F5 power amplifier

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
 
woodturner-fran said:
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

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.
 
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
 
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:bigeyes:
 
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
 
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.
 
Formerly "jh6you". R.I.P.
Joined 2006
ashaw,

I could say that both have Vbe(on) of about +0.6 and -0.6V.
Refer to the attached data sheet of FZT692B. So, you could use them as good substitutions without adjustment any.


>:)<
 

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