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HELP; DIY PP amp - it's phase splitter, or buy Chineese.

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Hello...

I'm contemplating building my own KT88 or 6L6 push pull amplifier to be used in a bi-amplified system in the bass region (as a "different" but potent alternative to my Lectron JH50). In the mid/highs I will be using a WE-91 type SE amp.

I would really like your comments on this:
I have have done a bit research and found that this DIY project by Pete Millet may seem "promising":
http://www.pmillett.com/push-pull_kt88_class_a_amp_with_universal_driver_pcb.htm
I can swap tubes in this one between KT88 or 6L6, - BUT is it any good? What about input trafo for phase splitting instead of any tubed solution? What is your opinion and recommendation?

Should I just give up on making my own, because amps like these exists, and a pair can be mine for 1700 USD in total: http://www.melodyhifi.com/S88.html

And finally, - another question. Do anybody have any experience with such OPT's as these: http://www.tubebuilder.com/mdcorexfmrs.html

Looking very much forward to your answers and input.

Best Regards
 
hi we91,

I was testing full line of this tube amp from japan.

they work good. sound great.

But still had some space can improve.

If change to nnao amorphous OPT can improve the sound. I will do. Since the phase spitting tubes such as ECC84 was cheap in market U will have many choice such as telefunken, valvo & mullard & reasonable price.

thx

thomas


this is circuit.


An externally hosted image should be here but it was not working when we last tested it.
 
WE91 said:


I would really like your comments on this:
I have have done a bit research and found that this DIY project by Pete Millet may seem "promising":
http://www.pmillett.com/push-pull_kt88_class_a_amp_with_universal_driver_pcb.htm
I can swap tubes in this one between KT88 or 6L6, - BUT is it any good? What about input trafo for phase splitting instead of any tubed solution? What is your opinion and recommendation?

Should I just give up on making my own, because amps like these exists, and a pair can be mine for 1700 USD in total: http://www.melodyhifi.com/S88.html

And finally, - another question. Do anybody have any experience with such OPT's as these: http://www.tubebuilder.com/mdcorexfmrs.html

Looking very much forward to your answers and input.

Best Regards


1. IMHO the "universal driver" is a solid, working solution. Nothing about it strikes as being particularly smart or original; i guess that's the price for being universal.

Otoh, it's not that universal either. I have doubts about its ability to drive convincingly 300B and it seems inappropriate for any kind of nfb i.e. pentodes.

So, you have to live with trioded KT88/6L6 etc as the UL mode is likely to result too high output impedance.

I'll take a pentode KT88 any day, especially in a multi-amped system.


2. The Melody amp is probably quite nice, especially second hand as it's is not likely to keep it's value too well. A valid choice, but think about all the nice iron you can buy for the price - entry level Tango/Tamura/James is quite possible.


3. Never heard of MD cores. Building a nice tube amp is expensive and time consuming. Only the best iron is worth using - see 2.
 
Thank you very much for your answers, Tube-Lover and analog-sa!

I will choose a KT88 amp for the bass in my multi-amp (bi amp) system. I have plenty of time in finding a good solution, though. I do have the 50W PP EL34 Lectron. I will be on the look out for good used PP KT88 amps. If none shows up, I'll just "roll my own" using good iron and a tube rectified psu. Good DIY and kit PP KT88 amp-designs wanted!

Best Regards
Aril
 
... Since I posted this thread, I've found that I'm not going for a Chineese ready-made amp, even if the Melody amps seems a really good choice (some of the best from China?).
I'm going to build it my-self! Thank you, Thomas/Tube Lover for your schematics. I've yet to see them properly, though. I do not know how to amplify:D the pictures. I've put them in Word, and tried to make them bigger, but they're not sharp enough to see. I need help :bawling:
Thank's AndreasS and EC8010 for your comments on the last schematic!
What I "need" is a PP amp thats renown for its rich tone and clarity in the midrange, together with a realy superior, tight and extended bass. My thought has been KT88 or 6L6, - but a really well executed PP DHT amp is also of interest. Although, please do not recommend any 211, 845 or the likes, as I do not like to push the envelope too far on electricution :hot: :cannotbe:

Best Regards
Aril
 
Thank you, Thomas, for your schematics and AndreasS for the link to Audiopro in Japan!
Is this a kit I can buy from this Japaneese firm?
What are the prices? (there's some numbers on the page, are this the prices in yen?).
Is it possible to buy it in loose parts, bit by bit and to get hold of a kit-building description?
Do you know if it's possible to communicate well in english with this firm, Thomas?

I see that this amp uses the 12E1 tubes (with top-caps).
It is many places described as the equivalent to the KT88? Is it "the same" as a KT88, or does it have other qualities?
I haven't found too many makes of the 12E1 tube. Are there many other makers that have made this than ITT/STC and Mazda? What seems to be the best sounding choice? Is this tube manufactured today?

Thomas. Since you have heard this amp, could you try to describe some of your impression of its sonics? How is it's MF and bass and what about definition and soundstage?

Thank you all for your answers and help!

Best Regards
Aril
 
Hi again.

This thread has developed from asking about Pete Millets "universal" driver design with input trafo/phase splitter and the Melody amps, - to a DIY "what PP amp would you recommend" thread. So the heading seem a bit odd now.

I hope I get some more answers on the schematics and availability of the Audiopro 12E1 so I can see if this seems to be a design that stands out. I welcome any suggestions on good PP amps, preferably with available schematics and some description making it clear how to build it. (The schematics of the AP-919B need some more description).
I have found a schematic for a PP 300B on "tubebuilder.com". It does not utilize the 300B PP fully and gives "only" 15W. Does anyone have any comments? http://www.tubebuilder.com/images/schematics/pushpull/300bpp2.gif

Gererally speaking: Would a PP DHT design match a SE DHT sonically better than a PP pentode/tetrode?
Would it be wiser to match a SE 300B with a PP 300B for a bi-amped system? Yes, seems a logical answer, but it needn't be. A good PP as the AP-919B, may just be the better choice when it comes to bass, and it may match a SE 300B well in the midrange. It may also cost a bit less to build a PP pentode/tetrode - thus making it easier to realize. Skimping on quality for parts to more easily get to realize is not an option. I guess a 300B PP amp will cost a lot more in high quality parts.

When something seems to stand out, I will post a new thread with a more appropriate heading when the project is in the planning phase.

Looking forward to your input!

Best Regards
Aril
 
Gererally speaking: Would a PP DHT design match a SE DHT sonically better than a PP pentode/tetrode?


This is the only easy question :) If you are not talking of a sub amp, then yes, matching the tonality between the amps is very important. A PP DHT would be a much better match.


The rest of your questions don't really have a clear answer. And it seems quite improbable that your chosen design will fully meet your expectations. The good bit is that power and output transformers, chasis, PS and a lot of parts are largely reusable between many PP configurations. You just need a few different output tubes and some time to experiment.

Imho no 300B PP design comes close to Lynn Olson's. I have tried all possible active splitters and to me nothing sounds remotely as good as a transformer splitter. But how would you know if this is true unless you try it?
 
Thank you for your input, analog_sa!

I will be searching for the Lynn Olson design on the net, and see what I can find! Great that you, in your answer to me concerning PP DHT amps, also responded to my question on phase splitter transformer! As a rookie DIY amp builder, it was nice of you to mention for me the fact on parts-reusability for PP projects.

Best Regards.
 
Hi again, analog_sa.
I knew there was a bell ringing somewhere when Lynn Olson was mentioned. When searching, I soon found out that I had read about his Amity, Raven, Aurora and Karna earlier. (Of all his constructions I knew his Ariel's the best). http://www.nutshellhifi.com/triode1.html
His amplifier-designs are really very extreme approaches! If I were to go for one of his amps, it would have to be the one easiest to implement without having to build his whole "system". And it is here the problem lies. His designs doesn't seem easily compatible with an "ordinary" pre amp (I use a heavily modified Kaneda) or other power amplifiers. I do not know if I really want to have to build his Raven pre-amp as well, even if it may be a very good design ... Is the Lynn Olson "stuff" as good as it seems to? Has anybody compared?

"My way" ;)
I'm allready in the process of gathering parts for a Brian Cherry/Thorstein Loesch inspired WE91 ... It is going to drive the MF and HF from somewhere between 800 to 1KHz and up. I know these amps do "color" the sound in their own way, and I like it so! I "need" amps that color in a way a bit similar to these in the midrange, but with extended and controlled bass. As analog_sa says, this is a question almost impossible to answer ... Well I'm very happy if someone just points at possible solutions for me, so I can start a process of selection.

Please read this, and you will find out, as I just did, why I must choose PP DHT and most likely with transformer phase splitter (but I'm not yet ready for "the full Oslon" treatment).
http://www.meta-gizmo.com/tri/mag/PULL.html

Best Regards
Aril
 
Hello padpad.

Have you tried to contact She Hi Wang (the constructor/maker) in Hong Kong, Melody Hi Fi in the US or read this fine article with lots of info about Melody and the manufacturer:?
If you own a Melody product, some of these will certainly be of help. If you are looking for their schematics to copy, I guess you'll have to try to get hold of a service-manual, copy someones Melody :cool: or build something else based on KT88's.
The Melody-products are very fine and are, as far as I know, among the very best of Chineese.

Best Regards
Aril
 
tube-lover said:
hi we91,

I was testing full line of this tube amp from japan.

they work good. sound great.

But still had some space can improve.

If change to nnao amorphous OPT can improve the sound. I will do. Since the phase spitting tubes such as ECC84 was cheap in market U will have many choice such as telefunken, valvo & mullard & reasonable price.

thx

thomas


this is circuit.


An externally hosted image should be here but it was not working when we last tested it.

I'm interested in the ECC84 as phase splitter, but I can't read the values. Can you link a larger schematic? thanks!
 
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