Hello all, can any on this site recommend a power transformer for my new build? I want to use the Aikido octal board and the PS tube kit with the 5y3 rectifier tube. the 270cax from Hammond is recommended on the glassware audio site, but I don't know if it's a good match for the octal board....I have also heard of set ups with 2 transformers. 1 for the heaters and separte for the B+
Hammond or similar (Edcor?) will be your choices as you need three secondaries. As far as the Hammond 270CAX goes, the 6.3 volt winding might be a bit current-shy for use with four 6SN7 tubes. If memory serves, the octal board wires pairs of filaments in series so you will need 12 volts at 1.2 amps to power the four 6SN7s. The PS-Tube uses a voltage doubler for the 6SN7 filaments. According to Broskie's PS-1 power supply manual, a voltage doubler will need about 3.6 times the current input as it will output. So 1.2 amps times 3.6 = about 4 amps in. So you might need something like a Hammond 270EX. that has a 6.3 volt, 4 amp winding. The HT winding of a 270EX will have more than enough current so you might need to add some resistance to the HT supply at J1 on the PS-Tube board.
Cheers, S.
Cheers, S.
Thank you all. I just returned to the glassware site looking for my ps- tube kit and can't find it anywhere. J1 on the power supply board? to reduce the B+ I will have to remember that. I thought 12a and 12b on the octal were the resistors for B+
I saw the PS-1 earlier today on the glassware site but now it's gone! Did you get yours already? If you didn't then the the solid-sate rectified PS-1 might be an alternative, plus, the PS-1 has regulated B+. If you didn't get a PS-Tube and now go with solid state B+ you don't need a 5 volt winding. Transformer options become more varied. Antek Products (https://www.antekinc.com/power-transformers/) have decent, reasonably priced toroids with high and low voltage windings. Alternatively, two separate Triad toroids, one for filament and one for B+, is an option.
I guess I'm going to be building something else. sales at Glassware Audio just refunded me for the octal board and tube rectifier board with no explanation. what the heck?..........................I may have to go point to point.
You can get some nice octal Aikido boards directly from a PC board fab company. A generous person here on DiyAudio posted the Gerber files some time ago. I had some made and they look great. I have a 6SN7 Aikido line stage made with an older Glassware board that is an all in one. SS power supply rather than a tube rectifier with a single Antek toroid. I love it.
Here's the thread with the Gerber files:
https://www.diyaudio.com/community/threads/home-brewed-aikido-preamp.354383/
Here's the thread with the Gerber files:
https://www.diyaudio.com/community/threads/home-brewed-aikido-preamp.354383/
P-to-p really isn't difficult, that's the way I built the one I'm currently using. I'm using a 6X5 rectifier with a 20uF cap, then a Neurochrome Maida regulator board:
https://neurochrome.com/products/21st-century-maida-regulator
These are pricey but they are adjustable, sound fantastic and can be reused down the road for other projects. Really great for preamps.
Filaments are powered by 6V in > 6V out regulator boards sold by v4lve lover:
https://www.diyaudio.com/community/...pplies-mic5156-based-tube-amp-upgrade.382265/
Powered by two Antek transformers, one for the HV and one for the filaments (the filament board needs at least 6A tranny to power 4 6SN7s):
https://www.antekinc.com/as-05tc250-50va-250vx2-transformer/
https://www.antekinc.com/as-1206-100va-6v-transformer/
The whole thing sounds wonderful and it's dead quiet.
Or you could order the boards nerdorama linked to. I have some and am eager to try them.
will this work for my heaters? I have decided to use Broskies ps-21 power supply.
| Bulletins (PDF) | |
|---|---|
| Shipping Weight | 1.75 lbs (0.79 kg) |
| UNSPSC | 39121301 |
| UPC | 623980531311 |
| REACH Compliant | Yes (more info...) |
| RoHS Compliant | Yes (more info...) |
| Power Rating (VA) | 50 |
| Secondary (RMS) Series | 24V C.T. @ 2.08A |
| Secondary (RMS) Parallel | 12V @ 4.16A |
| % Voltage Regulation | 13 |
1182L12
A 1182L12 should be fine.
Some things about the PS-21 you should be aware of:
1. C14 (x2) as supplied by Broskie might be 16 volt-rated caps. The raw rectified filament DC that the C14s see might run slightly higher than 16 volts. As a safety measure, replace these with 25 volt rated caps.
2. Unlike some of Broskie's other supplies, the filament negatives aren't tied to a portion of the B+ supply through a two-resistor dividing network. The divider is to float the filaments above ground potential and make life easier on the tubes. You might have to implement this yourself or if you are using 6SN7 tubes the floating arrangement might not be necessary. I have little experience with 6SN7s, others should comment.
3. Make sure you put the components on the correct side of the board. The correct side is the one that has the PS-21 and CAUTION High Voltage stenciling.
4. As a safety measure, I like to put a layer of Kapton tape on the board where the traces might might "interfere" with the heat sinks. This primarily around the B+ 'sink.
5. Don't forget to buy some heatsink thermal compound to use when mounting the regs to the 'sinks.
Cheers, S.
Some things about the PS-21 you should be aware of:
1. C14 (x2) as supplied by Broskie might be 16 volt-rated caps. The raw rectified filament DC that the C14s see might run slightly higher than 16 volts. As a safety measure, replace these with 25 volt rated caps.
2. Unlike some of Broskie's other supplies, the filament negatives aren't tied to a portion of the B+ supply through a two-resistor dividing network. The divider is to float the filaments above ground potential and make life easier on the tubes. You might have to implement this yourself or if you are using 6SN7 tubes the floating arrangement might not be necessary. I have little experience with 6SN7s, others should comment.
3. Make sure you put the components on the correct side of the board. The correct side is the one that has the PS-21 and CAUTION High Voltage stenciling.
4. As a safety measure, I like to put a layer of Kapton tape on the board where the traces might might "interfere" with the heat sinks. This primarily around the B+ 'sink.
5. Don't forget to buy some heatsink thermal compound to use when mounting the regs to the 'sinks.
Cheers, S.
Hi, thanks for the reply. c14 is rated at 16v. Increasing these will make them even taller. I considered using a low-profile case for this or possibly making holes to accommodate the taller caps. I will be using all 6sn7 tubes as I am trying to make it a line amplifier. I also forgot to put grease on the supplied micas. .🙄...Can you recommend a starting point for the r12 resistor? I am not sure about that so I left it out for now. this is the single secondary transformer I am going to use.
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| Product Attribute | Attribute Value | Select Attribute |
|---|---|---|
| Manufacturer: | Hammond | |
| Product Category: | Power Transformers | |
| RoHS: | Details | |
| Primary Voltage Rating: | 115 VAC, 230 VAC | |
| Secondary Voltage Rating: | 240 VAC | |
| Power Rating: | 50 VA | |
| Secondary Current Rating: | 208 mA | |
| Mounting Style: | Chassis | |
| Primary Winding: | Dual Primary Winding | |
| Secondary Winding: | Single Secondary Winding | |
| Height: | 1.5 in | |
| Outside Diameter: | 3.25 in | |
| Series: | 1182 | |
| Brand: | Hammond Manufacturing | |
| Operating Frequency: | 50 Hz, 60 Hz | |
| Packaging: | Bulk | |
| Product Type: | Toroidal Transformers | |
| 1 | ||
| Subcategory: | Transformers | |
| Termination Style: | Wire Leads | |
| Unit Weight: | 1.750 lbs |
Select at least one checkbox above to show similar products in this cate
Attachments
I might have an earlier version of the PS-21 than yours. The R12 on mine sets the filament voltage and is between the ADJ pin on the LD1085 and ground. If this is the same on your board Broskie usually supplies 3 resistors for each reg. Assuming you are wiring two 6SN7 filaments in series (therefore 12 volts) you can choose 12 volts (1.07K on mine) or 12.6 volts (1.13K on mine). Under-running them at 12 volts, instead of 12.6, could extend tube life and the circuit will run virtually the same as at 12.6 volts.
The Hammond should work fine. Other good choices are similar transformers form Triad (from Mouser) or perhaps there might be something similar from Antek.
S.
The Hammond should work fine. Other good choices are similar transformers form Triad (from Mouser) or perhaps there might be something similar from Antek.
S.
If you haven't bought your filament trannies yet consider this Antek with filament and HT in one. The price is right and shipping within the USA shouldn't be too expensive.
https://www.antekinc.com/as-1t250-100va-250v-transformer/
AS-1T250 - 100VA 250V TRANSFORMER
https://www.antekinc.com/as-1t250-100va-250v-transformer/
OOPS, sorry, you need two 12 volt windings. The Antek above has two 6 volt windings. Apologies for the mis-direction.
1. The first transformer is a dual 12-volt parallel or 24v center tapped. the second is a single 240vac with a 208ma current rating.
2. Page 8 shows what he recommends for transformers and page 15 shows an RC power supply and a resistor for setting up the b plus.
I am confused about the r12 resistor on the octal board on page 15
2. Page 8 shows what he recommends for transformers and page 15 shows an RC power supply and a resistor for setting up the b plus.
I am confused about the r12 resistor on the octal board on page 15
Attachments
You need two separate 12v windings.. I use two small toroids, a dual 12v and a 115-0-115 to give about 280v pre regulator, and 220v to the Aikido.
The R12 on the PS21 is not the same as R12 on the Aikido. You can omit the one on this if using a PS21 unless you want to lose some HT volts.
The R12 on the PS21 is not the same as R12 on the Aikido. You can omit the one on this if using a PS21 unless you want to lose some HT volts.
HI, leave the r12 resistor on the octal board out?
will this work for my heaters? I have decided to use Broskies PS-21 power supply.
will this work for my heaters? I have decided to use Broskies PS-21 power supply.
| Bulletins (PDF) | |
|---|---|
| Shipping Weight | 1.75 lbs (0.79 kg) |
| UNSPSC | 39121301 |
| UPC | 623980531311 |
| REACH Compliant | Yes (more info...) |
| RoHS Compliant | Yes (more info...) |
| Power Rating (VA) | 50 |
| Secondary (RMS) Series | 24V C.T. @ 2.08A |
| Secondary (RMS) Parallel | 12V @ 4.16A |
| % Voltage Regulation | 13 |