Corbato's amp from the tube amp gallery -
http://www.diyaudio.com/forums/showthread.php?postid=973028#post973028
http://www.diyaudio.com/forums/showthread.php?postid=973028#post973028
Met Viren Bakshi, since it was a late evening meeting, I really didn't have the energy to discuss much, mostly listed to some nice music.(see lyritaaudio,com) He did say that Delta was a good bet for power and output transformers, so it may be good to consider some reverse engineering, if the plan is to start from basics. The power tranny should be relatively easy to do, but the output transformers, may require a unit to be got from the US and then cloned.
My first tube amp - VTA driver board, my own power supply/soft start board.
SS rectified, JJ 12AT7 driver tubes and JJ KT77 power tubes. UL/Triode switchable.
Transformers are all toroid, from Trafomatic.
Chassis is 1.6mm steel, designed by me, and made here in Hyderabad.
It hums a bit. I need to clean up the wiring and also the
el cheapo selector switch I used is noisy.
But otherwise, it sounds really sweet.
Pics here -
http://picasaweb.google.com/prasadb/TubeAmp
- Prasad
SS rectified, JJ 12AT7 driver tubes and JJ KT77 power tubes. UL/Triode switchable.
Transformers are all toroid, from Trafomatic.
Chassis is 1.6mm steel, designed by me, and made here in Hyderabad.
It hums a bit. I need to clean up the wiring and also the
el cheapo selector switch I used is noisy.
But otherwise, it sounds really sweet.
Pics here -
http://picasaweb.google.com/prasadb/TubeAmp
- Prasad
You can buy new (made in China) 813 tubes on Lamington Road. (Rs 2400 each).
Apparently they are used in the plastics industry for induction heating.
Does anyone know of any other tubes that can be reliably purchased in India ?
(i.e. regular supply, not 2 pieces lying in someone's godown for the last 30 years).
Apparently they are used in the plastics industry for induction heating.
Does anyone know of any other tubes that can be reliably purchased in India ?
(i.e. regular supply, not 2 pieces lying in someone's godown for the last 30 years).
Hi All
Just stumbled upon your post. Wow what a relief, thought I was on a deserted island over here. I have build a few speakers in the past including a back loaded horn speaker and tpqw speakers.
I just completed prototyping a 5842se amp, this is my first tube project. Did not get much volume, however the sound was amazing, my wife said that the now she hears the voice and music separately
.
I also had some 6as7 tube with me, so i converted my 582se amp to para feed using its existing transformer as a choke and build as 6as7se amp. The volume is lound enough that I have to shout to speak. This volume is good enough for me. Still miss the bass of my SS amp.
By the way i now listen in mono, My speakers are OB type based on Lukasz Fikus design of Lampizator. It consist of 2 x 15" upto 200hz, 2 x 5" for the mids upto 5000hz and 2 conical tweeters for the highs. I also owe it to JELABS whose one email got me to think Open baffles.
By the way NO HUM
From my experience the most difficult part to get is a Quality output transformer over here. And from what i have read it seem that the final out come depends on that lump of iron. I have contacted Salzer in this regard, they have technical collaboration with Piltron and they can manufacture toroidal outputs as well as LCL and CLC chokes as per Piltrons specs. However they are a bit costly and i think they require at least 10 nos made at a time. May be this helps.
My next project. Lets see 5842 - 6as7/6pi3p/45 - 845/813se (operating at low voltage for 4 watts - i am a new bee). Now only if I can locate those 845's.
Fantastic effort guys I know how difficult it is to do what you guys have started.
Regards
Avinash Alves
Just stumbled upon your post. Wow what a relief, thought I was on a deserted island over here. I have build a few speakers in the past including a back loaded horn speaker and tpqw speakers.
I just completed prototyping a 5842se amp, this is my first tube project. Did not get much volume, however the sound was amazing, my wife said that the now she hears the voice and music separately
.I also had some 6as7 tube with me, so i converted my 582se amp to para feed using its existing transformer as a choke and build as 6as7se amp. The volume is lound enough that I have to shout to speak. This volume is good enough for me. Still miss the bass of my SS amp.
By the way i now listen in mono, My speakers are OB type based on Lukasz Fikus design of Lampizator. It consist of 2 x 15" upto 200hz, 2 x 5" for the mids upto 5000hz and 2 conical tweeters for the highs. I also owe it to JELABS whose one email got me to think Open baffles.
By the way NO HUM
From my experience the most difficult part to get is a Quality output transformer over here. And from what i have read it seem that the final out come depends on that lump of iron. I have contacted Salzer in this regard, they have technical collaboration with Piltron and they can manufacture toroidal outputs as well as LCL and CLC chokes as per Piltrons specs. However they are a bit costly and i think they require at least 10 nos made at a time. May be this helps.
My next project. Lets see 5842 - 6as7/6pi3p/45 - 845/813se (operating at low voltage for 4 watts - i am a new bee). Now only if I can locate those 845's.
Fantastic effort guys I know how difficult it is to do what you guys have started.
Regards
Avinash Alves
Re: Parts in India
I would suggest EL84 PP (about 12-15W) since these tubes are available maybe even the baby Huey.
You could go Parallel Push Pull with EL84 to get 25-30W rms but...PPP has it's own problems.
If you guys are importing JJ EL34's for about $1 more get the BL versions (the glass is tinted blue).
Virenji, why not use a SS rectifier and CCS?
Virenji, Can you help us with Delta?
BELs are available in Mumbai too just that supplies are sporadic.
sagar said:
I would suggest EL84 PP (about 12-15W) since these tubes are available maybe even the baby Huey.
virenb said:
You could go Parallel Push Pull with EL84 to get 25-30W rms but...PPP has it's own problems.
If you guys are importing JJ EL34's for about $1 more get the BL versions (the glass is tinted blue).
Virenji, why not use a SS rectifier and CCS?
Virenji, Can you help us with Delta?
gjo said:
BELs are available in Mumbai too just that supplies are sporadic.
Interesting post.avisa said:
You stay at Dahanu? Can I come and visit sometime when it's convenient to you and listen to your systems? I need to visit Vapi/Bhilad/Daman once every few months because one large client has factories there. I may be able to drop in at Dahanu during one of those trips.
BTW, Delta Transformer of Delhi makes really good output transformers, I'm told. One very good-valve-amp maker gets his stuff from them. The key people at Delta admit that some of the really high-end core material used by some makes like Lundahl are not available to Delta, but barring this shortcoming, they still make output transformers which perform really well. And given the fact that they're willing to entertain retail orders, I think it's a great opportunity for you tube guys.
I get R-core power transformers for my (SS) amps from them.
Avinash,
I've been sitting and racking my brain for the last 15 minutes but I can't recall the name.
I threw away his visiting card a few months back.
The shop is on the same side of the road as the police station.
Its on the corner of the lane that leads to Grant Road station.
The name starts with P. Its not Precious, or Peerless or Pioneer or anything I could think of.
If I remember the name I'll post it.
Otherwise you'll have to do a bit of detective work yourself.
On my next trip to Bombay I'll stop by his shop and get his card.
I've been sitting and racking my brain for the last 15 minutes but I can't recall the name.
I threw away his visiting card a few months back.
The shop is on the same side of the road as the police station.
Its on the corner of the lane that leads to Grant Road station.
The name starts with P. Its not Precious, or Peerless or Pioneer or anything I could think of.
If I remember the name I'll post it.
Otherwise you'll have to do a bit of detective work yourself.
On my next trip to Bombay I'll stop by his shop and get his card.
Re: Re: regarding 813 valves
I think we can get by using SS for the rectifier and CCS. THis will reduce our valve burden. I'm told that there is a OPT manufacturer in the South who makes "Torroidal OPTs". I did not get a name but when I do i'll post it.
Meanwhile if Delta is still operational it is good bet. I was gifted two used Delta OPTs some time back and atleast one of them is good (I have not used the other one yet).
Well we'll need a power tranny as well so maybe we can use R-core for the power tranny. How are their prices compared to Miracle etc.
I dont think Valvetronics stock the 813. I thik he mostly stock small signal stuff and none of it packed. Just a bin of loose tubes.
Chunam Lane? Is it at the end of the lane in the chawl style building on the left?
Precious used to stock valves when I was active in Audio (late 70s early 80s) I dont think they do now. Then again I have not visited the area since about '94.
gjo said:
I think we can get by using SS for the rectifier and CCS. THis will reduce our valve burden. I'm told that there is a OPT manufacturer in the South who makes "Torroidal OPTs". I did not get a name but when I do i'll post it.
Meanwhile if Delta is still operational it is good bet. I was gifted two used Delta OPTs some time back and atleast one of them is good (I have not used the other one yet).
tcpip said:
Well we'll need a power tranny as well so maybe we can use R-core for the power tranny. How are their prices compared to Miracle etc.
tcpip said:
I dont think Valvetronics stock the 813. I thik he mostly stock small signal stuff and none of it packed. Just a bin of loose tubes.
pjp said:
Chunam Lane? Is it at the end of the lane in the chawl style building on the left?
Precious used to stock valves when I was active in Audio (late 70s early 80s) I dont think they do now. Then again I have not visited the area since about '94.
Hi all!
Well TCPIP sure, come over, my weekly off are Friday & Saturday, just give me a call in advance - Cell # 9975407209, Would appreciate your comments and love to improve.
PJP, Navinbhai I know what you mean about availability of valves, I purchased the valves I have 10 years back. At that time I did not realise how dificult it would become to get valves now.
I use to see the guys from Hong Kong, Taiwan buying large quantity of good Nos VT4C's, 845's, 833's, 45's 2A3, 6B4, WE417's... 212e, NOS. Paper in Oil Caps, wow I just hope I had bought some then.
Navinbhai the manufacturer of the Toroidal output Transformer in south is Salzer, Contact Person Mr. Prabhu S Sr. Engg Mfg Phone no: 04254 - 272311 Web: salzergroup.com. (They say they can build the OPT with the same quality as piltron who are their colaborators) Hope it helps.
Regards
Avinash
Well TCPIP sure, come over, my weekly off are Friday & Saturday, just give me a call in advance - Cell # 9975407209, Would appreciate your comments and love to improve.
PJP, Navinbhai I know what you mean about availability of valves, I purchased the valves I have 10 years back. At that time I did not realise how dificult it would become to get valves now.
I use to see the guys from Hong Kong, Taiwan buying large quantity of good Nos VT4C's, 845's, 833's, 45's 2A3, 6B4, WE417's... 212e, NOS. Paper in Oil Caps, wow I just hope I had bought some then.
Navinbhai the manufacturer of the Toroidal output Transformer in south is Salzer, Contact Person Mr. Prabhu S Sr. Engg Mfg Phone no: 04254 - 272311 Web: salzergroup.com. (They say they can build the OPT with the same quality as piltron who are their colaborators) Hope it helps.
Regards
Avinash
Hey guys,
Just wanted to give a heads-up on Miracle transformers. I am making a Marshall 18W tube guitar amplifier( 2x12AX7, 2xEL84 PP 18W). As you know getting the OT and PT in India is a big pain. I managed to get the exact OT specs of the vintage amp's Radio Spares transformer and gave it to Miracle. I also ordered a PT with 120/240V primary and secondaries at 300-0-300 @125mA, 3.15-0-3.15@3.25A, 0-5-6.3@2A,1A. Both are E-I core and were ordered in single piece qty.
The transformers came in today and I must say they look and feel pretty solid. They were extremely well packed. These guys are very prompt and professional. I had a lot of correspondence and they replied immediately every time. The PT cost me Rs 1250/- and OT Rs 1000/-, overall Rs. 3051/- with taxes. It will be quite some time before I make the amp(caught up with office work) but I will report back on how they perform. BTW, I am tube n00b so my first valve amp will surely sound good to me
If anybody needs valves in Bangalore they can go to Famous Radio Co on SJP Road. Also, Mohammed Ansar at www.be3amplifiers.com stocks all these parts like tubes, sockets, custom Xformers etc. I have interacted with him and he is keen on helping the DIY crowd. Check out his site, he is selling some nice guitar amplifiers for a very fair price.
All in all, tube enthusiasts in India can now think about making amps with local components - a fully desi valve amplifier if you will!
- Venkatesh
Just wanted to give a heads-up on Miracle transformers. I am making a Marshall 18W tube guitar amplifier( 2x12AX7, 2xEL84 PP 18W). As you know getting the OT and PT in India is a big pain. I managed to get the exact OT specs of the vintage amp's Radio Spares transformer and gave it to Miracle. I also ordered a PT with 120/240V primary and secondaries at 300-0-300 @125mA, 3.15-0-3.15@3.25A, 0-5-6.3@2A,1A. Both are E-I core and were ordered in single piece qty.
The transformers came in today and I must say they look and feel pretty solid. They were extremely well packed. These guys are very prompt and professional. I had a lot of correspondence and they replied immediately every time. The PT cost me Rs 1250/- and OT Rs 1000/-, overall Rs. 3051/- with taxes. It will be quite some time before I make the amp(caught up with office work) but I will report back on how they perform. BTW, I am tube n00b so my first valve amp will surely sound good to me
If anybody needs valves in Bangalore they can go to Famous Radio Co on SJP Road. Also, Mohammed Ansar at www.be3amplifiers.com stocks all these parts like tubes, sockets, custom Xformers etc. I have interacted with him and he is keen on helping the DIY crowd. Check out his site, he is selling some nice guitar amplifiers for a very fair price.
All in all, tube enthusiasts in India can now think about making amps with local components - a fully desi valve amplifier if you will!
- Venkatesh
nebucanazza said:
Just wanted to give a heads-up on Miracle transformers. I am making a Marshall 18W tube guitar amplifier( 2x12AX7, 2xEL84 PP 18W). As you know getting the OT and PT in India is a big pain. I managed to get the exact OT specs of the vintage amp's Radio Spares transformer and gave it to Miracle. I also ordered a PT with 120/240V primary and secondaries at 300-0-300 @125mA, 3.15-0-3.15@3.25A, 0-5-6.3@2A,1A. Both are E-I core and were ordered in single piece qty.
The transformers came in today and I must say they look and feel pretty solid. They were extremely well packed. These guys are very prompt and professional. I had a lot of correspondence and they replied immediately every time. The PT cost me Rs 1250/- and OT Rs 1000/-, overall Rs. 3051/- with taxes. It will be quite some time before I make the amp(caught up with office work) but I will report back on how they perform. BTW, I am tube n00b so my first valve amp will surely sound good to me
If anybody needs valves in Bangalore they can go to Famous Radio Co on SJP Road. Also, Mohammed Ansar at www.be3amplifiers.com stocks all these parts like tubes, sockets, custom Xformers etc.
Mama mia! You too?
I too am thinking of building a Marshall 18W combo. The problem I have so far is sourcing the Celestion G12M 20Watt driver. BTW the Marshall schematic (1974x) I got requires 3 ECC83s not 2.
I would love to have the OT/PT specs of your amp. Which schematic are you using?
I have corresponded with Mohammed Ansari in the past I did not know he has grown so much and now stocks tubes and OPTs for DIY.
Well well....another forumite looking for the 18W magic . I am making the LiteIIb, single channel with one volume one tone. Head over to 18watt.com forums for all the info/variations for this circuit.
I researched quite a bit on the forum as well as manufacturer sites and dug out the original specs of the RS OT posted in some old thread at 18watt. Even Mohammed Ansar can send you his 18W custom designed PT and OT, which he made for his amp.
Miracle made it in a week after getting the payment. I don't know how well they'll perform, still a few months away from that. I am attaching the specs as two doc files
. I am making the LiteIIb, single channel with one volume one tone. Head over to 18watt.com forums for all the info/variations for this circuit.I researched quite a bit on the forum as well as manufacturer sites and dug out the original specs of the RS OT posted in some old thread at 18watt. Even Mohammed Ansar can send you his 18W custom designed PT and OT, which he made for his amp.
Miracle made it in a week after getting the payment. I don't know how well they'll perform, still a few months away from that. I am attaching the specs as two doc files
Miracle Electronics, here in Bangalore, is prompt and responsive for one off orders. I ordered a replacement mains transformer earlier this month for my Class A 2A3 Joplin amp(diyhifisupply.com), when the Chinese one packed up, and got it on schedule, installed and am quite happy with the performance.
I drove down to their factory pick it up, and met Nilesh who is the Director handling the unit. I have bought toroidals for my DAC, as well as my AKSA ss amp from him as well as for a subwoofer amp. No complaints at all. He said that he supplied amps to various audio mfrs overseas, to their specs, but since I had limited time, I did not get into a long conversation. He has UL and CE certifications,as well as ISO.
Their website is toroidal.com, I think.
George
I drove down to their factory pick it up, and met Nilesh who is the Director handling the unit. I have bought toroidals for my DAC, as well as my AKSA ss amp from him as well as for a subwoofer amp. No complaints at all. He said that he supplied amps to various audio mfrs overseas, to their specs, but since I had limited time, I did not get into a long conversation. He has UL and CE certifications,as well as ISO.
Their website is toroidal.com, I think.
George
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