The subs are NHT1259 from Madisound
each with a KG5150
http://www.madisound.com/nht10subkit.html
I've got the schematics somewhere and was trying to find them for fdegrove - unable to do so in the confusion of the renovation -
I have been summing the subs together for LFE on Home theater and switching them to Left and Right to use as integrated active woofer for stereo -
The response curve rises too high around 120 or so - can't get to those notes either at the moment.
What to build?? I'm quite open to Fertins - and think they can probably be used with the horns I have on order -
While I missed the last Dixie Bottlehead listening session, due to work - I've been told the horns wowed the group - using dumpster diver drivers from a 1960's Philco open baffle stereo - They liked them better than the Sierra Brooks stuff and originally were bowled over with them in NY with Lowther PM5's as drivers.
So to sum up, you are pointing me more and more in the right direction, Planet 10 - I'm even seriously considering 2A3's as fdegrove suggested at one point - so it's hashing out nicely
Full range - lower power - elegant simplicity in circiutry - musicality with some dynamics and oomph - what circuits and tubes am I looking at?
uh-oh Real Life intrudes
Later
Ken L
each with a KG5150
http://www.madisound.com/nht10subkit.html
I've got the schematics somewhere and was trying to find them for fdegrove - unable to do so in the confusion of the renovation -
I have been summing the subs together for LFE on Home theater and switching them to Left and Right to use as integrated active woofer for stereo -
The response curve rises too high around 120 or so - can't get to those notes either at the moment.
What to build?? I'm quite open to Fertins - and think they can probably be used with the horns I have on order -
While I missed the last Dixie Bottlehead listening session, due to work - I've been told the horns wowed the group - using dumpster diver drivers from a 1960's Philco open baffle stereo - They liked them better than the Sierra Brooks stuff and originally were bowled over with them in NY with Lowther PM5's as drivers.
So to sum up, you are pointing me more and more in the right direction, Planet 10 - I'm even seriously considering 2A3's as fdegrove suggested at one point - so it's hashing out nicely
Full range - lower power - elegant simplicity in circiutry - musicality with some dynamics and oomph - what circuits and tubes am I looking at?
uh-oh Real Life intrudes
Later
Ken L
Peter Daniel said:For the benefit of lower power I guess.
The speakers aren't really differential, but they will be bipoles. My source is primamrily TT, and the TT can be wired so that it is differential (some might use the term balanced). Then into a balanced differential preamp, into diff PP amps (no phase splitting required!) and then thru the OPT to the speakers.
Something like this:
An externally hosted image should be here but it was not working when we last tested it.
into something like this:
An externally hosted image should be here but it was not working when we last tested it.
If done as an integrated amp i figure the last stage of the preamp can disappear making things simpler and one less stage -- might even be able to lose both stages in the LL section (ie just put the output stage of the power amp where the "giant totem" cathode follower is). Of course things will get complicated a bit by the need to bi-amp.
dave
Ken,
crossreading the thread, i would say:
Keep the total system costs in mind, then the Fertins are no longer expensive.
Forget about a tweeter, you won't need one with the Fertin.
Drive the Fertins with a PP amp like Dave posted, using 45 as output tube and a decent OPT, Tango XE-45-8 for instance.
If you want to build the poser amp 3staged (as i do it), you even can tuck the eventual HP for the Fertin inbetween two amp stages and have the XO caps properly biased (as i do it).
This will not be cheap but it will be below what you end up with, building the Linkwitz setup at upper quality level.
And i respectfully doubt you will end up at the same detail resolution compared to the Linkwitz setup. Methinks the 45PP/Fertin setup will eat the Linkwitz setup raw from 100Hz upwards.
Correction concerning the 45: it has been hyped too long meanwhile $35 are asked for a decent used 45 and UX/globe goes >$100 if not >$200.
. And you will have to buy some to find enough buddies: matching is a must with PP.
The Fertin seems to like PP better than SE IMO.
Subwoofer: if you give the Fertin/open baffle setup a chance, i sincerely recommend to go open baffle all the way. Why not use the Linkwitz woofer, it is reputed to have terrific sonics. Or you could do as i intend to do it: use a king-size open baffle and a pair of 18"ers per side.
In the meantime i have gotten my hands on a Russian tube amp delivering 60W and having fancy sonics in the low end. The "hospital-grade" Priboj ampsmirk:, referring to the ugly look, imagine a Soviet-Russian hospital). My buddy Peter Hartmann once re-built it completely, re-working the grounding scheme among other changes (non-starwired->starwired: dramatic improvement) and the owner (or hos wife?) got fed up with the optics. I am very curious if i will end up with the ASKA amp for the subwoofer or if the Russian beauty will make it.
Dave,
i liked Allen's power amp very much although i guess it was another version than the one you posted.
I once was intending to build Allens setup completely. His preamp i had several months for tryout. Did never warm my heart and on the long term i observed i was less and less listening to music.
Tryouts at Munich Triode Mafia meetings have shown the 85R of output impedance are phony. Into a resistive load: yes. Into a transformer: no. So why bother with this complex output circuitry, i asked myself. Allthemore as i did not particuarly like it, from the designer's conceptional POV. Too complex. And those 1µF across the 2M2 (cathode follower tube) are in the signal!! They act as coupling caps, no matter what Allen says. His claim "the whole preamp has two coupling caps only in the signal path" i do not swallow.
Allthemore as he once pointed out how sonically important this cap is. He said, "you can vary the value but don't put junk in".
All,
This whole signal path talk is a gross simplification anyway. As long as we talk SE, the PS's last filter cap acts as coupling cap, undiluted, 100%, unless fancy stuff like choke-loading or CCS loads is used.
For a differential amp this is less and less valid the better the particular stage is balanced and the higher the CMPP and PSRR is. Nevertheless you hear any goof you make in the PS. So: everthing is in the signal and there is no signal path.
Joel,
my sonic experience with good differential tube amps is:
* better low end resolution
* blacker background/better downward dynamic range
* better tone colour distinctability
* tone colour saturation equal.
* sonic influence of PF diminshed.
Oh yes, and the interconnects pick up less hum. To me those advantages weigh enough to give a PP amp design using AD1 (ultra-rare German DHTs) a try. Let's not forget, one has to match tubes used in the same stage and better build matched quads to have both channels behave equal. For that a certain supply is needed unfortunaltely.
crossreading the thread, i would say:
Keep the total system costs in mind, then the Fertins are no longer expensive.
Forget about a tweeter, you won't need one with the Fertin.
Drive the Fertins with a PP amp like Dave posted, using 45 as output tube and a decent OPT, Tango XE-45-8 for instance.
If you want to build the poser amp 3staged (as i do it), you even can tuck the eventual HP for the Fertin inbetween two amp stages and have the XO caps properly biased (as i do it).
This will not be cheap but it will be below what you end up with, building the Linkwitz setup at upper quality level.
And i respectfully doubt you will end up at the same detail resolution compared to the Linkwitz setup. Methinks the 45PP/Fertin setup will eat the Linkwitz setup raw from 100Hz upwards.
Correction concerning the 45: it has been hyped too long meanwhile $35 are asked for a decent used 45 and UX/globe goes >$100 if not >$200.
. And you will have to buy some to find enough buddies: matching is a must with PP.The Fertin seems to like PP better than SE IMO.
Subwoofer: if you give the Fertin/open baffle setup a chance, i sincerely recommend to go open baffle all the way. Why not use the Linkwitz woofer, it is reputed to have terrific sonics. Or you could do as i intend to do it: use a king-size open baffle and a pair of 18"ers per side.
In the meantime i have gotten my hands on a Russian tube amp delivering 60W and having fancy sonics in the low end. The "hospital-grade" Priboj amp
smirk:, referring to the ugly look, imagine a Soviet-Russian hospital). My buddy Peter Hartmann once re-built it completely, re-working the grounding scheme among other changes (non-starwired->starwired: dramatic improvement) and the owner (or hos wife?) got fed up with the optics. I am very curious if i will end up with the ASKA amp for the subwoofer or if the Russian beauty will make it. Dave,
i liked Allen's power amp very much although i guess it was another version than the one you posted.
I once was intending to build Allens setup completely. His preamp i had several months for tryout. Did never warm my heart and on the long term i observed i was less and less listening to music.
Tryouts at Munich Triode Mafia meetings have shown the 85R of output impedance are phony. Into a resistive load: yes. Into a transformer: no. So why bother with this complex output circuitry, i asked myself. Allthemore as i did not particuarly like it, from the designer's conceptional POV. Too complex. And those 1µF across the 2M2 (cathode follower tube) are in the signal!! They act as coupling caps, no matter what Allen says. His claim "the whole preamp has two coupling caps only in the signal path" i do not swallow.
Allthemore as he once pointed out how sonically important this cap is. He said, "you can vary the value but don't put junk in".
All,
This whole signal path talk is a gross simplification anyway. As long as we talk SE, the PS's last filter cap acts as coupling cap, undiluted, 100%, unless fancy stuff like choke-loading or CCS loads is used.
For a differential amp this is less and less valid the better the particular stage is balanced and the higher the CMPP and PSRR is. Nevertheless you hear any goof you make in the PS. So: everthing is in the signal and there is no signal path.
Joel,
my sonic experience with good differential tube amps is:
* better low end resolution
* blacker background/better downward dynamic range
* better tone colour distinctability
* tone colour saturation equal.
* sonic influence of PF diminshed.
Oh yes, and the interconnects pick up less hum. To me those advantages weigh enough to give a PP amp design using AD1 (ultra-rare German DHTs) a try. Let's not forget, one has to match tubes used in the same stage and better build matched quads to have both channels behave equal. For that a certain supply is needed unfortunaltely.
Thanks everyone for your thoughts
You all have given me a good bit to think about.
I've got plenty of time to continue sorting things out on paper.
We've now moved a good bit of furniture into storage and we barely have space to live and eat - then in a week or so the kitchen is torn out - so it'll be a lot of eating out or cooked in a toaster oven.
thanks for helping me clairfy what I needed to be looking at
Sincerely
Ken L
BTW, I thought Tango was out of production - have they started back up - and/or do you know of a source
You all have given me a good bit to think about.
I've got plenty of time to continue sorting things out on paper.
We've now moved a good bit of furniture into storage and we barely have space to live and eat - then in a week or so the kitchen is torn out - so it'll be a lot of eating out or cooked in a toaster oven.
thanks for helping me clairfy what I needed to be looking at
Sincerely
Ken L
BTW, I thought Tango was out of production - have they started back up - and/or do you know of a source
Ken,
Tango is back in business. Availability depends on the model. XE20-S, XE45-5 and XE45-8 are on the list. And some interstages too.
Another suggestion: if you stick to tubes with R_p of around 800R, 300B or 2A3 e.g, then Lundahl has one model having 5k:8R, the LL1663. Said to be a PP alternative to be taken serious at a fraction of the price.
Heck, one should ask Lundahl to make an 8k:8R version of it. But a minimum order of 25 pieces is needed for that.
I do the LL1663 <-> Tango XE45-5 comparison as soon as i have my amp running. Can take a while.
Tango is back in business. Availability depends on the model. XE20-S, XE45-5 and XE45-8 are on the list. And some interstages too.
Another suggestion: if you stick to tubes with R_p of around 800R, 300B or 2A3 e.g, then Lundahl has one model having 5k:8R, the LL1663. Said to be a PP alternative to be taken serious at a fraction of the price.
Heck, one should ask Lundahl to make an 8k:8R version of it. But a minimum order of 25 pieces is needed for that.
I do the LL1663 <-> Tango XE45-5 comparison as soon as i have my amp running. Can take a while.
Fully differential
I had this idea once. It was put to me that it was necessary to have a single ended stage *somewhere* in the signal path. I can't remember the exact reason, but I think it had to do with imbalances produced by the phono cartridge. Was this bad information?
Jeff
planet10 said:
I had this idea once. It was put to me that it was necessary to have a single ended stage *somewhere* in the signal path. I can't remember the exact reason, but I think it had to do with imbalances produced by the phono cartridge. Was this bad information?
Jeff
BALANCED
Jeff,
While some catridges (mostly MM moving magnet) have a ground connection tied to one of the negative output pins and as such render them unbalanced,all MC cartridges are fully balanced and
should provide equal output on all four pins.
So it seems the information you got was incomplete at least.
Gain stages should include a way to balance differences in gain internally.
Best regards,
Jeff,
While some catridges (mostly MM moving magnet) have a ground connection tied to one of the negative output pins and as such render them unbalanced,all MC cartridges are fully balanced and
should provide equal output on all four pins.
So it seems the information you got was incomplete at least.
Gain stages should include a way to balance differences in gain internally.
Best regards,
Frank,
XE20-S is single ended & versatile for 2k5, 3k5, 5k primary and 4-8-16R secondary.
XE45-5 (5k primary) and XE45-8 (8k primary) are PP with 4-8-16R secondary and an additional separate FB secondary.
Lundahl only has 3k or 5k primary and 8R secondary. Which is to be preferred from the technical POV. No idle winding parts around, making the trannie inefficient. Just repeating what *any* Xfrmr expert said to that topic.
XE20-S is single ended & versatile for 2k5, 3k5, 5k primary and 4-8-16R secondary.
XE45-5 (5k primary) and XE45-8 (8k primary) are PP with 4-8-16R secondary and an additional separate FB secondary.
Lundahl only has 3k or 5k primary and 8R secondary. Which is to be preferred from the technical POV. No idle winding parts around, making the trannie inefficient. Just repeating what *any* Xfrmr expert said to that topic.
To dice
Found the tango XE 45-8 for $201 each - didn't say anything about freight
Lundahl 1663 $94 - minimal freight
BFW tamura
http://www2.big.or.jp/~sunaudio/tamura/out1.html
F-685 for about $407 per pair including air freight
Was the Tamura ever a consideration?
Ken L
Found the tango XE 45-8 for $201 each - didn't say anything about freight
Lundahl 1663 $94 - minimal freight
BFW tamura
http://www2.big.or.jp/~sunaudio/tamura/out1.html
F-685 for about $407 per pair including air freight
Was the Tamura ever a consideration?
Ken L
OPT
Hello Ken,
Here is a link to a European distributor specializing in audio xformers to allow you to have a look at the specs.:
http://www.trasformatoriaudio.com/tamura.html
On paper at least quite a few Tamura's outperform Tango's counterparts especially in bandwidth extension at freq. extremes.
I'm not going to discuss price differences since you may well find them a lot cheaper elsewhere.
Here is also an article that should be taken at face value:
http://www.studiomaudio.com/howto.html
There is also a handful of European manufacturers out there able to make excellent xformers but I fear importing those to the U.S.
will make these less attractive due to added taxes and shipping.
Hope this helps,
Hello Ken,
Here is a link to a European distributor specializing in audio xformers to allow you to have a look at the specs.:
http://www.trasformatoriaudio.com/tamura.html
On paper at least quite a few Tamura's outperform Tango's counterparts especially in bandwidth extension at freq. extremes.
I'm not going to discuss price differences since you may well find them a lot cheaper elsewhere.
Here is also an article that should be taken at face value:
http://www.studiomaudio.com/howto.html
There is also a handful of European manufacturers out there able to make excellent xformers but I fear importing those to the U.S.
will make these less attractive due to added taxes and shipping.
Hope this helps,
Ken,
not for me. Unreal as it sounds, i am dremaing of making my amp a product if sonics are satisfying me. And, thinking product, I am going to replace a $$$$ Tango with a $$ Lundahl if sonically possible; i am not going to display them on the top plate anyway.
i am not going to replace a $$$$ Tango with a $$$$ Tamura.
However, the Tamuras are reputed to have good to outstanding sonics, depending on the model and some hardcore Janaese audiophiles prefer Tamura to Tango.
Tango uses C-cores with 0.1mm thick sheetmetal; so does Lundahl. Just, Tango pots, Lundahl not. I tend to agree with Mike LaFevre's opinion on potting (see one early Sound Practises issue). Hate to admit it.
not for me. Unreal as it sounds, i am dremaing of making my amp a product if sonics are satisfying me. And, thinking product, I am going to replace a $$$$ Tango with a $$ Lundahl if sonically possible; i am not going to display them on the top plate anyway.
i am not going to replace a $$$$ Tango with a $$$$ Tamura.
However, the Tamuras are reputed to have good to outstanding sonics, depending on the model and some hardcore Janaese audiophiles prefer Tamura to Tango.
Tango uses C-cores with 0.1mm thick sheetmetal; so does Lundahl. Just, Tango pots, Lundahl not. I tend to agree with Mike LaFevre's opinion on potting (see one early Sound Practises issue). Hate to admit it.
TO POT OR NOT TO POT....
Bernhard,
Thank you for the info on the Tango range.
From what I understand Tango are now restuctured internally and they made changes to the range of product.
All,
I would hate to admit that too,so I don't.
I recall having read this article in SP years ago and I had found similar arguments against potting OPTs elsewhere.
However one can unnerve the arguments easily as well:
What they are afraid of is the stray capacitance caused by the potting resin and the metal can playing havoc with the freq. response of the transformer.
A good transformer however will have this calculated in before potting is applied and so far I haven't been able to observe freq. abberations with high q. brands.
And what about the added capacitance of the leadout wires?
Better not twist those pairs tightly together as I see some people do it.
What they don't tell the public either is that it is both cheaper and easier to design a non-potted transformer as opposed to a potted one.
All too often I see those unpotted transformers arrive with shifted laminations and that is something very undesirable.
I would not feel comfortable with that product when being told to untighten the bolts and to realign the laminations,knowing that these bolts should not be overtightened nor undertightened in the first place and will have a direct effect on its performance.
Another factor is that if windings and laminations are not properly isolated from structureborne and airborne vibrations,they will at some point start to resonate and therefore add distorsion all of their own.
This is especially the case when neither laminations nor windings have been impregnated with high temperature varnish.
Again a lenghty and time consuming process requiring industrial ovens.
In short it takes a lot more effort and time on the manufacturers' side to make a decent potted one then a non-potted OPT would.
Add to that that they want to penetrate an already very competitive niche market and it becomes all of a sudden understandable why they argue against potting anyway.
One way of reducing stray capacitance while still protecting the OPT from the elements is using tightly fitting pots and sealing them with good quality resin at the bottom,or,better still using ceramic end bells as they used to do in the distant past and use a counterfitting bottomplate which is spotwelded to the can.(remember UTC,Partridge and such?)
Now that would be molto expensive,right?
Another good practice is to isolate the OPT from the chassis by using rubber grommets and washers for example.
I am pretty sure that I missed some arguments so I don't claim the list is complete.
I just wanted to bring this point across.
Back to my bombshelter,
P.S.Don't even be tempted to remove the potting on your existing OPTs,please!
Bernhard,
Thank you for the info on the Tango range.
From what I understand Tango are now restuctured internally and they made changes to the range of product.
All,
I would hate to admit that too,so I don't.
I recall having read this article in SP years ago and I had found similar arguments against potting OPTs elsewhere.
However one can unnerve the arguments easily as well:
What they are afraid of is the stray capacitance caused by the potting resin and the metal can playing havoc with the freq. response of the transformer.
A good transformer however will have this calculated in before potting is applied and so far I haven't been able to observe freq. abberations with high q. brands.
And what about the added capacitance of the leadout wires?
Better not twist those pairs tightly together as I see some people do it.
What they don't tell the public either is that it is both cheaper and easier to design a non-potted transformer as opposed to a potted one.
All too often I see those unpotted transformers arrive with shifted laminations and that is something very undesirable.
I would not feel comfortable with that product when being told to untighten the bolts and to realign the laminations,knowing that these bolts should not be overtightened nor undertightened in the first place and will have a direct effect on its performance.
Another factor is that if windings and laminations are not properly isolated from structureborne and airborne vibrations,they will at some point start to resonate and therefore add distorsion all of their own.
This is especially the case when neither laminations nor windings have been impregnated with high temperature varnish.
Again a lenghty and time consuming process requiring industrial ovens.
In short it takes a lot more effort and time on the manufacturers' side to make a decent potted one then a non-potted OPT would.
Add to that that they want to penetrate an already very competitive niche market and it becomes all of a sudden understandable why they argue against potting anyway.
One way of reducing stray capacitance while still protecting the OPT from the elements is using tightly fitting pots and sealing them with good quality resin at the bottom,or,better still using ceramic end bells as they used to do in the distant past and use a counterfitting bottomplate which is spotwelded to the can.(remember UTC,Partridge and such?)
Now that would be molto expensive,right?
Another good practice is to isolate the OPT from the chassis by using rubber grommets and washers for example.
I am pretty sure that I missed some arguments so I don't claim the list is complete.
I just wanted to bring this point across.
Back to my bombshelter,
P.S.Don't even be tempted to remove the potting on your existing OPTs,please!
I'm not above going with Tamura instead of Tango
All too frequently, when a company that has been making a superb high dollar product goes under and reopens under new management - the reissued product may be beneath the previous standard -
I noticed the Tango was rated at 45 watts while the comparable impedance Tamura was about 30 watts -
Would that be a factor running 45's push-pull?
I would go Lundahl first choice if they had the 8K impedance - and may do it anyhow, depending on my cash position at the time of purchase.
Ken l
All too frequently, when a company that has been making a superb high dollar product goes under and reopens under new management - the reissued product may be beneath the previous standard -
I noticed the Tango was rated at 45 watts while the comparable impedance Tamura was about 30 watts -
Would that be a factor running 45's push-pull?
I would go Lundahl first choice if they had the 8K impedance - and may do it anyhow, depending on my cash position at the time of purchase.
Ken l
WATTAGE RATING
Ken,
See you,
In the case of the 45/2A3/6B4G/300B PP it wouldn't matter one bit,the 10 W margin won't play that much of a role.
I haven't run through the Lundahl range for your requirements yet but they have a very good rep.
According to Bernhard they don't carry the 8K you require and 5K is a bit of a mismatch.
Cheers,
Ken,
See you,
In the case of the 45/2A3/6B4G/300B PP it wouldn't matter one bit,the 10 W margin won't play that much of a role.
I haven't run through the Lundahl range for your requirements yet but they have a very good rep.
According to Bernhard they don't carry the 8K you require and 5K is a bit of a mismatch.
Cheers,
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