I have had had a 45 tubed TSE running with a PQ5EV3 (3.5A instead of 5A) for while now without any problems, including being accidentally left on overnight a few times. It has some extra heat sinking, but doesn't seem to run too hot - 2A3 tubes would probably kill it though.
Thanks Grumpish. However my TSE runns with 300b. I don’t know if this pq5ev3 can handle these tubes. Any way I bought a pair pq5ev3 for little money.
I see an ebay vendor sales pq3ev5 that I think are chinese,. May be these are not reliable.
Need suggestions on power transformers.
I have now tried both the Hammond 370EX and 370HX. Both have an audible buzz from about 2 ft away.
This is probably fine with speakers but since the headphone amp is close to my listening position, I can hear the buzz when nothing is playing.
Which brands/types of PT are of higher quality and are expected to operate quieter?
P.S. I am selling the 370EX at a nice discount. If I can't return the 370HX, I will do the same. PM me if interested.
I have now tried both the Hammond 370EX and 370HX. Both have an audible buzz from about 2 ft away.
This is probably fine with speakers but since the headphone amp is close to my listening position, I can hear the buzz when nothing is playing.
Which brands/types of PT are of higher quality and are expected to operate quieter?
P.S. I am selling the 370EX at a nice discount. If I can't return the 370HX, I will do the same. PM me if interested.
I’m curious about the ClassicTone line of guitar power transformers. I’ve never heard one used for hifi but they seem quiet enough and run a little cooler than the Edcor I own. Price seems competitive too.
baker8, yes I've looked at those as well.
These 2 models seem to be compatible with 45's:
Marshall JMP 50W Plexi and JTM50 Power Transformer, 1202-118
HiFi Power Transformer, 372FX
Did you figure this one out ? I'm running 45's and my B- measures over 200V
These 2 models seem to be compatible with 45's:
Marshall JMP 50W Plexi and JTM50 Power Transformer, 1202-118
HiFi Power Transformer, 372FX
Did you figure this one out ? I'm running 45's and my B- measures over 200V
I was looking at this one for the static shield and versatility. It should work for a 300B/45. $108.42 for 1. $72.61 each if purchased in quantities over 18.
http://www.classictone.net/40-18073.pdf
Yea, that looks good too. Although B+ will high for 45's with the standard power supply parts (even bringing the first cap down to 4.7u)
On a similar note, can someone help me make sense of the attached guide by Hammond.
For B+, the HV secondary is in the "Full Wave Capacitor Input Load" arrangement, correct?
If so, the doc states:
Vpeak DC = 0.71 x Sec V AC
Vavg DC = 0.45 x Sec V AC
I DC = I AC
Taking the 370(EX, FX, HX etc), with 550VCT, this would put
Vpeak = 390 VDC
Vavg = 247 VDC
It doesn't correlate with the voltages I observe on the first 47uF filter caps, which are closer to 330-350VDC when everything is biased.
What I am I missing?
Additionally, how should Vavg in this calc be used? Should we plug in the target B+ we are looking for and choose the transformer based on that ?
On a similar note, can someone help me make sense of the attached guide by Hammond.
For B+, the HV secondary is in the "Full Wave Capacitor Input Load" arrangement, correct?
If so, the doc states:
Vpeak DC = 0.71 x Sec V AC
Vavg DC = 0.45 x Sec V AC
I DC = I AC
Taking the 370(EX, FX, HX etc), with 550VCT, this would put
Vpeak = 390 VDC
Vavg = 247 VDC
It doesn't correlate with the voltages I observe on the first 47uF filter caps, which are closer to 330-350VDC when everything is biased.
What I am I missing?
Additionally, how should Vavg in this calc be used? Should we plug in the target B+ we are looking for and choose the transformer based on that ?
I have been looking at some other 45 designs (for the sake of learning) and stumbled across the Bugle 45 (which is probably well known to others)
http://www.wavelengthaudio.com/bugle.pdf
Anyhow, he uses a 700-720 CT power transformer with choke loaded input but a very small cap in the front, 0.68uf.
The specific part about the power supply is the last paragraph on the second page.
Putting 760V with C4=0.68 and C5=220u, constant load of 100mA in PSUD puts B+ at 315V so probably worth a try.
You probably also want a beefy choke in this case (based on what I've read, not personal experience).
One additional option with C4=2.2-4.7u is to add an additional RC stage with a resistance value that will bring down B+ to where you want it
http://www.wavelengthaudio.com/bugle.pdf
Anyhow, he uses a 700-720 CT power transformer with choke loaded input but a very small cap in the front, 0.68uf.
The specific part about the power supply is the last paragraph on the second page.
Putting 760V with C4=0.68 and C5=220u, constant load of 100mA in PSUD puts B+ at 315V so probably worth a try.
You probably also want a beefy choke in this case (based on what I've read, not personal experience).
One additional option with C4=2.2-4.7u is to add an additional RC stage with a resistance value that will bring down B+ to where you want it
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Hello Guys, I have XPWR124 by Edcor, anybody interested let me know. Only used 5 hours or less during testing. Like new condition. I am ready to dispose this.
XPWR124
Primary (input) Voltage 120Vrms, 60Hz. or 240Vrms, 50/60Hz.
Secondary (output) Voltage 640V(320-0-320)@150mA, 6.3V(3.15-0-3.15)@4A & 5V@2A
Bobbin Material Nylon 6/6 GF-30
Flamability Rating Class B 130°C
Core Material M-6 29 ga. grain oriented lamination steel
Secondary Insulation (transformer) Clear air dry polyester varnish
Termination UL1015, 18 ga. lead wire
Mounting Powder coated steel end bells
Color RAL 5010 Gentian Blue
Weight 6 lbs.
Compliance RoHS & REACH
XPWR124
Primary (input) Voltage 120Vrms, 60Hz. or 240Vrms, 50/60Hz.
Secondary (output) Voltage 640V(320-0-320)@150mA, 6.3V(3.15-0-3.15)@4A & 5V@2A
Bobbin Material Nylon 6/6 GF-30
Flamability Rating Class B 130°C
Core Material M-6 29 ga. grain oriented lamination steel
Secondary Insulation (transformer) Clear air dry polyester varnish
Termination UL1015, 18 ga. lead wire
Mounting Powder coated steel end bells
Color RAL 5010 Gentian Blue
Weight 6 lbs.
Compliance RoHS & REACH
Gavin, Yes, I have at least a year's supply of boards and USD $55 is correct for international shipment.
As I have stated before, do not use the "send money to family or friends" option. It does save me some money in Paypal fees, but does NOT allow for printing postage or even forward me your address. Paypal's postage is cheaper than the USPS even with the Paypal fee, and it still goes through the USPS system.
As I have stated before, do not use the "send money to family or friends" option. It does save me some money in Paypal fees, but does NOT allow for printing postage or even forward me your address. Paypal's postage is cheaper than the USPS even with the Paypal fee, and it still goes through the USPS system.
I used an online tool to convert it. It's mostly correct, although some columns have the same value 2 or 3 times. It should take 5-10 mins to trim the excess values. (I don't seem to have an unedited copy after I fixed those)