Hi Jeff,
Thanks very much for your post.
Regarding Transformers, These are already ordered.Will the performance really be hampered significantly? Hopefully not too bad.
Re - Enclosures: I have ordered 10mm thick aluminium front panel variant Galaxy chassis from Modushop. They were not a bad price at £75 delivered for the 2 units, so i am happy there.
If there is a major issue with the Output trafos I might put them up for sale to help finance some 5k ones.
Regards,
Peter.
Jeff,
Managed to cancel my Trafoe order and am attempting to source from Edcor. Having problems though!
BTW - I have re-checked the schematics and they confirm that the output transformer is 8k. Did you ever find out what rating your's were?
Pete.
Pete,
I am so sorry, I am totally losing it. I confused this thread with the KT88SE thread I am also subscribed to. I built these as well using Edcor, the designer's choice, and am entirely pleased with these too. Forgive me for butting in and being wrong....you are absolutely correct on the 8k.
What seems to be the problem with Edocr, the new webstore? Used to be you sent them a message or email with what you want and they send an invoice to pay. I have not used the new web store but if you use the message tool on the "contact us" tab of their site and send a message to Phyllis she will certainly give you a hand.
Keep in mind, the Edcor has only one secondary value so if you really need a multiple secondary OPT to run 4 or 16 ohm speakers as well you will need another brand or ask them to custom wind a multi tap output for you for and addition fee. Maybe they wouldn't charge the design fee for this and it would only be a little more, you'll just have to ask.
You could also ask for a single 6 ohm to run either a 4 or 8 ohm with little performance tradeoff.
Edcor has about a six week build time so be prepared for that too.
Also, it will take more space but I would seriously consider using oil filled motor run caps for you power supply. They can be purchased very reasonably at Burden Surplus online. I think they have an 80uf cap value you could parallel to a smaller 20uf film for the 100uf caps and use a 50 uf in place of the 47's. This is of course if you have the real estate up top to do it. I also subbed a 5H choke for the resistor between the two 100's.
Diyaudioprojects.com has the part numbers for both the output and power transformers from Edcor. I think you will spend about 100 pounds for all three before shipping, that leaves quite a lot in your budget for some premium parts.
I went with the Russian PIO caps at first but switched to some copper foils from Angela's webstore. I also used all PRP resistors. It is a really great amp, you will be well pleased if you take your time and build it right.
Good luck, let me know if you need any other help. Sorry again about the confusion, I hope you didn't cancel your trafos due to that.
One last thing, I found I preferred using the lower powered RCA 6L6GC, really sounds nice on this amp.
Sincerely,
Jeff
I am so sorry, I am totally losing it. I confused this thread with the KT88SE thread I am also subscribed to. I built these as well using Edcor, the designer's choice, and am entirely pleased with these too. Forgive me for butting in and being wrong....you are absolutely correct on the 8k.
What seems to be the problem with Edocr, the new webstore? Used to be you sent them a message or email with what you want and they send an invoice to pay. I have not used the new web store but if you use the message tool on the "contact us" tab of their site and send a message to Phyllis she will certainly give you a hand.
Keep in mind, the Edcor has only one secondary value so if you really need a multiple secondary OPT to run 4 or 16 ohm speakers as well you will need another brand or ask them to custom wind a multi tap output for you for and addition fee. Maybe they wouldn't charge the design fee for this and it would only be a little more, you'll just have to ask.
You could also ask for a single 6 ohm to run either a 4 or 8 ohm with little performance tradeoff.
Edcor has about a six week build time so be prepared for that too.
Also, it will take more space but I would seriously consider using oil filled motor run caps for you power supply. They can be purchased very reasonably at Burden Surplus online. I think they have an 80uf cap value you could parallel to a smaller 20uf film for the 100uf caps and use a 50 uf in place of the 47's. This is of course if you have the real estate up top to do it. I also subbed a 5H choke for the resistor between the two 100's.
Diyaudioprojects.com has the part numbers for both the output and power transformers from Edcor. I think you will spend about 100 pounds for all three before shipping, that leaves quite a lot in your budget for some premium parts.
I went with the Russian PIO caps at first but switched to some copper foils from Angela's webstore. I also used all PRP resistors. It is a really great amp, you will be well pleased if you take your time and build it right.
Good luck, let me know if you need any other help. Sorry again about the confusion, I hope you didn't cancel your trafos due to that.
One last thing, I found I preferred using the lower powered RCA 6L6GC, really sounds nice on this amp.
Sincerely,
Jeff
Thanks for all the info Jeff.
Really glad i found this forum. Excellent advice and generosity. Cool people on here.
Getting quite excited for the moment when we can get cracking. Most of the other components have arrived (with corporate discount - 'thanks Siemens') From RS Components.
My Galaxy Enclosures have arrived
Realy pleased with these. 103 euros delivered for the 2. 10mm Aluminium front panel. Very well designed, nicely finished. Definately a good buy.
See attachments - I think its on here. My laptop is playing up!
Really glad i found this forum. Excellent advice and generosity. Cool people on here.
Getting quite excited for the moment when we can get cracking. Most of the other components have arrived (with corporate discount - 'thanks Siemens')
From RS Components. My Galaxy Enclosures have arrived
Realy pleased with these. 103 euros delivered for the 2. 10mm Aluminium front panel. Very well designed, nicely finished. Definately a good buy.
See attachments - I think its on here. My laptop is playing up!
Attachments
Last edited:
500v Electrolytics
Had a nightmare with these!
But..... Incase anyone else is looking for an alternative in the UK
Right buggers to source, can't find anywhere in the UK. No wonder the country is going down the tubes. The only ones were the Panasonic 500v which are no longer available, now replaced by 450v which is too dodgy.
However - Cue ze Germans and their efficient manufacturing capabilities!
High quality 50u + 50u long life. So 3 units per amp - 2 for the 100u caps by paralleling the twin 50u tags and 1 for the 2 x 50u caps. Perfekt!
View at Mundorf M-Lytic HV, Audio Capacitor 50uf + 50uF 500V on eBay (end time 28-Nov-10 22:11:57 GMT)
Had a nightmare with these!
But..... Incase anyone else is looking for an alternative in the UK
Right buggers to source, can't find anywhere in the UK. No wonder the country is going down the tubes. The only ones were the Panasonic 500v which are no longer available, now replaced by 450v which is too dodgy.
However - Cue ze Germans and their efficient manufacturing capabilities!
High quality 50u + 50u long life. So 3 units per amp - 2 for the 100u caps by paralleling the twin 50u tags and 1 for the 2 x 50u caps. Perfekt!
View at Mundorf M-Lytic HV, Audio Capacitor 50uf + 50uF 500V on eBay (end time 28-Nov-10 22:11:57 GMT)
Trafoes Despatched!! Question About KT88 Matching
Hi guys.
As stated in the title of this post, Edcor have shipped my Trafoes
I have a question regarding matching on KT88 tubes though. As I am building 2 x monoblocks what is the best way to buy the output tubes? I am going for GE Golden Lions as they are on offer at Watford Valves atm. However, when purchasing i need to specify whether i'd prefer matched in pairs or in quads? Would matched Quads be the way forward to keep uniformity across both blocks?
Thanks in advance.
Peter.
Hi guys.
As stated in the title of this post, Edcor have shipped my Trafoes
I have a question regarding matching on KT88 tubes though. As I am building 2 x monoblocks what is the best way to buy the output tubes? I am going for GE Golden Lions as they are on offer at Watford Valves atm. However, when purchasing i need to specify whether i'd prefer matched in pairs or in quads? Would matched Quads be the way forward to keep uniformity across both blocks?
Thanks in advance.
Peter.
Wow!!!!
Well,
After many long hours of investigation and also some nervous moments performing low voltage then H.V tests on the blocks I am pleased to say that my build is done.
I decided on substituting the thermal valve relay with a classic OP-Amp circuit incorporating a 500V rated relay.
I have attached a link to a picture of the finished units below.
ImageShack® - Online Photo and Video Hosting
I am delighted with them. My father and I thoroughly enjoyed the experience (despite the worries on initial power up!!)
Just wanted to thank everyone on here who helped me in the initial stages.
The Oddblock Mono's are a great design and sound sublime.
Peter.
Well,
After many long hours of investigation and also some nervous moments performing low voltage then H.V tests on the blocks I am pleased to say that my build is done.
I decided on substituting the thermal valve relay with a classic OP-Amp circuit incorporating a 500V rated relay.
I have attached a link to a picture of the finished units below.
ImageShack® - Online Photo and Video Hosting
I am delighted with them. My father and I thoroughly enjoyed the experience (despite the worries on initial power up!!)
Just wanted to thank everyone on here who helped me in the initial stages.
The Oddblock Mono's are a great design and sound sublime.
Peter.
Poddwatt Class A stereo Amplifier: help
I am building an Poddwatt Class A stereo Amplifier(Oddwatt S2 stereo Amplifier)5751SRPP /EL84 Tube Amp, and am following the drawing by Mr.Bruce Heran..
I need the following clarifications:
1)Can the Solen 1.0UF capacitor in the power supply circuit be Electrolytic or should it be Bipolar cap?
2)The capacitor marked 'C' connected between output transformer center tap and ground, can it be be electrolytic or should it be bipolar cap.
3) What should the bias current be ideally?
lastly can anyone give me the ckt of the line filter?
Thanks,
EFu1944
I am building an Poddwatt Class A stereo Amplifier(Oddwatt S2 stereo Amplifier)5751SRPP /EL84 Tube Amp, and am following the drawing by Mr.Bruce Heran..
I need the following clarifications:
1)Can the Solen 1.0UF capacitor in the power supply circuit be Electrolytic or should it be Bipolar cap?
2)The capacitor marked 'C' connected between output transformer center tap and ground, can it be be electrolytic or should it be bipolar cap.
3) What should the bias current be ideally?
lastly can anyone give me the ckt of the line filter?
Thanks,
EFu1944
Bruce,
I am new to tubes though I have bult the 12AX7 Preamp and the 4S universal preamp with very good results. I am now attempting to build your design of the Oddwatt S2 Amp using the 5751/ EL84 combination.
I would like to know if PCB pattern design could be available for the amp and Power supply boards, since I would like to use PCBs instead of point to point wiring.
Sharat
I am new to tubes though I have bult the 12AX7 Preamp and the 4S universal preamp with very good results. I am now attempting to build your design of the Oddwatt S2 Amp using the 5751/ EL84 combination.
I would like to know if PCB pattern design could be available for the amp and Power supply boards, since I would like to use PCBs instead of point to point wiring.
Sharat
Oops
Hi, Sorry I have been non-responsive. My vintage mind forgot there was a thread here. Since the notification came through OK, I should be able to answer stuff on the thread. BTW, I usually will not cross reference sites, but there is extensive information in several threads on the diyaudioprojects.com site (100's of pages there). To answer the two recent questions, no there is no pcb for the amplifiers. The only ones available (I am not pushing a comercial issue here as it is against my principles) are the ones in the commercial kits. If you want to go that way then you can google the kits. Same for the list of components. I do accept and answer emails. You can PM me on this site or reach me at support@oddwattaudio.com. I enjoy many of the questions and will attempt to give unbiased answers to them.
Hi, Sorry I have been non-responsive. My vintage mind forgot there was a thread here. Since the notification came through OK, I should be able to answer stuff on the thread. BTW, I usually will not cross reference sites, but there is extensive information in several threads on the diyaudioprojects.com site (100's of pages there). To answer the two recent questions, no there is no pcb for the amplifiers. The only ones available (I am not pushing a comercial issue here as it is against my principles) are the ones in the commercial kits. If you want to go that way then you can google the kits. Same for the list of components. I do accept and answer emails. You can PM me on this site or reach me at support@oddwattaudio.com. I enjoy many of the questions and will attempt to give unbiased answers to them.
I'm new to the forum and I'm in the process of collecting parts for an oddwatt kt120 build. I'm considering building a single chassis stereo unit and I'm looking to see if it would be possible to utilize a toroidal power transformer. Would the Antek As-4t360 be a suitable choice? 360v .55a, 360v .55a, 6.3 4a x2.
Btw, my first post and thank you all for sharing your knowledge...
John
Btw, my first post and thank you all for sharing your knowledge...
John
Hi Bruce,
A quick public note of thanks for a great sounding Poddwatt amp. Anyone considering this option can rest assured that the instructions are COMPREHENSIVE! and dealing with you and Rodney has been a pleasure. I didn't bother including any pictures as mine came out looking just like the ones on your website.
My daughter is looking at a headphone amp... Alpha?
cheers
Beardy (aka Mike W)
A quick public note of thanks for a great sounding Poddwatt amp. Anyone considering this option can rest assured that the instructions are COMPREHENSIVE! and dealing with you and Rodney has been a pleasure. I didn't bother including any pictures as mine came out looking just like the ones on your website.
My daughter is looking at a headphone amp... Alpha?
cheers
Beardy (aka Mike W)
Hi there,
I finally completed two Poddwatt stereo amps( one with a regulated supply for the driver tube), and am totally impressed by their performance.Both are the El 84 push pulls. Bruce has been as usual very helpful in clearing all my doubts and giving valuable suggestions, and I thank profusely him.
I was able to design and etch the PCBs for both the Poddwatts and power supplies .from the schematics, and they have come out pretty well . Anyone interested in the pattern drawing please mail me at sharatdesh@yahoo.com.
Sharat
I finally completed two Poddwatt stereo amps( one with a regulated supply for the driver tube), and am totally impressed by their performance.Both are the El 84 push pulls. Bruce has been as usual very helpful in clearing all my doubts and giving valuable suggestions, and I thank profusely him.
I was able to design and etch the PCBs for both the Poddwatts and power supplies .from the schematics, and they have come out pretty well . Anyone interested in the pattern drawing please mail me at sharatdesh@yahoo.com.
Sharat
Hi all, I'm in the process of building a pair of oddblocks, and I've met with a limitation of knowledge referring to resistor voltages. In the amplifier circuit, what voltage do the resistors need to be rated for?
I've bought Ohmite Audio Gold resistors for the whole circuit, though I've had to purchase the 10w versions to remain in line with the assumed 500v circuit voltage. Problem there of course is the physical size of a whole circuit full of 10w resistors, and the fact that when you start looking for good/best/favoured quality resistors, you are somewhat limited in the 500v+ range. I'd really like to use Caddock 132's or AN Silver Tants, though I simply can't reach the voltage requirements. Am I missing something here, is this voltage all of that important given the currents we are working with?
Thanks in advance
Ox
I've bought Ohmite Audio Gold resistors for the whole circuit, though I've had to purchase the 10w versions to remain in line with the assumed 500v circuit voltage. Problem there of course is the physical size of a whole circuit full of 10w resistors, and the fact that when you start looking for good/best/favoured quality resistors, you are somewhat limited in the 500v+ range. I'd really like to use Caddock 132's or AN Silver Tants, though I simply can't reach the voltage requirements. Am I missing something here, is this voltage all of that important given the currents we are working with?
Thanks in advance
Ox