mcfrede skrev:Hi Frans,
Thank you for taking the time to help me out. It is greatly appreciated.
I think we should be looking at sub-50$ kits so I searched eBay for (a few) more alternatives:
#1: OPA2604 Servo Preamplifier @ 23$
Looks very simple, perhaps too simple since I guess people will want to do a little more soldering than these few components. Might encourage OpAmp rolling as you said.
#2: LJM- HA-PRO2 Headphone amplifier @ 33$
Looks as simple as #1, but features 4 opamps, I lack the insight to determine which is best (although this one DOES state it is "professional version).
#3: E3 Headphone amplifier with UPC1237 protection @ 42$
Dual OpAmp design with protection.
#4: Headphone Amplifier Base on Lehmann AMP Circuit @30$
This is the one we discussed yesterday.
These are within the price range, but requires the builder to trim it, so maybe they should be discarded for "beginners class"?
#5: E4 FET headphone Class A Amplifier with UPC1237 Protection @ 37$
Looks like the FET version of the E3 above.
#6: OPA627+2SA1930 2SC5171 headphone amplifier @ 40$
Discarded due to price above 50$, should only be considered if likely to give Panda-like "value for money"
#7: HV1 Headphone amplifier @ 57$
#8: HV2 Headphone amplifier (base on HA2002 HA5000) @ 71$
#9: HV4 Headphone amplifier @ 52$
...
Solderdude skrev:1 = glorified C'Moy
2 = glorified C'moy with protection circuit
3 = as 4 but with protection, cheap volpot
4 = standard amp design, no protection reasonable volpot
5 = similar to Panda, needs adjusting
6 = as 3 but needs adjustment, cheap pot
7 = as 3 with protection and good pot, gimmick input caps
8 = Panda alike, poor volpot, needs adjustment, gimmick input caps
9 = as 7 but needs adjustment.
to me reasonable options: 2, 3 but install better, 4 volpot, 7, 9 for beginners.
mcfrede skrev:Hvad siger i andre (og er der stadig folk der kunne være interesserede)?
Postkurt skrev:mcfrede skrev:Hvad siger i andre (og er der stadig folk der kunne være interesserede)?
Jeg er fortsat interesseret i et lille projekt.
Mit mål er, ud over at få mig en lille forstærker, med tiden, at kunne lave en af Frans' "Project Sunrise MK II ".
Mit niveau mht. DIY er begrænset til lidt kabelsnedkeri. Er det mon en tilstrækkelig baggrund til at deltage i dette projekt?
Hvor meget ligger der i "justering efter endt lodning"?
Kolind skrev:Postkurt skrev:mcfrede skrev:Hvad siger i andre (og er der stadig folk der kunne være interesserede)?
Jeg er fortsat interesseret i et lille projekt.
Mit mål er, ud over at få mig en lille forstærker, med tiden, at kunne lave en af Frans' "Project Sunrise MK II ".
Mit niveau mht. DIY er begrænset til lidt kabelsnedkeri. Er det mon en tilstrækkelig baggrund til at deltage i dette projekt?
Hvor meget ligger der i "justering efter endt lodning"?
På pandaen handlede det om at måle imellem to punkter og dreje på to potmetre med en skruetrækker indtil den ramte det rigtige niveau. Let nok, udover at det lidt krævede tre fire hænder eller ret god snilde..
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