3 and absolutely love the combination.
I recently started looking to see if I can improve it further and came across this thread. Great thread went through all the 45 pages straight and learnt a lot, many thanks to the posts by Brian, Mark, Arnoldc, Frank, Zen-Mod and others. I am planning to try these three mods, any comments would be helpful
1) I am going to stick with Brian's sugession of adding the LM317 with 56R resistor at the cathode and add some bypass capacitors.
2) Adding gas shunt regs - my power tranny is rated for 90ma, 700v, PS is tube rectified => LCLC. If I run the 12B4's at 22mA and add gas regs, I am at the limit of the tranny (88mA). I assume this is ok ... it runs hot already
Gas tube combo will depend on the next option I am going to try.One other note, my PS chokes are 30H 40mA (bought them when I was planning to run at 15mA), I understand the inductance will drop considerably at 90mA, but would this be bad in anyway ? Apart from reduced filtering capability. If yes, I will not do gas tubes at this point. Will do it for a rebuild later.
3) Plate choke ... possibly this one here
http://www.lundahl.se/pdfs/datash/1667_68.pdf
Any other sources for plate chokes I should be aware of? Are the ones on ebay any good?
Not sure how to calculate Rp for my operating point but if I assume 1k then for a 100H choke at Rp = 1000 the -1db point is at 6hz. This is good enough right ?
I am assuming I just can't drop a choke instead of the plate resistor. How low should I have to drop my B+ for the choke addition. Any pointers on calculating this would be great. Also I would need some pointers on the gas tube combination required for this B+, if my PS chokes allow it.
Would greatly appreciate some input from you folks. Hopefully I haven't said anything too green so far
Thanks!
Praveen
Holy smoke !
10uF output caps - are you driving a sub 5k load ?
I certainly would not recommend anything near that large for general use. The 0.22uF Mundorfs should be absolutely fine for driving most tube amps, giving a -3db point of 5Hz into 145k and 1.54Hz into a typical 470k load.
Convention is to use the smallest cap that will give you the LF extension you require (a -3db point of 5Hz is used by many designers). Large high quality caps cost a bundle and perform less well than their smaller brethren.
I would also suggest 12B4 owners using a bypassed 317 ccs in the cathode to try comparing a conventional circuit with a ccs replacing the plate resistor and no cathode bypass capacitor. You can use DN2540, 10M45s, or if you want the best try Gary Pimm's latest offering.
pm
10uF output caps - are you driving a sub 5k load ?
I certainly would not recommend anything near that large for general use. The 0.22uF Mundorfs should be absolutely fine for driving most tube amps, giving a -3db point of 5Hz into 145k and 1.54Hz into a typical 470k load.
Convention is to use the smallest cap that will give you the LF extension you require (a -3db point of 5Hz is used by many designers). Large high quality caps cost a bundle and perform less well than their smaller brethren.
I would also suggest 12B4 owners using a bypassed 317 ccs in the cathode to try comparing a conventional circuit with a ccs replacing the plate resistor and no cathode bypass capacitor. You can use DN2540, 10M45s, or if you want the best try Gary Pimm's latest offering.
pm
pengboon, I used to own an Anthem Line 1 and yes they use 6922 and I used Amperex Gold pins on mine. The sound was ok driving my Anthem Amp 1 or 2A3.
I can say that the 12B4 does offer a lot sonically considering the cost of building one. I like mine and it's configured with MOSFET B+ regulation and LM317 bypassed with Black Gate.
I know *this is* a 12B4 thread, but I've been swapping between the 407A pre and 12B4 pre driving my 45 and if I must absolutely choose one, I'd keep the 407A.
I'm pretty sure there are other tubes out there that will sound just as good if not better.
mach1, I'm using 0.5uF on my 12B4 and haven't tried (or have any around) anything beyond 3.3uF. I will solder in my 3.3uF Auricaps tonight and see (or rather hear) what happens.
I have a pair of DIYAudio CCS board ready to plug in to the 12B4 as plate load. I'm going to try the same op points as much as I can compared to the CCS (LM317) on the cathode.
hi praveen, I'm a bit mathematically lost right now. What is you calculated Vp based on you Rp and B+?
You could drop voltage by using 5Y3 or equivalent and, or a choke input PSU.
Using plate choke load will be expensive if you'll use commercial iron. Do you have access to a winder that can make one for you?
Having a higher B+ will give you opportunity later to try CCS as plate load which is much cheaper that a choke load.
Cheers!
I can say that the 12B4 does offer a lot sonically considering the cost of building one. I like mine and it's configured with MOSFET B+ regulation and LM317 bypassed with Black Gate.
I know *this is* a 12B4 thread, but I've been swapping between the 407A pre and 12B4 pre driving my 45 and if I must absolutely choose one, I'd keep the 407A.
I'm pretty sure there are other tubes out there that will sound just as good if not better.
mach1, I'm using 0.5uF on my 12B4 and haven't tried (or have any around) anything beyond 3.3uF. I will solder in my 3.3uF Auricaps tonight and see (or rather hear) what happens.
I have a pair of DIYAudio CCS board ready to plug in to the 12B4 as plate load. I'm going to try the same op points as much as I can compared to the CCS (LM317) on the cathode.
hi praveen, I'm a bit mathematically lost right now. What is you calculated Vp based on you Rp and B+?
You could drop voltage by using 5Y3 or equivalent and, or a choke input PSU.
Using plate choke load will be expensive if you'll use commercial iron. Do you have access to a winder that can make one for you?
Having a higher B+ will give you opportunity later to try CCS as plate load which is much cheaper that a choke load.
Cheers!
Hi Arnoldc,
Did you have the same observation comparing the 12B4 and the Anthem as me? I'm curious the seemingly lusher sound from the Anthem is from the preamp itself or the Amperex tubes? And can you describe more on the 407A?
Mach1,
i'm using FC bypassed with Solen for CCS bypass cap, can/should I try to further improve it with somthing else?
Any other stuff worth trying? Plate choke? Grid biasing?
cheers!
Did you have the same observation comparing the 12B4 and the Anthem as me? I'm curious the seemingly lusher sound from the Anthem is from the preamp itself or the Amperex tubes? And can you describe more on the 407A?
Mach1,
i'm using FC bypassed with Solen for CCS bypass cap, can/should I try to further improve it with somthing else?
Any other stuff worth trying? Plate choke? Grid biasing?
cheers!
pengboon,
You could try using a plate ccs as per the attached circuit diagram and compare it to the cathode ccs you are currently using. As an upgrade to the ccs shown in the schematic you could use this:
http://www.pacifier.com/~gpimm/self_bias.htm
As shown with a 1 uF coupling cap the linestage is fine for driving loads down to about 30k (or even lower if you don't need seismic bass). For driving really low impedance loads the mu out works best.
For a choke loaded version try the H3007 plate choke from handmade electronics (around $20) which works very well with this tube.
pm
You could try using a plate ccs as per the attached circuit diagram and compare it to the cathode ccs you are currently using. As an upgrade to the ccs shown in the schematic you could use this:
http://www.pacifier.com/~gpimm/self_bias.htm
As shown with a 1 uF coupling cap the linestage is fine for driving loads down to about 30k (or even lower if you don't need seismic bass). For driving really low impedance loads the mu out works best.
For a choke loaded version try the H3007 plate choke from handmade electronics (around $20) which works very well with this tube.
pm
Attachments
hi mach1, my 407A pre is very simple. I chose to run it at 160V anode voltage with 250V B+. The plate load is 10K which gives me 250-160 / 10K = 9mA. I used 2.2uF Auricap for coupling because I have a pair I used yellow LED on the cathode to bias it at 2V. I have a switch at the filament to allow me to use it's 6.3V cousins- 2C51, 5670, and WE396A. I attached the loadline I was playing with in MS Paint.
hi pengboon, I don't think I'll ever buy really expensive tubes like those you mentioned so I cannot comment on them for the Anthem Line 1. I also do not prefer too much "body" to me, and only me.
edit: wrong image
I used yellow LED on the cathode to bias it at 2V. I have a switch at the filament to allow me to use it's 6.3V cousins- 2C51, 5670, and WE396A. I attached the loadline I was playing with in MS Paint.hi pengboon, I don't think I'll ever buy really expensive tubes like those you mentioned so I cannot comment on them for the Anthem Line 1. I also do not prefer too much "body" to me, and only me.
edit: wrong image
Attachments
I'm driving a DIY KSA-50 MK-2 with my 12B4. While the 10 mfd capsmay seem large they work extremely well and the LF reproduction is floor ratting! Speakers are Dynaudio Audience 9's. Also I have bypassed both the cathode and ouput coupling caps with multiple other caps, mainly Wondercaps of various values. This 12B4 was my 4th version and so far the longest lived.
We've used this version of the 12B4 for all the Pass Shoot Outs so far. Everyone that comes over and listens ends up building one of them pretty much the same way.
Mark
We've used this version of the 12B4 for all the Pass Shoot Outs so far. Everyone that comes over and listens ends up building one of them pretty much the same way.
Mark
Hi Arnoldc/all,
My Rp ~ 6.3k (paralleled some resistors, was fishing around operating points) , b+ = 260v and my Vp ~ 120v.
Why plate choke ? Plainly curious ... I have read posts where people have been happy with it, I really wanted to try an opt but the gain is barely enough for me right now ... don't want to loose anymore, so thought I'll try the plate choke. Might end up trying gary's ccs too, will post a comparison if I try.
The handmade electronics H3007 from the earlier post looks cheap enough ... at 60H, assuming 2K plate at my operating point, -1db is at 20hz (see attachment). When calculating the B+ required for a choke load do you just use the dcr of the choke eg. 360R*23mA and add it with Vp or is there some other method ? This seems too simple/too low ?
Is this attempt waste of time ? Any pointers will be of great help.
Thanks,
Praveen
My Rp ~ 6.3k (paralleled some resistors, was fishing around operating points) , b+ = 260v and my Vp ~ 120v.
Why plate choke ? Plainly curious ... I have read posts where people have been happy with it, I really wanted to try an opt but the gain is barely enough for me right now ... don't want to loose anymore, so thought I'll try the plate choke. Might end up trying gary's ccs too, will post a comparison if I try.
The handmade electronics H3007 from the earlier post looks cheap enough ... at 60H, assuming 2K plate at my operating point, -1db is at 20hz (see attachment). When calculating the B+ required for a choke load do you just use the dcr of the choke eg. 360R*23mA and add it with Vp or is there some other method ? This seems too simple/too low ?
Is this attempt waste of time ? Any pointers will be of great help.
Thanks,
Praveen
Thanks Arnold,,
That's pretty much where I was thinking of running it.
Praveen, your voltage calculation is spot on. Chokes and transformers can swing the positive voltage that you need to provide for a ccs. I think you will find the comparison between choke and ccs interesting, as they sound quite different. Although the H3007 is not a boutique component, it is an excellent performer with a low DCR.
pm
That's pretty much where I was thinking of running it.
Praveen, your voltage calculation is spot on. Chokes and transformers can swing the positive voltage that you need to provide for a ccs. I think you will find the comparison between choke and ccs interesting, as they sound quite different. Although the H3007 is not a boutique component, it is an excellent performer with a low DCR.
pm
I took these FFT's several months ago. Just found them.
The noise floor of the 12B4A seems lower than the EH6922. The second harmonic distortion is however higher by about 8 db compared to the 6922. Sound card was an ESI Juli@, which is now dead ! Still do not have replacement NJM4580 V opamps !
Output voltage was 1 volt into 100K ohms.
Just put it up FWIW.
The noise floor of the 12B4A seems lower than the EH6922. The second harmonic distortion is however higher by about 8 db compared to the 6922. Sound card was an ESI Juli@, which is now dead ! Still do not have replacement NJM4580 V opamps !
Output voltage was 1 volt into 100K ohms.
Just put it up FWIW.
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