I have both EH and TJ full music 300B's. They sound quite differently but I like them both.
Why not have them all. EH 300B is so cheap.
Johnny
Why not have them all. EH 300B is so cheap.
Johnny
Yes! I read this some time ago, but forgot about it.
Excellent! The TJ Meshplate it is!
Why not ask Mrs. Annan? Mrs. Annan is so cheap.
I'm putting together a list of other parts I'm going to order for your collective review.
Stay tuned and thanks again for all the help!
Kofi
Hi Kofi,
I have heard the TJ gold pinned meshplate 300B very recently (not in my amp unfortunately) and thought it sounded very good. I too am curious about this tube and am thinking about acquiring a pair at some point.
The KR labs 300B globe with mesh plates is well regarded and even better reviewed than the TJ, however I have not heard it yet. I plan to acquire a new pair by year's end and will report on them when I do. Other KR's I have used have been great.
Currently I use the JJ300B in both my PP amps and my SE amp - in all cases a very good performer.
In the past I have used Valve Arts 300B and Svetlana 300B neither of which was particularly reliable.
Shuguang solid plate 300B neither sounded good nor was it particularly durable.
I thought the SV300B sounded pretty good until I got my hands on some then current production 300B (about six yrs ago) and the WE just cleaned their clock, as do incidentally the JJ I am currently using. I have not been able to compare the JJ to the WE as I no longer have a pair.
JJ is a good everyday use tube, performs well above most of the pack in my estimation, only the KR or WE are likely to be significantly better. Both are significantly more expensive.
I have heard the TJ gold pinned meshplate 300B very recently (not in my amp unfortunately) and thought it sounded very good. I too am curious about this tube and am thinking about acquiring a pair at some point.
The KR labs 300B globe with mesh plates is well regarded and even better reviewed than the TJ, however I have not heard it yet. I plan to acquire a new pair by year's end and will report on them when I do. Other KR's I have used have been great.
Currently I use the JJ300B in both my PP amps and my SE amp - in all cases a very good performer.
In the past I have used Valve Arts 300B and Svetlana 300B neither of which was particularly reliable.
Shuguang solid plate 300B neither sounded good nor was it particularly durable.
I thought the SV300B sounded pretty good until I got my hands on some then current production 300B (about six yrs ago) and the WE just cleaned their clock, as do incidentally the JJ I am currently using. I have not been able to compare the JJ to the WE as I no longer have a pair.
JJ is a good everyday use tube, performs well above most of the pack in my estimation, only the KR or WE are likely to be significantly better. Both are significantly more expensive.
Another vote for the TJ!
Here's the schematic again, but with some part selections I'm considering. Some questions, as always--
1. How can I get the 60R4 resistor value and what type of resistor should I use here?
2. Would the Kiwame Carbon Films work for the 220Rs? I like them for the precision and I've heard they're nice, but I'd like your opinions.
3. Can I use Mills Wirewounds for the big'uns hanging off the 300b cathode? If so, are there better wirewounds I might consider?
4. Any recommendations on the 100R balance pot?
5. Where the hell do I get off asking such dumb questions?
6. Aren't I ashamed of myself?
7. Aren't I?
I think that Thorsten already responded to my questions concerning the capacitors, but any additional comments on choices here would be appreciated.
Thanks again for all the help,
Kofi
Attachments
Not familiar with this circuit but ...
1. I believe the amp would not complain at all if you make that R 500 or 820 or 470 ... it looks really like a grid stopper and you want to set that value by ear/oscope. At the end of the day, I just removed the grid stoppers.
2. Cheap tyco 700V 2W carbon resistors (my pick-up for screens/bleeder and minor duties)
3. Thick film planar resistor here (OH! I can't remember the brand)
4. Not from me. Anything >0.5W would do the job.
Caps ... I'd go for paper/oil cap for the main ultrapath bypass
Ciao
Gianluca
1. I believe the amp would not complain at all if you make that R 500 or 820 or 470 ... it looks really like a grid stopper and you want to set that value by ear/oscope. At the end of the day, I just removed the grid stoppers.
2. Cheap tyco 700V 2W carbon resistors (my pick-up for screens/bleeder and minor duties)
3. Thick film planar resistor here (OH! I can't remember the brand)
4. Not from me. Anything >0.5W would do the job.
Caps ... I'd go for paper/oil cap for the main ultrapath bypass
Ciao
Gianluca
Hey Kofi, for the 100R pot I used one of these - Precision 100R/3W - 1316849, Wirewound 10R/3W - 1054922. Part numbers from Farnell.
For the 300B, I guess you're the only one who can say what you like. I've heard a OEM China 300B (which I would guess as Valve Art) in my amp (what I own), the TJ baloon mesh (perforated) plate, new production WE300B.
What I can say is that there is audible differences between the 3 of them. Will I spend that much for a WE300B? Maybe if I had the money. I find the TJ a bit slower, mellower than my generic. All three were used in my amp.
For the ultrpath cap, I'd say the Obbligato, but I guess even their "john holmes" is not enough- just 30uF. I don't know if T would agree to just 30uF.
For the 300B, I guess you're the only one who can say what you like. I've heard a OEM China 300B (which I would guess as Valve Art) in my amp (what I own), the TJ baloon mesh (perforated) plate, new production WE300B.
What I can say is that there is audible differences between the 3 of them. Will I spend that much for a WE300B? Maybe if I had the money. I find the TJ a bit slower, mellower than my generic. All three were used in my amp.
For the ultrpath cap, I'd say the Obbligato, but I guess even their "john holmes" is not enough- just 30uF. I don't know if T would agree to just 30uF.
Hi Kofi,
Good to see that you are making progress on your project. I´m also almost ready to start building Thorsten´s phono pre...we´ll be brothers in equipment over the athlantic!
Let´s see. These are the parts that I used on my amps:
47K input resistor: Caddock TF020. I think this resistor is really important for sound quality so the best you can use over here. I guess tantalum would be also good.
60R2: This is the value of the 1st grid stopper resistor that I used on the amp. It was a caddock unit. Good sound but I have later replaced it with a nos 100R 1/8W Bradley. Not a big difference, maybe more of a natural sound with it.
220R: Generic 1/4W metal units. No clue if using "boutique" parts would be of any use here...help anyone?
12W and 9W Resistors: I use Mills wirewound. Maybe I´ll try Caddock Mp-930/925 soon to see if they bring some benefit.
100R pot: Vishay 1280G
100R and 10R next to the pot: Dale 1W
For the WE conections caps I settled with the following combo for it´s sound:
- 50uF and 15uF: Ducati plastic Motor Run
- 3,3uF and 1 uF: Solen MKP
Good to see that you are making progress on your project. I´m also almost ready to start building Thorsten´s phono pre...we´ll be brothers in equipment over the athlantic!
Let´s see. These are the parts that I used on my amps:
47K input resistor: Caddock TF020. I think this resistor is really important for sound quality so the best you can use over here. I guess tantalum would be also good.
60R2: This is the value of the 1st grid stopper resistor that I used on the amp. It was a caddock unit. Good sound but I have later replaced it with a nos 100R 1/8W Bradley. Not a big difference, maybe more of a natural sound with it.
220R: Generic 1/4W metal units. No clue if using "boutique" parts would be of any use here...help anyone?
12W and 9W Resistors: I use Mills wirewound. Maybe I´ll try Caddock Mp-930/925 soon to see if they bring some benefit.
100R pot: Vishay 1280G
100R and 10R next to the pot: Dale 1W
For the WE conections caps I settled with the following combo for it´s sound:
- 50uF and 15uF: Ducati plastic Motor Run
- 3,3uF and 1 uF: Solen MKP
Let´s continue:
220nF and 68nF: Multicap RTX
15nF and 4,7nF: 500V Silver Mica
Hope that this helps a little bit. By the way, the Silver mica caps made a big difference in clarity. Make sure you use those.
I have only used TJ punched plater. Haven´t compared it to any other 300B BUT I have heard very good things on the Emission Labs and KR. No complaints on the TJ so far though.
Keep us posted please. What speakers are you going to be using with these amps?
Best regards,
Luis
220nF and 68nF: Multicap RTX
15nF and 4,7nF: 500V Silver Mica
Hope that this helps a little bit. By the way, the Silver mica caps made a big difference in clarity. Make sure you use those.
I have only used TJ punched plater. Haven´t compared it to any other 300B BUT I have heard very good things on the Emission Labs and KR. No complaints on the TJ so far though.
Keep us posted please. What speakers are you going to be using with these amps?
Best regards,
Luis
Sorry for the delayed response...
Cool. Good to know there's some play in the gridstoppers. I think that the gridstoppers are to prevent the grid from drawing current (right?), but I'm curious to know why you might have more play in this resistor's value over the 47K input job.
I'm NOT challenging this here-- I am really stupid enough to not know.
Good to know. I don't mind trying a few, so it's good to know that price is not necessarily a factor.
Bought a couple of transformers off a barnacle in Las Vegas and some aluminum. Wheee.
Jack's the greatest, really. But if you've talked to him, you know what I'm talkin' 'bout!
Well, I like the Caddock idea. They look like the sort of resistors you'd see in The Matrix.
I like those fine.
Got some Fostex 206Es in a backhorn. I like them a lot, but I need to re-box in an ML-TL.
I need to add photos of the huge transformers Jack wound for me. If these got into the wrong hands...
Kofi
Cool. Good to know there's some play in the gridstoppers. I think that the gridstoppers are to prevent the grid from drawing current (right?), but I'm curious to know why you might have more play in this resistor's value over the 47K input job.
I'm NOT challenging this here-- I am really stupid enough to not know.
Good to know. I don't mind trying a few, so it's good to know that price is not necessarily a factor.
Bought a couple of transformers off a barnacle in Las Vegas and some aluminum. Wheee.
Jack's the greatest, really. But if you've talked to him, you know what I'm talkin' 'bout!
Well, I like the Caddock idea. They look like the sort of resistors you'd see in The Matrix.
I like those fine.
Got some Fostex 206Es in a backhorn. I like them a lot, but I need to re-box in an ML-TL.
I need to add photos of the huge transformers Jack wound for me. If these got into the wrong hands...
Kofi
Hello all. For the Thorsten 300B. Is there an original thread or link on the web that provides more information on it?
Thanks in advance.
Thanks in advance.
Forget my previous post. I found the Thunderstone version of the Opera M500 modification with the 437A input driver.
The D3A 300B DRD is a simpler circuit then the Opera modification. With some changes the 437A can be used instead of the D3A?
Why use the D3A pentode in triode mode instead of the original 437A triode?
Thanks in advance.
The D3A 300B DRD is a simpler circuit then the Opera modification. With some changes the 437A can be used instead of the D3A?
Why use the D3A pentode in triode mode instead of the original 437A triode?
Thanks in advance.
Hi,
You bet. You can also use triodes like the EC8010, EC8020, 6C45P...and triode connected pentodes as the E280F, E180F...and others.
Because the D3a is a much, much cheaper tube (at least for now) and also cos´ wired like a triode this pentode sounds really sweet (I can confirm this), according to Thorsten in this position a triode D3a is even better than a 437A (Myself, I haven´t compared these two).
Good luck.
You bet. You can also use triodes like the EC8010, EC8020, 6C45P...and triode connected pentodes as the E280F, E180F...and others.
Because the D3a is a much, much cheaper tube (at least for now) and also cos´ wired like a triode this pentode sounds really sweet (I can confirm this), according to Thorsten in this position a triode D3a is even better than a 437A (Myself, I haven´t compared these two).
Good luck.
I was looking up the choke parts.
Lundal LL1638/10 series connected is a 10H 150ma 36 ohm choke. You have 20H which not made for LL1638. Or did you mean 10H on each rail? And that is why you put 20H there?
http://www.lundahl.se/pdfs/datash/1638.pdf
Lundal LL1673/10 series connected is a 10H 200ma 60 ohm choke.
http://www.lundahl.se/pdfs/datash/1673.pdf
Just want to check. As the choke values will change the voltage on the B+.
Lundal LL1638/10 series connected is a 10H 150ma 36 ohm choke. You have 20H which not made for LL1638. Or did you mean 10H on each rail? And that is why you put 20H there?
http://www.lundahl.se/pdfs/datash/1638.pdf
Lundal LL1673/10 series connected is a 10H 200ma 60 ohm choke.
http://www.lundahl.se/pdfs/datash/1673.pdf
Just want to check. As the choke values will change the voltage on the B+.
Hi,
It is a LL1638 20H. I know it is not on catalog.
When I originally requested the chokes for the B+ part of both monoblocks, the supplier got me these, didn´t even bother to ask why they aren´t on catalog.
The design calls for two 10Hy chokes on each rail so...use what you think is better there.
Later,
Luis
It is a LL1638 20H. I know it is not on catalog.
When I originally requested the chokes for the B+ part of both monoblocks, the supplier got me these, didn´t even bother to ask why they aren´t on catalog.
The design calls for two 10Hy chokes on each rail so...use what you think is better there.
Later,
Luis
In the power supply. I do not understand why the 5.5V 300B filiment is also coupled to the B+ via the 680K resistor?
Another question is why are there silicone diodes on the plates of the rectifier tube?
Thanks.
Another question is why are there silicone diodes on the plates of the rectifier tube?
Thanks.
The B+ is AC coupled to the cathode. It's a way of injecting the noise component of the B+ at the cathode in antiphase for PS noise cancellation. It also bypasses the the audio AC component, but into the B+, not to ground.
The the PS is using a hybrid bridge, with two of the diodes SS and two from the tube. This makes a more efficient bridge than using a second rectifier tube, but does not have the switching noise associated with SS diodes. The tube rectifier prevents reverse current into the SS diodes.
Sheldon
The the PS is using a hybrid bridge, with two of the diodes SS and two from the tube. This makes a more efficient bridge than using a second rectifier tube, but does not have the switching noise associated with SS diodes. The tube rectifier prevents reverse current into the SS diodes.
Sheldon
Sheldon you just mentioned two rectifiers. But, a single western electric 274 type A or B or any 5U4GB is able to do the job.
I want correct my one of my prior posts. The 5.5V filiment coupled to the B+ is for the D3A pentode not the 300B. As posted in my prior question.
gnomus said:
Yes if you have a center tapped transformer and want to do a full wave rectifier, but not if you want to do a bridge. You need 4 diodes for a bridge. You can use 4 SS diodes, 2 rectifier tubes, or one rectifier tube and two SS diodes. The schematic in question uses a bridge.
Sheldon
Thanks for clearing that up. I have mostly delt with solid state DIY. And had thought that a full wave tube rectifier was the tube equal of a solid state bridge. The next questions is why choose a bridge over a full wave?
This brings one more question to mind. When the 300B came out. There was no solid state rectifiers? So, how was DC applied to the 300B? As this would require a hefty tube rectifier(s). Or was just A/c used?
Thanks for you help.
This brings one more question to mind. When the 300B came out. There was no solid state rectifiers? So, how was DC applied to the 300B? As this would require a hefty tube rectifier(s). Or was just A/c used?
Thanks for you help.
- Status
- Not open for further replies.