If you want to buy some resistors, values between 11 and 12 ohms are likely what that R1 should change to. Also changing the 270 Ohm 5W resistors out to 300R 5W resistors will alleviate some C4S thermal load.
Tube Rolling
- Thread starter TurbOSquiD77
- Start date
TurbOSquiD77
New member
Caucasian Blackplate said:
Awesome. Looking at Mouser for 300R 5W:
Vishay/Dale RE60G3000C02 chassis mount wirewound 1%
Ohmite 805F300E chassis mount wirewound 1%
Vishay/Draloric AC05000003000JAC00 Cement Filled Ceramic 5%
Ohmite TUM5J300E Cement Filled Ceramic 5%
Xicon 280-CR5-300-RC Cement Filled Ceramic 5%
I read inductive types are good, and chassis mount types need proper chassis surface area for the heat sink to function at optimal temps. Unsure if 1% tolerance is favored.
TurbOSquiD77
New member
Interesting....
The amp has been on for 5 hours. No headphones, and no RCA's connected (listening to other amp).
I go upstairs for an hour and come down to the power transformer dissipating heat into the air more than usual.
The chassis is hotter than usual. Slight smell (if any).
Rapidly fluctuating pissed off cyborg noise from the power transformer. It's done this before, and during my voltage tests, but not as audible.
Took quite a while for the PT-8 to cool down.
Fuse looks good.
Sleep.
;D
The amp has been on for 5 hours. No headphones, and no RCA's connected (listening to other amp).
I go upstairs for an hour and come down to the power transformer dissipating heat into the air more than usual.
The chassis is hotter than usual. Slight smell (if any).
Rapidly fluctuating pissed off cyborg noise from the power transformer. It's done this before, and during my voltage tests, but not as audible.
Took quite a while for the PT-8 to cool down.
Fuse looks good.
Sleep.
;D
An angry power transformer will come with voltages that aren't what they are supposed to be.
TurbOSquiD77
New member
Agreed, haha.
Forgot to solder an LED and resistor after cleaning up some solder joints. Fixed, voltage test, all is good. E80CC showed up today so I thought I'd give her a shot, and then the 12BH7A.
5998/E80CC/6005's:
470 ohm at r1 on low current board - with e80cc
Terminal Voltage (DC)
Low Current C4S
IA 150V 150.1V
OA 60-90V 67.3V
KregA 3-6V 5.45V
bRegA 150V 149V
IB 150V 149.1V
OB 60-90V 64.1V
KregB 3-6V 5.37V
bRegB 150V 150.1V
High Current C4S ( / indicates left and right High Current board measurements)
IA 190V 193/192.9V
OA 150V 149/150V
bA 0V .3/.5mV
IB 0V .3/.5mV
OB 90-110V 74.4/76.8V
bB 150V 149/150V
5998/12BH7A/6005's:
124 ohm at r1 on low current board
Terminal Voltage (DC)
Low Current C4S
IA 150V 150V
OA 60-90V 63.3V
KregA 3-6V 6.40V
bRegA 150V 148.9V
IB 150V 148.9V
OB 60-90V 65V
KregB 3-6V 6.59V
bRegB 150V 150V
High Current C4S ( / indicates left and right High Current board measurements)
IA 190V 195/194.7V
OA 150V 148.9/150V
bA 0V .3/.5mV
IB 0V .3/.5mV
OB 90-110V 75.3/73.2V
bB 150V 148.9/150V
I have a few 1/4 W resistors between 11 and 12.1 Ohms. Also picked up a few different brands of 5W 300R wirewound ceramic/cement resistors.
Thank you Paul I appreciate you giving your knowledge. Hit me with explanations if you could. I'll make sense of them, and I like figuring things out.
-T
Forgot to solder an LED and resistor after cleaning up some solder joints. Fixed, voltage test, all is good. E80CC showed up today so I thought I'd give her a shot, and then the 12BH7A.
5998/E80CC/6005's:
470 ohm at r1 on low current board - with e80cc
Terminal Voltage (DC)
Low Current C4S
IA 150V 150.1V
OA 60-90V 67.3V
KregA 3-6V 5.45V
bRegA 150V 149V
IB 150V 149.1V
OB 60-90V 64.1V
KregB 3-6V 5.37V
bRegB 150V 150.1V
High Current C4S ( / indicates left and right High Current board measurements)
IA 190V 193/192.9V
OA 150V 149/150V
bA 0V .3/.5mV
IB 0V .3/.5mV
OB 90-110V 74.4/76.8VbB 150V 149/150V
5998/12BH7A/6005's:
124 ohm at r1 on low current board
Terminal Voltage (DC)
Low Current C4S
IA 150V 150V
OA 60-90V 63.3V
KregA 3-6V 6.40VbRegA 150V 148.9V
IB 150V 148.9V
OB 60-90V 65V
KregB 3-6V 6.59VbRegB 150V 150V
High Current C4S ( / indicates left and right High Current board measurements)
IA 190V 195/194.7V
OA 150V 148.9/150V
bA 0V .3/.5mV
IB 0V .3/.5mV
OB 90-110V 75.3/73.2VbB 150V 148.9/150V
I have a few 1/4 W resistors between 11 and 12.1 Ohms. Also picked up a few different brands of 5W 300R wirewound ceramic/cement resistors.
Thank you Paul I appreciate you giving your knowledge. Hit me with explanations if you could. I'll make sense of them, and I like figuring things out.
-T
Yeah, you could go down to 12.1 for R1A on the high current C4S for each side. This will give the 6AQ5's more current, as we want the cathode follower and shunt regulator to run roughly the same current.
When you pull more current through the circuit, you pull more current through the power supply resistors. That is the reason for my recommendation to go to a 10W part. When you set the C4S to deliver more current, the MJE5731A will have to dissipate more heat. By going to a 300 Ohm resistor in each leg of the power supply, that effect is mitigated by lowering the voltage available at the input of the C4S.
When you pull more current through the circuit, you pull more current through the power supply resistors. That is the reason for my recommendation to go to a 10W part. When you set the C4S to deliver more current, the MJE5731A will have to dissipate more heat. By going to a 300 Ohm resistor in each leg of the power supply, that effect is mitigated by lowering the voltage available at the input of the C4S.
TurbOSquiD77
New member
Awesome, I will try and see how she performs!
Just to clarify.... should those be 5 or 10 watt 300R resistors in the power supply? I have a few types of 5W ceramic/cement.
Is Kreg okay, or will the other changes adjust the voltage here?
Just to clarify.... should those be 5 or 10 watt 300R resistors in the power supply? I have a few types of 5W ceramic/cement.
Is Kreg okay, or will the other changes adjust the voltage here?
5W parts will be OK for the 300 Ohm power supply resistors.
The Kreg voltage will change when you put the 12.1 Ohm resistors in. This change will not need to be undone if you go back to the 12AU7 or E80CC.
The Kreg voltage will change when you put the 12.1 Ohm resistors in. This change will not need to be undone if you go back to the 12AU7 or E80CC.
TurbOSquiD77
New member
Nice, good to know! Thank you
-T
-T
TurbOSquiD77
New member
Caucasian Blackplate said:
Hey, hope the show was awesome!
I finally got to switch out the power supply resistors to 300R 5W, 124 Ohms at R1 low current, and 12.1 Ohms at R1A on the high current boards. Those wirewounds were quite the task!
Here are my numbers:
5998/12bh7a - 124 ohm at r1 on low current board - 12.1 ohm at R1 on high current - 300R psu resistors
Terminal Voltage (DC)
Low Current C4S
IA 150V 149.2V
OA 60-90V 63V
KregA 3-6V 5.25V
bRegA 150V 149.2V
IB 150V 148.7V
OB 60-90V 64.8V
KregB 3-6V 5.58V
bRegB 150V 148.7V
High Current C4S ( / indicates left and right High Current board measurements)
IA 190V 189.9/190V
OA 150V 148.7/149.2V
bA 0V .4/.5mV
IB 0V .3/.5mV
OB 90-110V 75.2/72.8VbB 150V 148.7/149.2V
What causes OB to read low?
-T
TurbOSquiD77
New member
Got around to measuring with the 6080. All are exactly or close to the same readings except OB on the high current boards. Is this due to the 5998 having higher plate resistance, and more than twice the moo's? I read that this won't affect heat, and that what does affect heat is the current the tube is pulling from the transformer. Apparently the 6080/6AS7G and 5998 are close according to a source found on head fi.
5998:
Class A Amplifier
Plate Voltage ................................. 110 V
Grid No. 1 Voltage Derived from
Cathode Bias Resistor ....................... 105 Ω
Amplification Factor .......................... 5.4
Plate Resistance (approx) ..................... 350 Ω
Transconductance .............................. 15.5K μ
Plate Current ................................. 100 mA
6AS7G:
Class A Amplifier
Plate Voltage ................................. 135 V
Grid No. 1 Voltage Derived from
Cathode Bias Resistor ....................... 250 Ω
Amplification Factor .......................... 2
Plate Resistance (approx) ..................... 280 Ω
Transconductance .............................. 7000 μ
Plate Current ................................. 125 mA
Let's measure with the 6080 vs the 5998 measurements in my post just before this one:
6080/12bh7a - 124 ohm at r1 on low current board - 12.1 ohm at R1 on high current - 300R psu resistors
Terminal Voltage (DC)
Low Current C4S
IA 150V 149.2V
OA 60-90V 62.9V
KregA 3-6V 5.26V
bRegA 150V 149.2V
IB 150V 148.7V
OB 60-90V 64.8V
KregB 3-6V 5.58V
bRegB 150V 148.7V
High Current C4S ( / indicates left and right High Current board measurements)
IA 190V 189.1/189V
OA 150V 148.7/149.2V
bA 0V .3/.5mV
IB 0V .3/.5mV
8) OB 90-110V 87.3/87V
bB 150V 148.7/149.2V
Is this okay or should I look into bringing high current OB's voltage back up when running the 5998? However, OB on the low current board is fine. Interesting! I see pcb traces going through R2B, R1B, Y/Y+, and in the opposite direction being output caps/headphone jack/OB low current board, as well as pin 6 and 3 on the 5998 socket.
Possibilities:
R2B (22KΩ 5W)
R1B (31.6Ω ⅛W)
Y/Y+ (33KΩ ⅛W)
Nice post btw - just for everyones reference:
http://bottlehead.com/smf/index.php?topic=4965.0
Not about to go that route if it involves much more than component value changes. That is, if changing R2B..etc is where this is heading. Just hoping to work towards keeping her healthy
Huzzuh!!!!
5998:
Class A Amplifier
Plate Voltage ................................. 110 V
Grid No. 1 Voltage Derived from
Cathode Bias Resistor ....................... 105 Ω
Amplification Factor .......................... 5.4
Plate Resistance (approx) ..................... 350 Ω
Transconductance .............................. 15.5K μ
Plate Current ................................. 100 mA
6AS7G:
Class A Amplifier
Plate Voltage ................................. 135 V
Grid No. 1 Voltage Derived from
Cathode Bias Resistor ....................... 250 Ω
Amplification Factor .......................... 2
Plate Resistance (approx) ..................... 280 Ω
Transconductance .............................. 7000 μ
Plate Current ................................. 125 mA
Let's measure with the 6080 vs the 5998 measurements in my post just before this one:
6080/12bh7a - 124 ohm at r1 on low current board - 12.1 ohm at R1 on high current - 300R psu resistors
Terminal Voltage (DC)
Low Current C4S
IA 150V 149.2V
OA 60-90V 62.9V
KregA 3-6V 5.26V
bRegA 150V 149.2V
IB 150V 148.7V
OB 60-90V 64.8V
KregB 3-6V 5.58V
bRegB 150V 148.7V
High Current C4S ( / indicates left and right High Current board measurements)
IA 190V 189.1/189V
OA 150V 148.7/149.2V
bA 0V .3/.5mV
IB 0V .3/.5mV
8) OB 90-110V 87.3/87V
bB 150V 148.7/149.2V
Is this okay or should I look into bringing high current OB's voltage back up when running the 5998? However, OB on the low current board is fine. Interesting! I see pcb traces going through R2B, R1B, Y/Y+, and in the opposite direction being output caps/headphone jack/OB low current board, as well as pin 6 and 3 on the 5998 socket.
Possibilities:
R2B (22KΩ 5W)
R1B (31.6Ω ⅛W)
Y/Y+ (33KΩ ⅛W)
Nice post btw - just for everyones reference:
http://bottlehead.com/smf/index.php?topic=4965.0
Not about to go that route if it involves much more than component value changes. That is, if changing R2B..etc is where this is heading. Just hoping to work towards keeping her healthy
Huzzuh!!!!
When OA and OB on the small C4S board are a little low in their range (like yours) that will bring the OA and OB voltages of the high current C4S boards that feed the 6080 down a little bit as well.
To nudge them back up, the R1 on the center small C4S board will have to be lowered a bit. If you're at 124R now, try a 113R and see if that perks up your plate voltages (and consequently 6080 cathode voltages) a little bit.
To nudge them back up, the R1 on the center small C4S board will have to be lowered a bit. If you're at 124R now, try a 113R and see if that perks up your plate voltages (and consequently 6080 cathode voltages) a little bit.
TurbOSquiD77
New member
Cool, I will try and dial her in. Thanks Paul
Will having the cathode voltage low at OB on the high current boards be a problem if I continue to use the 5998?
Will having the cathode voltage low at OB on the high current boards be a problem if I continue to use the 5998?
Nah, better a little low than really high, though there's some thermal headroom on those heatsinks.
TurbOSquiD77
New member
Numbers are looking good after the adjustments - will share soon!
Quick question before hitting the hay....
I've replaced the stock 270R 5W power resistors with 300R 5W. Easy, kind of!
I am now (after some patience and time and in the end rebuilding the entire power supply with new parts anyways [UF4007-GP-TP Ultra Fast rectifiers - found em!
]) running 300R 10W.
Holy hell that's a tight fit - they are pretty long.
All voltages checked out great - same or better numbers than those previously posted.
I think I'm hearing some clipping. Very light, seems intermittent, and at odd times on the same track. But sometimes at the exact same time, on the same track. It's just a little snap/pop right? But, the C2A should be more than enough for Beyers and Senns. hmmm
Happy listening, pics to come.
-T
Quick question before hitting the hay....
I've replaced the stock 270R 5W power resistors with 300R 5W. Easy, kind of!
I am now (after some patience and time and in the end rebuilding the entire power supply with new parts anyways [UF4007-GP-TP Ultra Fast rectifiers - found em!
]) running 300R 10W. Holy hell that's a tight fit - they are pretty long.
All voltages checked out great - same or better numbers than those previously posted.
I think I'm hearing some clipping. Very light, seems intermittent, and at odd times on the same track. But sometimes at the exact same time, on the same track. It's just a little snap/pop right? But, the C2A should be more than enough for Beyers and Senns. hmmm
Happy listening, pics to come.
-T
TurbOSquiD77
New member
Seems as if my soldering iron (not me of course) caused some damage to the Nichicons - metal is showing a bit. I have new ones on the way. Power transformer is making more noise than usual. However, all voltages check out great.
Can I redo the incoming voltage test with everything connected? Since I've modified the power resistors with 300R 10W's. I also had to curve the rectifiers in the power supply quite a bit to get them around the resistors. This might be contributing to something but not sure.
I've also been battling dirty power coming from my PC. What a nightmare. Many steps have been taken, and next is a power conditioner.
Can I redo the incoming voltage test with everything connected? Since I've modified the power resistors with 300R 10W's. I also had to curve the rectifiers in the power supply quite a bit to get them around the resistors. This might be contributing to something but not sure.
I've also been battling dirty power coming from my PC. What a nightmare. Many steps have been taken, and next is a power conditioner.
Yeah, this is part of the process of doing strange modifications. There may be problems that come up that will take some time and effort to resolve on your own (I haven't tried the mods, so I'm not sure what might be happening).
Your incoming line voltage is very, very unlikely to change appreciably. If you live in an area where this happens, you will already be very aware!
What happened to the UF4007's that came with the kit? Was there an issue that required their removal? From where did you source the new diodes?
The power transformer shouldn't be making any additional noise unless you've put a considerable additional load on it. This would generally be reflected by low voltage measurements and hot parts. Just as a test, you can pull all the tubes out and turn the kit on, then listen for the noise again.
Your incoming line voltage is very, very unlikely to change appreciably. If you live in an area where this happens, you will already be very aware!
What happened to the UF4007's that came with the kit? Was there an issue that required their removal? From where did you source the new diodes?
The power transformer shouldn't be making any additional noise unless you've put a considerable additional load on it. This would generally be reflected by low voltage measurements and hot parts. Just as a test, you can pull all the tubes out and turn the kit on, then listen for the noise again.
TurbOSquiD77
New member
Totally understand! I think I've created my own confusion....Caucasian Blackplate said:
Long story short I believe my new dac is the source of a very small pop/clipping sound which is randomly present in my music. New dac in conjunction with installing 10W power resistors (and second guessing my fitment/soldering, damn things are long!) made me think that the C2A power supply was the source of the issue.
I rebuilt the entire power supply by properly desoldering, removing, cleaning with Caig Deoxit D5/D100, re positioning brand new parts along with the 10W 300R, soldering with Cardas silver solder (with lead), and cleaning with Deoxit D5/D100 and a pick to scrape the flux, topping it off with Deoxit Shield. Cleaned the transformer leads as well in the same manner. Everything looks super good!Caucasian Blackplate said:
Sourced all parts from Mouser, the exact values of the stock kit.
294-270K-RC
http://www.mouser.com/Search/ProductDetail.aspx?R=294-270K-RCvirtualkey21980000virtualkey294-270K-RC
UF4007GP-TP
http://www.mouser.com/Search/ProductDetail.aspx?R=UF4007GP-TPvirtualkey54720000virtualkey833-UF4007GP-TP
Caucasian Blackplate said:
It seems as if the power transformer and I have a love/hate relationship. Every time I change something, rebuild, or upgrade I find myself with the notion that the transformer is louder and/or hotter than before. Maybe it's because I'm worried. Maybe it's because I goofed (yep once lol). But I remember that when I did goof, the transformer was much more crunchy pissed cyborg sounding and HOT than it is now. Transformer hum is always audible, but only when I put my ear 6-12" away. It's a little bit higher pitched of a hum, not low and smooth. It does get hot... typically I can grab the transformer for 5 seconds or longer before needing to let go. That is, when she's been on for a couple hours pumpin' jams. I never see smoke, but do see heat dissipating which can be mistaken for smoke depending on lighting.
Those 10W resistors are huge! Can I connect the diodes to the same terminals, but in a different fashion? Such as, upper vs. lower terminal. This would help positioning them immensely, and also allow me to straighten the diodes. As of now, a couple of the diodes are curved to fit around the resistors, as the resistor leads won't allow me to move any further away from the diodes. Or, I can just use 5W resistors if 10W isn't absolutely needed, and without consequence.
Thanks Paul,
I'll try to keep the questions to whether or not I can do something, or what parts to use, rather than spewing my issue before taking all the troubleshooting steps. I have come to the conclusion my issue is not the C2A, it is my Amanero USB in the dac that is causing a random pop noise. C2A sounds good right now
-T
The 10W power supply resistors aren't necessary, just use the 5W ones.
Deoxit is a cleaner for connectors. I would recommend against using it while soldering. The solder Flux exists to clean and prep the joint for you, and if Deoxit leaves behind any corrosion inhibitors, it may actually make soldering more difficult.
Deoxit is a cleaner for connectors. I would recommend against using it while soldering. The solder Flux exists to clean and prep the joint for you, and if Deoxit leaves behind any corrosion inhibitors, it may actually make soldering more difficult.
TurbOSquiD77
New member
Mental note made. May only use Deoxit for post solder joint cleaning - it does work very well to remove flux residue. I did not realize the solder flux cleaned the joint so well before hardening. Thought it was just a little thing*
Popping issue fixed by using ASIO Bridge software. Sounding good now
Will the diodes be okay being curved a bit? From a physics perspective I'm not quite sure.
Popping issue fixed by using ASIO Bridge software. Sounding good now
Will the diodes be okay being curved a bit? From a physics perspective I'm not quite sure.
