Great sounding Tube preamplifier kit recommendation!!

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Currently the best preamp designs are on Ale Moglia's website, Bartola Valves. You can get the latest gyrator from him and the filament regs from Rod Coleman. Then you just need to sort out a chassis and the various fittings. The preamps are in filament bias, and you can use 4P1L, 01A, 26, 10Y etc. I use this as a line stage/input section. Better than Lundahl OPTs.
 
It is easy to build a low impedance, relatively few parts, no feedback, 0.05% distortion pre-amp, however how good is the IMD?

Also, those tubes can have lower thds sometimes at 4 vrms than 0.2 vrms which you will realistically use to drive your power amp. What is the IMD at that power output? for let say 2000hz + 2050hz, how good is the separation of such signals?
 
Aikido

Thinking a preamp not a buffer would help a certain prob I had with my system I wrote to the aikido guy but he read my email and instead of being some kinda asshop businessman, man, what he did was try to help me trouble shoot and suggested a solution that had nothing to do with paying him any bucks (this time anyway) so ya I for now plug for him (I really dont know, but in this one instance I experienced a wee modicum of human kindness[does that still even exist?]) so here I am...plug the aikido man, man. He made no $ off me, I lost none, he did me a solid.
 
Thank you all so much for many replies and recommendations. I have looked over at the k&k audio kit. The complete kit(case+PCB+tube+misc) with no assembly is already at 2k range. It's a bit high for my budge with the tube preamp. However, the spec looks good though better than Bottlehead gear.

hi Wanders, can you please share some insights and your experience with SP14 preamp that you owned ? I have contacted Don Sach for his upgraded full assembled model that also runs to about 2k range as yours. Do you have his upgraded model as well? how do you like the sound? I was about of making a leap of faith to get my hands and feet wet with SP14 DIY kit then I found out about Don's upgrade with everything already assembled/tested, all of the neccessary upgrade and ready to plug and play. I'm still doing more thinking of wether or not buying this upgraded kit from Don. Would love to hear more from people that already had experience with it. So I really appreciate any inputs/ advices that you might have :)

http://www.tubes4hifi.com/SP14.htm

Documentation is a little sketchy and inconsistent, moderator/designer is not much help, not a project for newbies. Nonetheless, I'm very pleased with the outcome.

I put about $2200 into it, but some of that is upgrades and cosmetics. If you're interested, let me know and I can post some pics and more thoughts.



It is easy to build a low impedance, relatively few parts, no feedback, 0.05% distortion pre-amp, however how good is the IMD?

Also, those tubes can have lower thds sometimes at 4 vrms than 0.2 vrms which you will realistically use to drive your power amp. What is the IMD at that power output? for let say 2000hz + 2050hz, how good is the separation of such signals?

hi gabdx, thanks for the reply. IMD ? do you mean the distortion output of my DIY amp?

Here's the manual to my DIY class A alelph J amp http://www.firstwatt.com/pdf/prod_aj_man.pdf

Output distortion of my power amp is about 0.01% at 1khz into 8ohm load
 
Thank you Einric, SufferingArtist, gabdx for introducing Aikido kit to me.

I looked over glassware website but it's a bit confusing to me. Most of the kits were listed with title amplifiers even with line stage. I did not see the full schematic of the kit especially the wiring diagram or what particular transformers/choke, voltage supplies to use for each Aikido kit. Not sure if I want to go that route just yet :) I had DIY experience but mostly SS build. I'm still very new and green with tube so I need more information for my DIY build. Something like what described in Tubelab amp kit. Tubelab SSE | Tubelab

Thanks,
Tom
 
hi Wanders, can you please share some insights and your experience with SP14 preamp that you owned ? I have contacted Don Sach for his upgraded full assembled model that also runs to about 2k range as yours. Do you have his upgraded model as well? how do you like the sound? I was about of making a leap of faith to get my hands and feet wet with SP14 DIY kit then I found out about Don's upgrade with everything already assembled/tested, all of the neccessary upgrade and ready to plug and play. I'm still doing more thinking of wether or not buying this upgraded kit from Don. Would love to hear more from people that already had experience with it. So I really appreciate any inputs/ advices that you might have :)

Hey Tommy,

I think the SP-14 is a wonderful preamp, easily the match of those costing much more. It replaced a Macintosh C-27 (which you can see in one of the pics below). For me, it was a somewhat complicated build, especially as I wanted to incorporate a number of personal preferences. I had built a Salas solid state, m/c phono stage which, for me, was very challenging. The Salas website was extensive, the documentation excellent, and Nick Salas is very helpful and patient. The sp-14 experience was 180 degrees different. So, unless you have some experience, I would avoid trying to build this unit yourself and consider the pre-built version.

I don't have any personal experience with the Don Sachs version, but I have no reason to doubt the reviews; and, at around $2000, it's a very good deal. I checked the Sachs link, but it took me to an older version. I experimented with several coupling caps; If you go with the Sachs option, I would definitely recommend the Mundorfs if they are available. I have tried several tube alternatives and very much like the Slyvania chrome domes shown on the Motram website. But, I'm not sure those shown are exactly what I have, think mine are NOS from the late '40s, but I could check. I notice that there is an option for a remote volume control; that would be a personal choice, but I doubt I would want it.

I've enclose a few pics that I took during the build. Naturally, I made numerous tweaks before I got it right. But it's been running without incident for about a year and I'm very happy.

The SP-14 website is: Advanced Search

Hopefully this brief overview is useful. If you need more detailed information, let me know.

Warren
 

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Thank you all so much for many replies and recommendations. I have looked over at the k&k audio kit. The complete kit(case+PCB+tube+misc) with no assembly is already at 2k range. It's a bit high for my budge with the tube preamp. However, the spec looks good though better than Bottlehead gear.

hi Wanders, can you please share some insights and your experience with SP14 preamp that you owned ? I have contacted Don Sach for his upgraded full assembled model that also runs to about 2k range as yours. Do you have his upgraded model as well? how do you like the sound? I was about of making a leap of faith to get my hands and feet wet with SP14 DIY kit then I found out about Don's upgrade with everything already assembled/tested, all of the neccessary upgrade and ready to plug and play. I'm still doing more thinking of wether or not buying this upgraded kit from Don. Would love to hear more from people that already had experience with it. So I really appreciate any inputs/ advices that you might have :)







hi gabdx, thanks for the reply. IMD ? do you mean the distortion output of my DIY amp?

Here's the manual to my DIY class A alelph J amp http://www.firstwatt.com/pdf/prod_aj_man.pdf

Output distortion of my power amp is about 0.01% at 1khz into 8ohm load

no, I was questioning the use of DHT (direct heated triodes) in a preamplifier regarding IMD = intermodulation distortion. DHT have higher noise and lots of micro-phonics effects which should be detrimental to the sound unless you are looking for those effects. The pass lab is a warm sounding amplifier and I doubt you need more icing on the cake!

The aikido is very similar to the tube4hifi, except tube4hifi has some regulator for both channels which is very overkill, i think.

I personally prefer a good carbon pot to the gang volume pots which pick up more RF and have higher noise and more fragile. just my 2c$ so you could buy the basic kit and save a lot of money.
 
no, I was questioning the use of DHT (direct heated triodes) in a preamplifier regarding IMD = intermodulation distortion. DHT have higher noise and lots of micro-phonics effects which should be detrimental to the sound unless you are looking for those effects.

I want to know what makes DHT different from the other tubes, so I also would like to see the IMD plot of DHT preamps at different levels. THD seems to be low with them.
 
Thank you so much Warren for the prompt details, photos, review, thoughts and feedbacks on SP-14. I think I make up my mind to pick SP-14. Funny that you mentioned Salas Phono stage since I also built that phono stage not too long ago. It has alot of little matching details of Jfets, LED, transistors to be done but it was a fun project. The sound is amazing. Very comparable and somewhat better than Pearl 2 phono stages in some aspects. I contacted Don Sachs and he had one of the newly built upgrade model like the one you built with Tube showcased on top of the wooden chassis from one of his customer on sale with everything updated including tubes/output caps, rectifier and some of his own recipes of wiring. Your post just help me make up my mind to go with that option instead. It will save me some time to build + I have everything updated without having to look hard and source the parts like other projects in the past.

Hey Tommy,

I think the SP-14 is a wonderful preamp, easily the match of those costing much more. It replaced a Macintosh C-27 (which you can see in one of the pics below). For me, it was a somewhat complicated build, especially as I wanted to incorporate a number of personal preferences. I had built a Salas solid state, m/c phono stage which, for me, was very challenging. The Salas website was extensive, the documentation excellent, and Nick Salas is very helpful and patient. The sp-14 experience was 180 degrees different. So, unless you have some experience, I would avoid trying to build this unit yourself and consider the pre-built version.

I don't have any personal experience with the Don Sachs version, but I have no reason to doubt the reviews; and, at around $2000, it's a very good deal. I checked the Sachs link, but it took me to an older version. I experimented with several coupling caps; If you go with the Sachs option, I would definitely recommend the Mundorfs if they are available. I have tried several tube alternatives and very much like the Slyvania chrome domes shown on the Motram website. But, I'm not sure those shown are exactly what I have, think mine are NOS from the late '40s, but I could check. I notice that there is an option for a remote volume control; that would be a personal choice, but I doubt I would want it.

I've enclose a few pics that I took during the build. Naturally, I made numerous tweaks before I got it right. But it's been running without incident for about a year and I'm very happy.

The SP-14 website is: Advanced Search

Hopefully this brief overview is useful. If you need more detailed information, let me know.

Warren

Hi Gabdx,

This SP-14 preamp is using 6SN7 tube and they are indirectly heated so I think the sound should be good not "detrimental" to the final outcome I hope :)
no, I was questioning the use of DHT (direct heated triodes) in a preamplifier regarding IMD = intermodulation distortion. DHT have higher noise and lots of micro-phonics effects which should be detrimental to the sound unless you are looking for those effects. The pass lab is a warm sounding amplifier and I doubt you need more icing on the cake!


Hi Kodabmx,

Thank you so much for the reply and the link. Yes, I have checked out the kit. The kit/PCB looks great. Simple and straightforward. However, for me to get started with DIY build, I need more information regarding actual BOM materials, schematic with actual numeric values of each components, power supply information values for each rail and to each tube, transformer type/choke, wiring diagram especially for the power supply to the main PCB. I cannot find any of those information from Aikido website. They have the link to Build Guide or manual but the link is not working. Since this is the 1st Tube DIY project, I'm not so very familiar with power supply wiring schematic as with SS. Maybe, if I have built a few tube DIY projects, I can come back to Aikido kit or even doing my own P-P tube project one of those days. Shouldn't be too bad. I did a few P-P projects with SS before. It was fun!

Have you checked these out?

GlassWare Line Stage & Headphone Amplifiers Kits and PCBs

My favourite for line is a CCDA. Using 6N1P.

Cheers.
 
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I want to know what makes DHT different from the other tubes, so I also would like to see the IMD plot of DHT preamps at different levels. THD seems to be low with them.

Well, first of all there is nothing special with DHT, it is a basic triode which uses the cathode as the source of heat, the heater is the cathode.

There is nothing special about 0.05% distortion at 1khz 10Vrms output, who uses 10Vrms to drive a power amplifier anyway? (0.002 Watts into input resistor of power amp)

I built a preamp which has 0.01% distortion (no feedback) at 2.5 Vrms which is louder than I will ever need, usually need only 1 Vrms in peaks.

The point that I am making is that you don't need big power tubes to drive a preamplifier signal and the THD is not really what you look for but more the ability to amplify at low voltages complex signals without blending the sound, which has nothing to do with square waves or Thds.
 
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Sprags, sounds like you have used both. I have a completed Tubes4HiFi Sp-9 line stage and an Aikido octal line stage kit under construction.
The SP-9 line stage sounds unbelievable, it was a big step up in my Mac MC40 monoblock/Altec system. The SP-9 uses 12AX7 tubes instead of the SP-14 6SN7 tubes.
Anyway, can you elaborate on why it was better?
Thank you.

BillWojo
 
I was questioning the use of DHT (direct heated triodes) in a preamplifier regarding IMD = intermodulation distortion. DHT have higher noise and lots of micro-phonics effects which should be detrimental to the sound unless you are looking for those effects.

I've been using nothing but DHTs for 8 years, inputs and outputs. They sound clearer than any indirectly heated tube I ever used. It's like lifting a veil on the sound, and the timbre of vocals, piano and acoustic instruments is closer to the original to my ears, and since I've been playing music live for 50 years, orchestral and jazz, I have a pretty good idea of how the original instruments sound live. But if you have other priorities that's fine with me.
 
no, I was questioning the use of DHT (direct heated triodes) in a preamplifier regarding IMD = intermodulation distortion. DHT have higher noise and lots of micro-phonics effects which should be detrimental to the sound unless you are looking for those effects.

That might likely happen with poor filament supply (typical AC supply or poor DC supply) and poor mechanical mount as typical in many DIY objects.....

I prefer solid state class A for sources both phone and digital but from line level it really starts to make little difference if things are done right. So at line level both tubes and SS can be the right choice. At power level tubes are better for me.
 
I've been using nothing but DHTs for 8 years, inputs and outputs. They sound clearer than any indirectly heated tube I ever used. It's like lifting a veil on the sound, and the timbre of vocals, piano and acoustic instruments is closer to the original to my ears, and since I've been playing music live for 50 years, orchestral and jazz, I have a pretty good idea of how the original instruments sound live. But if you have other priorities that's fine with me.

Thanks for sharing this with me. I am in total ignorance of DHT sound. I wish I had your preamplifier and make all the test until we find why it sounds clearer.

The most stringent test I can imagine is to pass arbitrary wave forms at different frequencies and see the output. I test at 192khz in 24 bit which reveals a lot of information about the sound.
 
You have far better measurement skills than I have - I just have my ears! My objectives are clarity and timbre - not necessarily what others want, e.g. soundstage means nothing to me. If you are curious, have a look at Bartola Valves website. Lots of cutting edge stuff there. It's very different to build - the circuits contain a lot of solid state but none the worse for that - the gyrators and filament supplies come in kits which aren't too difficult to assemble. Tubes like 26 and 01A are plentiful on eBay and sound great.
 
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