Toy11 VT4C 211AMP -1
Start to prepare the components and box.
After estimate the box is not big enough for two channel circuit and components.
So decide to make Mono-Mono Amplifier.
Estimate the placement for good signal quality and easy hand make.
High voltage must keep long distance with small signal circuit.
Final estimate placement picture.
Double check rear panel placement.
Start to prepare the components and box.
After estimate the box is not big enough for two channel circuit and components.
So decide to make Mono-Mono Amplifier.
Estimate the placement for good signal quality and easy hand make.
High voltage must keep long distance with small signal circuit.
Final estimate placement picture.
Double check rear panel placement.
Hi Singa :
Attach schematic for your reference.
Did your ever DIY VT4C before?
Mr211's blog
Mr211's Blog - Yahoo!?????
Attach schematic for your reference.
Did your ever DIY VT4C before?
Mr211's blog
Mr211's Blog - Yahoo!?????
Hi asterhoa,
No I have not diy 211/VT4C but I have one pair.No budget/money
for it.
I have one pair of cheap Hammond GSE125 10K ohm output for non hifi use,so I am quite familiar with big transmitting tube like 211,845,805.( How difficult to make good sounding amplifier).
I see you are using 6C45 as driver,not that it does not work but as you know 6C45 can oscillate and the luck of the circuit?. (if you don't use grid stopper resistor).I have friend who diy 211 pushpull(6C45 driver) with Tamura outputs not too bad but I feel can be better.
Since you have not start assembly maybe you may want to consider using
another DHT like 2A3 or 300B as driver because only a big tube can give the
required current when VT4C/211 needs it (transients) plus the quality of signal.Or at least use pentode like 6L6 or EL34 wired as triode.
If you can try using AC heater ( afraid of hum?) for 211/VT4C as it will give a more emotional flavour to the sound.( kan cheuh in chinese).Have you heard of Sakuma?
Visit his website at "direct heating" and find out.Also use oil caps(motor run type) instead of electrolytic caps for power filter?
But since you have already bought all your components you will probably
use them anyway.Wish you good luck on your project. Singa
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Hi!
The 6C45 is a poor choice for a driver tube IMHO. It will offer no headroom and will dominate the sound of the amp. I wrote an article about my view on this topic:
VinylSavor: Gain, Headroom and Power
Best regards
Thomas
The 6C45 is a poor choice for a driver tube IMHO. It will offer no headroom and will dominate the sound of the amp. I wrote an article about my view on this topic:
VinylSavor: Gain, Headroom and Power
Best regards
Thomas
Thanks for your suggestion.
Did your had ever hear Ongaku 211 before?
How about the Ongaku 211 sound color?
If your have Ongaku 211 schematic Pls send to me...thanks!
They fully hand mark all component like silver resistor, silver capacitor even silver transformer..... that's really out my ability.
http://tw.myblog.yahoo.com/jw!9frLFy6fAkV0gBy_oZT_geG5fC24WQ--
Thanks for your reply.
After check ....
spec. 6C45Pi plate-resister only 930ohm, gain-factor about 52.
spec. 5842/417A plate-resister 1.8kohm, gain-factor about 43.
So I choice 6c45pi.
Because I don't like soundcolor of 6sn7,12ax7,12au7 there are also have big plate-resister too and I want try somthing different.
AsterKao
Hi asterhoa,
No I have not diy 211/VT4C but I have one pair.No budget/money
for it.
( How difficult to make good sounding amplifier).
I see you are using 6C45 as driver,not that it does not work but as you know 6C45 can oscillate and the luck of the circuit?. (if you don't use grid stopper resistor).I have friend who diy 211 pushpull(6C45 driver) with Tamura outputs not too bad but I feel can be better.
Since you have not start assembly maybe you may want to consider using
another DHT like 2A3 or 300B as driver because only a big tube can give the
required current when VT4C/211 needs it (transients) plus the quality of signal.Or at least use pentode like 6L6 or EL34 wired as triode.
If you can try using AC heater ( afraid of hum?) for 211/VT4C as it will give a more emotional flavour to the sound.( kan cheuh in chinese).Have you heard of Sakuma?
Also use oil caps(motor run type) instead of electrolytic caps for power filter?
But since you have already bought all your components you will probably
use them anyway.Wish you good luck on your project. Singa
Thanks for your suggestion.
Your have one pair of VT4c/211 is a good start.
I think your better keep enough distance for 211 and don't too close other component because 211 is very hot and Output transfermer is a key to effect sound color.
I had ever hear about 5 sets sound color of pushpull 211 and sound not goog so I make a choice to design Single-End 211.
I choice 6C45pi base it's hi-gain factor.
Your mention about afraid of hum.... this must trad-off.
My speaker sensivity about 97db after test distance 25cm almost not hear hum I could accept it. ....just as your say ..more emotional flavour to the sound.
Power use C-L-C filter type to genrater high voltage but the cap. is not oil cap.
First C use 3 pcs of Spreque 40uf/600 cascade to 1800V.
Second C 4 pcs od cap. cascade to 1800V.
Because I setup VT4c working in 1250V (Spec. Max. voltage).
Mr211's Blog - Yahoo!?????
Hi asterkoa,
Seems like you are an experienced diyer so you know what you want.I don't have link for the Ongaku schematic but is easy to find because
it is commonly refered to by diyer but not practical to build because you can't
get silver wired output transformers
plus their in-house made silver caps and tantalum resistors.Of course you can find tantalum resistors on the net.Building a 211/VT4C is expensive and that's why people buy
the cheap chinese ones and modify them.You can also use Mundorf silver in oil
caps for signal.My friend spent over US $7000 for his pushpull with phase splitter transformer and that's his cost imagine if you sell this commercially.
I can also build it cheaply but don't expect the sound to send you to heaven.Coming back to suitable driver tube as I said what tube has enough gain and low impedance to get good performance other than using transformer coupling? You can try ecc99 or 6cg7 but they are high impedance.
Still a 2A3 or 300B is much more elegant and look good on the chasis.There is the extreme Sakuma way of 211 vs 211. So are you using AC heater for 211? Keep us posted on your progress. Singa.
Last edited:
Hi asterkoa,
Seems like you are an experienced diyer so you know what you want.I don't have link for the Ongaku schematic but is easy to find because
it is commonly refered to by diyer but not practical to build because you can't
get silver wired output transformers
Building a 211/VT4C is expensive and that's why people buy
the cheap chinese ones and modify them.You can also use Mundorf silver in oil
caps for signal.My friend spent over US $7000 for his pushpull with phase splitter transformer and that's his cost imagine if you sell this commercially.
Coming back to suitable driver tube as I said what tube has enough gain and low impedance to get good performance other than using transformer coupling? You can try ecc99 or 6cg7 but they are high impedance.
Hi Singa:
Thanks for your suggestion.
I use Mundorf silver in oil (0.33uf/1200V) already.
Your are right I also use ACheater for 211 and 6c45pi is AC
heater too.
AsterKao
Mr211's Blog - Yahoo!?????--
Hi!
the 417A is also not a good driver for such an output tube. My critique is not based on the gain but on the lack of headroom. Your driver tube will dominate the sound of the amp because of this, the result will be far from the potential a 211 has.
It is not a godd idea to squeeze as much out of two stages as possible. Sometimes it is better to spend an extra stage.
With RC coupling you won't get the full gain from the 6C45 anyways.
An excellent driver and much overlooked tube would be the 6AH4 for example. Then of course you'd need another stage for adequate gain.
I agree with other comments that it is expensive to build a good 211 amp. If the budget is not available I'd rather built with other tubes than having a compsomised 211 amp which will actuall sound like a 6C45 amp.
That is all just my opinion of course
Thomas
the 417A is also not a good driver for such an output tube. My critique is not based on the gain but on the lack of headroom. Your driver tube will dominate the sound of the amp because of this, the result will be far from the potential a 211 has.
It is not a godd idea to squeeze as much out of two stages as possible. Sometimes it is better to spend an extra stage.
With RC coupling you won't get the full gain from the 6C45 anyways.
An excellent driver and much overlooked tube would be the 6AH4 for example. Then of course you'd need another stage for adequate gain.
I agree with other comments that it is expensive to build a good 211 amp. If the budget is not available I'd rather built with other tubes than having a compsomised 211 amp which will actuall sound like a 6C45 amp.
That is all just my opinion of course
Thomas
Hi!
While the 2A3 and 300B are much better choices than the 6C45, I don't think they complement the 211 well. I'd go for a 801A driver. I have built that and it sounds excellent. I've also built a 211/211 amp and that is yet better!
But a DHT driver will drive the cost up a lot. DC filaments are necessary with DHT drivers and I would also use DC on the 211.
A DHT driver will either require a thirs stage for gain or a step up input transformer which in turn needs an adequate preamp which can dirver it. But I agree with you a 211 will be expensive if done right.
Thomas
2A3 or 300B is much more elegant and look good on the chasis.There is the extreme Sakuma way of 211 vs 211.
While the 2A3 and 300B are much better choices than the 6C45, I don't think they complement the 211 well. I'd go for a 801A driver. I have built that and it sounds excellent. I've also built a 211/211 amp and that is yet better!
But a DHT driver will drive the cost up a lot. DC filaments are necessary with DHT drivers and I would also use DC on the 211.
A DHT driver will either require a thirs stage for gain or a step up input transformer which in turn needs an adequate preamp which can dirver it. But I agree with you a 211 will be expensive if done right.
Thomas
Hi Thomas:
Got it your opinion is very useful.
Indeed budget is a concern and case size is a concern too.
But I still will check 6AH4 spec.
Aster
Mr211's Blog - Yahoo!?????
Toy11 VT4C 211AMP -2
After estimate placement too many components so I decide to build mono mono amp.
Drill holes for mount components.
Rectifier tub is 5U4G.
Signal driveing tub 6C45pi.
Amp tub VT4c-211.
High voltage for 211 plate voltage I usage C-L-C balance circuit .
Two chocks one is for 211 B+ another for GND.
Mr211's Blog - Yahoo!?????
After estimate placement too many components so I decide to build mono mono amp.
Drill holes for mount components.
Rectifier tub is 5U4G.
Signal driveing tub 6C45pi.
Amp tub VT4c-211.
High voltage for 211 plate voltage I usage C-L-C balance circuit .
Two chocks one is for 211 B+ another for GND.
Mr211's Blog - Yahoo!?????
Hi Thomas:
After check ...6AH4 spec.
6AH4 Plate resistance 1780ohm, Amplifier factor (gain factor) only 8 @240V ,Transconductance 4500 seem need one more satge then The gain that's enough to drivering 211. that's right?
Mr211's Blog
Mr211's Blog - Yahoo!?????
Hi!
Yes that's right, as I wrote already. In some cases it is better to split the task into two stages: Leave the gain to an input stage and the driving to another.
BTW it should be run at much higher voltage than 240 to obtain more headroom.
Thomas
Yes that's right, as I wrote already. In some cases it is better to split the task into two stages: Leave the gain to an input stage and the driving to another.
BTW it should be run at much higher voltage than 240 to obtain more headroom.
Thomas
Hi Thomas,
It is indeed rare to encounter someone who has tried
Sakuma's method of using same output as driver ie. 211 vs 211(cost factor) although you use DC heaters.I like to hear your take or personal impression of
the sound quality versus other standard implementation of single ended amps (Other people who visited Sakuma's little cafe in Japan said the sound was no big deal.).Yes the japanese seem to like 801 tube too but as output ,what is the reason or rationale for your choice as driver? Thanks.
Singa
Hi Singa!
With my method of DC supply, LCL with no cap across the filament, the DC will have no negative impact on the sound. In contrary, taking hum aside, I prefer the sound of a well implemented DC filament for the 211. It is costly and heavy though.
While my concepts are heavily inspired by Sakuma, my goal is to achieve a good bandwidth and very high resolution and transparency with my amps.
The 211/211 amp is soundwise the best amp I have built so far (and I have built many). It uses independent 3-phase power supplies for each stage and filaments.
On my blog I already wrote about headroom and op points. These articles should make the choice for driver tubes like 801A clear. Besides this, I like the sound qualities of thoriated tungsten filament triodes. I fact the 801A is my favorite tube which I also use as output and line stage tube.
I have also built 801A power amps with 801A driver.
But such tubes will only sound good if done right, especially the filament supply. I'd rather choose other tubes if the budget is not suffiecient. On my blog I'm also presenting lower cost alternatives which will provide excellent sound quality at given cost points.
Best regards
Thomas
With my method of DC supply, LCL with no cap across the filament, the DC will have no negative impact on the sound. In contrary, taking hum aside, I prefer the sound of a well implemented DC filament for the 211. It is costly and heavy though.
While my concepts are heavily inspired by Sakuma, my goal is to achieve a good bandwidth and very high resolution and transparency with my amps.
The 211/211 amp is soundwise the best amp I have built so far (and I have built many). It uses independent 3-phase power supplies for each stage and filaments.
Yes the japanese seem to like 801 tube too but as output ,what is the reason or rationale for your choice as driver? Thanks.
On my blog I already wrote about headroom and op points. These articles should make the choice for driver tubes like 801A clear. Besides this, I like the sound qualities of thoriated tungsten filament triodes. I fact the 801A is my favorite tube which I also use as output and line stage tube.
I have also built 801A power amps with 801A driver.
But such tubes will only sound good if done right, especially the filament supply. I'd rather choose other tubes if the budget is not suffiecient. On my blog I'm also presenting lower cost alternatives which will provide excellent sound quality at given cost points.
Best regards
Thomas
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