I was just fooling around with those tubes... I don't have much interest right now since I'm using Full Music 12AX7. I was just curious to know how the 6922 would have sounded.
Do
Where did you buy your Full Music Tubes from? they are for sale on ebay, is it safe to buy them from ebay?
It is usually ok to buy from Ebay. I do all the time. You need to check the seller's rating... Usually over 100+ sales with 99% feedback is good. For tubes though, I would go with sellers that specializes and have over 1000 sales with more than 98.5% of feedback...
I bought my tubes from Parts ConneXion - The authority on hi-fi DIY parts and components
Thanks
Do
Hello,
I connected without valves and ... voila.
It seems to work. Some measurements to see if it is correct with a 150V secondary transformer:
- Vout pcb tube-i-Zator no load is 211V.
- Vout pcb tube-i-Zator with load ranges SSHV is 164v but varies a little.
- Vout SSHV (connected no load) 150V although it takes 30-40 minutes to reach this voltage. Start with 138V
The IRF840 MOSFET reaches 80 degrees C (70C heatsinks)
. Ambient temperature 25C
Is correct?, is it normal temperature so IRF840?, I put the heatsink on the list of materials.
regards
I connected without valves and ... voila.
It seems to work. Some measurements to see if it is correct with a 150V secondary transformer:
- Vout pcb tube-i-Zator no load is 211V.
- Vout pcb tube-i-Zator with load ranges SSHV is 164v but varies a little.
- Vout SSHV (connected no load) 150V although it takes 30-40 minutes to reach this voltage. Start with 138V
The IRF840 MOSFET reaches 80 degrees C (70C heatsinks)
. Ambient temperature 25CIs correct?, is it normal temperature so IRF840?, I put the heatsink on the list of materials.
regards
Just check the spec on IRF840 for max temp and junction point max temp. I believe the max temp for junction point is 150C
Ciao!
Do
I used a multimeter that can measure the temperature with a probe. Like this:
MULTIMETRO 3 1/2 DIGITOS TEMPERATURA CAPACIMETRO FRECUENCIMETRO | BRIELCO ARTICULOS DE ELECTRONICA Y COMPONENTES ELECTRONICOS
I've been running mine for some time now at this temperature and it is quite fine. It will most probably shorten its life span but...
Ciao!
Do
Hi,
My setup is tubeizator+ SShv for 6n2p tube. The materials are the same values as the BOM list. I used the filter capacitor 220uf 450V + 470uF 450V.
The problem is that my transformer has a 230V primary (official voltage Spain) and my house gets 222-223V.
The measures in the secondary transformer 146-147V (loaded) and after grinding and filtering 204-205V.
When I connect the sshv the input voltage is162V-163V. If regulated to 150V output, i have a difference of 12v-13v between input and output in the ssh. I have read that has to be 20-25v.
My transformer has a secondary 0-150V 0.2A and 0-9V 3A.
I put an email to the manufacturer and advised me to add the secondary 150V 9V (159V total theoretical) to get more voltage. With 3A I have to spare.
I guess for the SSHV not get too hot I have to adjust for a difference of 25V. The output may be between 150V and 155V
How do you see?
Br
Al
My setup is tubeizator+ SShv for 6n2p tube. The materials are the same values as the BOM list. I used the filter capacitor 220uf 450V + 470uF 450V.
The problem is that my transformer has a 230V primary (official voltage Spain) and my house gets 222-223V.
The measures in the secondary transformer 146-147V (loaded) and after grinding and filtering 204-205V.
When I connect the sshv the input voltage is162V-163V. If regulated to 150V output, i have a difference of 12v-13v between input and output in the ssh. I have read that has to be 20-25v.
My transformer has a secondary 0-150V 0.2A and 0-9V 3A.
I put an email to the manufacturer and advised me to add the secondary 150V 9V (159V total theoretical) to get more voltage. With 3A I have to spare.
I guess for the SSHV not get too hot I have to adjust for a difference of 25V. The output may be between 150V and 155V
How do you see?
Br
Al
Last edited:
Hi Alberto,
Could you post a picture of your hookup? This can help troubleshooting.
Ciao!
Do
Thanks guys for the help.
I added the transformer secondary as directed by the manufacturer and get exactly the required voltage. I connected and everything went well ...
... But when you connect to both the 0-9V to heat the tubes, DISASTER!. A filter capacitor (3900UF 16V) is inflated and almost explodes.
I turned off the electric current time. The capacitor closest to the star ground has been deformed. The rest looks good.
I reconnected each transformer secondary separately and it seems that everything works well, yet I will replace the damaged capacitor.
I think I connected well, anyway, I sent the transformer manufacturer and I will have to modify to get 160V.
I do not think that does more rare experiments.
I added the transformer secondary as directed by the manufacturer and get exactly the required voltage. I connected and everything went well ...
... But when you connect to both the 0-9V to heat the tubes, DISASTER!. A filter capacitor (3900UF 16V) is inflated and almost explodes.
I turned off the electric current time. The capacitor closest to the star ground has been deformed. The rest looks good.I reconnected each transformer secondary separately and it seems that everything works well, yet I will replace the damaged capacitor.
I think I connected well, anyway, I sent the transformer manufacturer and I will have to modify to get 160V.
I do not think that does more rare experiments.
Hi Do,
Sorry for the delayed response. I wanted some time to have 28R resistors to "burn in". After switching the resistors out, the instruments and vocals are much more separate and "spaced apart" from each other even after leaving the DAC on for 5 or more hours. It seems much better to me.
Regarding the 6922 tubes, I just put them in. I did nothing special. I of course set the heater switch to the 6n2P side though. I did not notice any strange sounds coming from the tubes in the DAC. Are you sure the Mullard E88CC's are not microphonic? What year are the Mullards. I have never heard a paire of E88CC Mullards before, but understand them to sound very nice (balanced, smooth, wide soundstage). Are you sure the heater voltage is set to exactly 6.3V? Also, is the voltage coming from the HV shunt boards exactly (or very close to) 150V?
Greg
Hi Greg,
Glad to hear the good news! I'm really happy as well with the 32R I put in. I'm using the volumite so I can adjust the output without using a preamp.
My shunt is set to 150V but only gets there when temperature settle in. It starts around 142V then climbs and stay still at 150V after about 10-15min.
The filament is 6.3V on the pin! I've used those E88CC on a X10 buffer with 35V supply and they shined even at low voltage. I also used them in a SP-10 preamp (260V) and they worked perfectly. They are OS tubes and I believe they're from the late 60's, early 70's era... But don't quote me on this. They're really smooth tubes. I don't know how different than my 12AX7 but would love to find out for sure...
Ciao!
Do
Hi,
My progress. I changed the transformer for a 25v difference between Vin and Vout in sshv.
I have adjusted to 151.5v Vout. The measures with the tubes placed (6n2p-ev) are:
L R
1. 151,5--------151,5
2. 76------------77
3. 76,4---------77,4
4. 6,3----------- 0
5. 0--------------6,3
6. 76------------77
7. 0 ------------ 0
8. 0,254--------0,248
9. 0 ------------0
Measured in volts. IS CORRECT?
Thanks
My progress. I changed the transformer for a 25v difference between Vin and Vout in sshv.
I have adjusted to 151.5v Vout. The measures with the tubes placed (6n2p-ev) are:
L R
1. 151,5--------151,5
2. 76------------77
3. 76,4---------77,4
4. 6,3----------- 0
5. 0--------------6,3
6. 76------------77
7. 0 ------------ 0
8. 0,254--------0,248
9. 0 ------------0
Measured in volts. IS CORRECT?
Thanks
If you don't have a transfo you will need to limit the current in some way... The circuit calls for 150V 100VA if I remember correctly.
120V AC should give you close to 170V DC minus the voltage drop on the resistor near the filtering cap and the shunt reg. To me, a transfo is a must.
You should get something similar to this transfo
Antek - AS-1T150
Ciao!
Do
Hi Alberto,
Did you get it running? Sorry, I've been away of the thread for some time... Too busy lately!
Ciao!
Do
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