I can tell you from listening to ATM 1,2 and 4 that airtight are excellent sounding amps. And from having done a small repair to an ATM2 they are very nicely built with very nice transformers. The only quibble I have are those damned alps blue pots for volume control. Thought something better could have gone in there.
More in a couple of days.
Fran
More in a couple of days.
Fran
woodturner-fran said:
Most commercial products have a pricepoint before they design them and they put in what they think sounds good for the price-range. It's not "money is no object" like we can do when we build them ourselves. I've read about people modifying BAT tube amps and other brands to replace parts which they thought were a weak link in an otherwise good product.
mmm price point here for a new atm2 is in the 12k range I believe (although maybe I am wrong). Something better than a veiled 12euro pot could have been employed I thought.
Amp still sounds great though.
Fran
Amp still sounds great though.
Fran
From looking at the inside of it, I would reckon about 1-2k for parts chassis etc etc. Then add labour and so on. FWIW, transformers are tamradio, resistors are a mix of riken, mills and vishay (I think), PS caps are fairly standard looking electros and audio caps are unnamed PP types - round and oval yellow wrapped types. Very nice but simple chassis, very nicely built with a really good feel to it. Make no mistake it is a very good amp.
The only reason I'm holding back on comments between the 2 is that I want to go to my firends listen in a different environment with different components and his speakers are high quality marten design ones that are more full range than mine (quad 57s).
Fran
The only reason I'm holding back on comments between the 2 is that I want to go to my firends listen in a different environment with different components and his speakers are high quality marten design ones that are more full range than mine (quad 57s).
Fran
hi all
im sitting here waiting for my f5 boards and components and have a few questions im hoping someone can answer about my configuration
here goes
ive got 8x f5 boards on the way and am going to build 2 x stereo bridged/balanced amps with them
1) will i loose any sound quality running these amps bridged
2) will the amps in bridged mode be ok with a 4 ohm load
eg,2x ss 25w/8565-01 per cab for bass crossed to 1x manger per cab at 300hz sensitivity is around 88 to 90 db
3) if i use a fan for added cooling will the conrad 350x151 sinks be able to support 2 boards per sink so 4x mosfets each
4) sorry for all the newby questions im a pass labs virgin
im sitting here waiting for my f5 boards and components and have a few questions im hoping someone can answer about my configuration
here goes
ive got 8x f5 boards on the way and am going to build 2 x stereo bridged/balanced amps with them
1) will i loose any sound quality running these amps bridged
2) will the amps in bridged mode be ok with a 4 ohm load
eg,2x ss 25w/8565-01 per cab for bass crossed to 1x manger per cab at 300hz sensitivity is around 88 to 90 db
3) if i use a fan for added cooling will the conrad 350x151 sinks be able to support 2 boards per sink so 4x mosfets each
4) sorry for all the newby questions im a pass labs virgin
if you are a newbie, then build a single F5 and listen to it.
After you have amassed the necessary skills, then think about bridging and other appropriate modifications.
Keep it simple and get it working.
After you have amassed the necessary skills, then think about bridging and other appropriate modifications.
Keep it simple and get it working.
hi andrew
i wish i could but my system is ran through a dbx260 and is active so needs balanced inputs which is why im building a bridged pair of amps
i,ve also built so far a couple of ska gb300 mono blocks ,aussie amps nx400,nvx 200 and ska pre and some hypex 400hg mono,s
so i guess im not a total newby with amps in general just the pass ones
i know a normal f5 will be enough for the mangers but ive got doubghts about it running the bass drivers in my system
believe me id love nothing more than a single f5 driving my whole setup but it just wont work with the 2x scan 25w/8565 in paralell per cab id say they will be too tough a load for a 25w amp to handle
that said id love to be wrong and switch back to passive crossovers and biamp with 2x standard f5 if its possible and would work
regards sheafer
i wish i could but my system is ran through a dbx260 and is active so needs balanced inputs which is why im building a bridged pair of amps
i,ve also built so far a couple of ska gb300 mono blocks ,aussie amps nx400,nvx 200 and ska pre and some hypex 400hg mono,s
so i guess im not a total newby with amps in general just the pass ones
i know a normal f5 will be enough for the mangers but ive got doubghts about it running the bass drivers in my system
believe me id love nothing more than a single f5 driving my whole setup but it just wont work with the 2x scan 25w/8565 in paralell per cab id say they will be too tough a load for a 25w amp to handle
that said id love to be wrong and switch back to passive crossovers and biamp with 2x standard f5 if its possible and would work
regards sheafer
samaloko:
Theres no problem with the 0.51R bit (just adjust the bias voltage to take account of the resistance change) but I'm not sure about the 2W vs 3W rating. I suppose if you have them lying around, you can try it?
My 3W ones get to a surface temp of about 60-65degC
Fran
Theres no problem with the 0.51R bit (just adjust the bias voltage to take account of the resistance change) but I'm not sure about the 2W vs 3W rating. I suppose if you have them lying around, you can try it?
My 3W ones get to a surface temp of about 60-65degC
Fran
Hi SLR,
running a bridged pair of F5 into 4r0 is the same as using a pair of single F5 to drive 2r0.
The ClassA power of an F5 is limited by the ClassA bias current.
I begin to wonder why you want to use a rather nice ClassA amplifier to drive bass only speakers, when for much of the time the amps will be running in ClassAB.
Is your decision to use F5 for the bass valid? Or more a view through rose tinted specs?
There are other ways to use your balanced signal to drive your speakers.
running a bridged pair of F5 into 4r0 is the same as using a pair of single F5 to drive 2r0.
The ClassA power of an F5 is limited by the ClassA bias current.
I begin to wonder why you want to use a rather nice ClassA amplifier to drive bass only speakers, when for much of the time the amps will be running in ClassAB.
Is your decision to use F5 for the bass valid? Or more a view through rose tinted specs?
There are other ways to use your balanced signal to drive your speakers.
ashaw said:
You don't need to change anything as long as the NPN substitution has the base-emitter on voltage of about+0.6V while the PNP of about -0.6V.
If the base-emitter on voltages are quite different from the value of 0.6, you need to adjust the size of R19 and R20.
>🙂<
yes the PNP part FZT792A has a
VBE(on) of -0.75 V at IC=-1A, VCE=-2V
the NPN part FZT692B has a
VBE(on) 0.9 V IC=1A, VCE=2V
VBE(on) of -0.75 V at IC=-1A, VCE=-2V
the NPN part FZT692B has a
VBE(on) 0.9 V IC=1A, VCE=2V
cool they are the only smt parts I thought might be similar enough.
I was thinking of making up some test boards to send to someone with these parts, to compare them to the original if anyone would be interested.
I was thinking of making up some test boards to send to someone with these parts, to compare them to the original if anyone would be interested.
comparisons should be done using as close as possible the range of operating currents expected in the completed amplifiers.ashaw said:
1A @ 2Vce is preposterous.