Thank you 
I guess that if I want to prevent the transformer from melting, I should choose a higher rated transformer
Example :
4 X EL84 @ 60mA each = around 240mA
I suppose that a 160-200 transformer should do the job right ?
(You've probably guessed that I'd do anything to lower the overall
cost of the amp... )
I guess that if I want to prevent the transformer from melting, I should choose a higher rated transformer
Example :
4 X EL84 @ 60mA each = around 240mA
I suppose that a 160-200 transformer should do the job right ?
(You've probably guessed that I'd do anything to lower the overall
cost of the amp... )
Custom transformers
No-one seems to have mentioned it, but transformer manufacturing is a "cottage industry" and you can have "one-offs" made for a very reasonable price if necessary. Old transformers are generally cheaper, but perhaps don't do exactly what you want. If you do go for a new transformer, insist on an electrostatic screen between mains and HT, and also between HT and heaters. It will cost extra, but it's worthwile.
No-one seems to have mentioned it, but transformer manufacturing is a "cottage industry" and you can have "one-offs" made for a very reasonable price if necessary. Old transformers are generally cheaper, but perhaps don't do exactly what you want. If you do go for a new transformer, insist on an electrostatic screen between mains and HT, and also between HT and heaters. It will cost extra, but it's worthwile.
Hi guys !
I was just wondering if a 220V center-tapped transformer is the same thing as a 2 X 110V secondaries connected together ?
Sometimes, I'm really missing some electronics basic knowledge
And oh, by the way, is there any problems when connecting 4ohms speakers to a Gainclone ? (Without forgetting that I shouldn't push it too far)
Thanks !
I was just wondering if a 220V center-tapped transformer is the same thing as a 2 X 110V secondaries connected together ?
Sometimes, I'm really missing some electronics basic knowledge
And oh, by the way, is there any problems when connecting 4ohms speakers to a Gainclone ? (Without forgetting that I shouldn't push it too far)
Thanks !
If you know a few old radio repair shops, they can sometimes have transformers, chokes, tubes and so on just lying around. Or you can scavenge them from old tube gear (PA amps etc.) You can buy an old PA amp with a couple of 6L6 on ebay quite cheaply, which would probebly be enough for 4x EL84.
Takes a bit more imagination to use, but beats paying for new ones...
Pretty much all my iron is "recycled". Transformers seem to last a long, long time if treated well and not overheated.
Takes a bit more imagination to use, but beats paying for new ones...
Pretty much all my iron is "recycled". Transformers seem to last a long, long time if treated well and not overheated.
I know some would differ with me, but _I_ would use a 120:120V isolation transformer and a voltage doubler to get about 300V. (It was good enough for Fisher, McIntosh, HK Citation II...) Or a 120:220V step-up transformer and a full-wave bridge. You'd need 100VA at least for the plate supply, and if you use a toroid (Hammond), you can wind your own secondary for the 6V. In that case, use 130 VA at least. See the amp on my web page for an example: http://www.audiophool.cjb.net/Audio.html
I spent most of my money on my GainClone/Bride of Zen combo lately so the El84 amplifier has been a bit delayed. I got a new job 2 months ago (after 9 months whitout any
)Here's how I've imagined the project :
2 monoblocks
Power Supply : Hammond transformer
270HX 176VA 115V 275-0-275 200mA 5 V@3 A ct 6.3 V@6 A ct OR
272HX 186VA 115V 300-0-300 200mA 5 V@3 A ct 6.3 V@6 A ct using the schematic posted here.
Later, I will work to improve it by using tube rectifier by example.
Output transfomer : Hammond transformer
1650N 60Watts 4,300ohms ct 318 ma. 4-8-16ohms
What do you think about that guys ?
Hi Peter,
While I fully understand what you're pointing at here, there are ways to avoid this "loss of magic".
Granted, it would require a rethinking of the entire design but it can be done.
One of the most magical experiences in my audio career was a ten minutes audition of a Jadis 200_10 // KT88s per channel?_beast that unfortunately went down the blink due to flakey valves but....I'll never, ever forget the uncanny realism the entire setup created back in 1987.
While my own amps are no slouches when it comes to bandwidth and their ability to throw a realistic stereo image, it sure takes a lot attention to detail to make them mimmick that performance...when they do, the magic is there once again and as you may recall the outputstage is composed of 20 triodes in //.
At the expense of bandwidth extension at the frequency extremes I probably can achieve similar results using a flea power SET or PP and a FR speaker a la Fertin, Fostex and such.
You can make choices here according to the powerlevels your room requires and to what extent you want to have "the orchestra in the room" but it can be done with // output valves.
A multiple // run of PX25s will require some major lottery winnings of course...
Elkaid,
Apologies for the OT content..hope you may find it useful nonetheless.
Cheers,
While I fully understand what you're pointing at here, there are ways to avoid this "loss of magic".
Granted, it would require a rethinking of the entire design but it can be done.
One of the most magical experiences in my audio career was a ten minutes audition of a Jadis 200_10 // KT88s per channel?_beast that unfortunately went down the blink due to flakey valves but....I'll never, ever forget the uncanny realism the entire setup created back in 1987.
While my own amps are no slouches when it comes to bandwidth and their ability to throw a realistic stereo image, it sure takes a lot attention to detail to make them mimmick that performance...when they do, the magic is there once again and as you may recall the outputstage is composed of 20 triodes in //.
At the expense of bandwidth extension at the frequency extremes I probably can achieve similar results using a flea power SET or PP and a FR speaker a la Fertin, Fostex and such.
You can make choices here according to the powerlevels your room requires and to what extent you want to have "the orchestra in the room" but it can be done with // output valves.
A multiple // run of PX25s will require some major lottery winnings of course...
Elkaid,
Apologies for the OT content..hope you may find it useful nonetheless.
Cheers,
I don't mind at all
In fact, I like that pretty much. I think that people sharing their experience with other is a great gift and a good opportunity to learn even if it's a bit off topic. It's always connected in some ways.
Even if it's a bit off-topic, people posting pictures and thoughts about their projects, their feelings and their ideas is a great way to improve the relationship between the members of this forum. Sometimes, I have the impression to know some people here just because they openly share their opinions with other people. Think of this forum as a big family.
By example, many guys here have probably began to have an opinion of me just by reading my posts. I admit it, I'm a noob concerning audio electronic but I'm willing to learn but I don't have always the ressources needed to experiment so I ask for suggestions and/or ideas that could make things a bit easier for me. Maybe some ppl here may even consider me as annoying but if it's the case, well maybe those persons have forgot where their passion for audio/video electronics is coming from.
Well, looks like I went a little off topic in my own thread but I just wanted to express how I feel regarding members giving their opinions.
Have a nice day !
Hello Peter and all,
Two thoughts come to my mind:
Purely technically, my first thought looking at the circuit is, plainly put, this can't possibly sound fine, yet it did...the reason it did, IMHO, is very deep class A operation ( remember this was around 1985 and good KT88s were hard to come by, hence the trouble we experienced with KT88s glowing cherry red) and of course the rest of the setup plus the profound know-how of the people setting the stuff up played a major role.
The second thought is: the designers themselves: Andre Calmette and Jean-Paul Caffi for Jadis, Pierre Lurne and yours truly for the turntable,arm and MC.
Volker Kuhn of Audioplan for the cables and God help me for forgetting other helping hands, a few other knowledgeable people such as my friends Patrick Wetli, owner of DaCapo and Costa Metaxas of Metaxas Audio Systems all put in their 2 cents to make it work.
Speakers were my own modded SD3s, a largish, innovative floorstanding three way system in a lush, large hotel room in Luzern, Switzerland.
So? You ask what's all that got to do with it?
Everything:we managed to squeeze the last inch of performance out of an an already promising combo.
As you may know the Jadis amps in those days all shared more or less the same circuitry between the entire range...a circuit I'd laugh away on technical grounds any day of the week but....boy, did this sound lifelike, did this sound like real music? You betcha.
The resemblance to a live concert was simply uncanny.
You want to hear the smaller Jadis such as the JA30 replicate the performance of its bigger brethren? Or, let me put it this way you want all Jadis amps to really make music?
Send me an e-mail and I'll tell the secret, for if I post it here you'll likely pay twice as much for what is already an expensive proposition within a few months.
Remember I put an awful lot of emphasis on music reproduction here, not necesssarily measurements, just sheer music, emotional involvement and spooky real "you are there" feeling.
If those factors are important to you, than yes, I can help.
Now, for overcoming the effect of //ing several output tubes you'll need current drive and high transconductance in spades, all of which isn't always easy to do but penthodes are definitely in the picture no matter what the latest fads are.
More later as I much more prefer to tackle problems on a case by cae basis iso making sweeping generalisations.
Cheers,
Two thoughts come to my mind:
Purely technically, my first thought looking at the circuit is, plainly put, this can't possibly sound fine, yet it did...the reason it did, IMHO, is very deep class A operation ( remember this was around 1985 and good KT88s were hard to come by, hence the trouble we experienced with KT88s glowing cherry red) and of course the rest of the setup plus the profound know-how of the people setting the stuff up played a major role.
The second thought is: the designers themselves: Andre Calmette and Jean-Paul Caffi for Jadis, Pierre Lurne and yours truly for the turntable,arm and MC.
Volker Kuhn of Audioplan for the cables and God help me for forgetting other helping hands, a few other knowledgeable people such as my friends Patrick Wetli, owner of DaCapo and Costa Metaxas of Metaxas Audio Systems all put in their 2 cents to make it work.
Speakers were my own modded SD3s, a largish, innovative floorstanding three way system in a lush, large hotel room in Luzern, Switzerland.
So? You ask what's all that got to do with it?
Everything:we managed to squeeze the last inch of performance out of an an already promising combo.
As you may know the Jadis amps in those days all shared more or less the same circuitry between the entire range...a circuit I'd laugh away on technical grounds any day of the week but....boy, did this sound lifelike, did this sound like real music? You betcha.
The resemblance to a live concert was simply uncanny.
You want to hear the smaller Jadis such as the JA30 replicate the performance of its bigger brethren? Or, let me put it this way you want all Jadis amps to really make music?
Send me an e-mail and I'll tell the secret, for if I post it here you'll likely pay twice as much for what is already an expensive proposition within a few months.
Remember I put an awful lot of emphasis on music reproduction here, not necesssarily measurements, just sheer music, emotional involvement and spooky real "you are there" feeling.
If those factors are important to you, than yes, I can help.
Now, for overcoming the effect of //ing several output tubes you'll need current drive and high transconductance in spades, all of which isn't always easy to do but penthodes are definitely in the picture no matter what the latest fads are.
More later as I much more prefer to tackle problems on a case by cae basis iso making sweeping generalisations.
Cheers,
But I know now that you're the biggest of 'em all.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.