Thanks Bicolor - it will be really useful to know how it sounds with rock into that speaker - I know the Mission 7xx range too! The seller (cn_china) is asking $160 postage which is huge for such a light amp, so I need to know it's worth buying before I stump up that amount!
Your flat-panel speaker array looks superb BTW but I have a question: How are the bass units wired up?
Thanks in advance,
Graham
Globulator -> I got mine from hllyaudio.com, 308$ or 215 Euro, including shipping.
It took two weeks from paying it until it arrived on my doorstep.
Sorry I have not had the time to do any serious listening, difficult with two small children running around all day long.
They are never quiet, I assure you!
It took two weeks from paying it until it arrived on my doorstep.
Sorry I have not had the time to do any serious listening, difficult with two small children running around all day long.
They are never quiet, I assure you!
After about a week of listening I feel it is worth replacing the coupling caps(vishay roederstein MKP), series grid stoppers (used Vishay Beyschlag) and swapping the 6n1p for the 6n6p ( performs better with stock plate/anode resistors & B+). Probably not going to change much else with the Peach for a while, the bit of grit and unrefinement that was bugging me before is gone and the amp is now an absolute pleasure to listen to.
I'm a little new to tube design - could you post of the definitive Peach schematic of your amp? What values did you use for the coupling caps and the stopper resistors? Can the 6n6p just plug straight in?
Oh a BTW I caved in to hllyaudio's superior pricing and bought a FU50 Peach which should be here in a couple of weeks I hope
. I have an Usher R1.5 it has to compete with...So I'll be ordering the upgrades in the meantime and when it arrives I'll commission it on the Variac and check the voltages (My village is usually 250V) to see if a need a buck transformer. Do you all fit new rectifier diodes and soft start thermistors? What value and type of bleeder resistors?
Thanks in advance!
Good news!
I will also replace the 0,1uF coupling caps, I do not trust them since there are chinese copies of the Wima caps out there, and the quality is a real questionmark.
I will also change the plate resistors in mine, since they differ too much, over 1k!
However I will stick to the original (3k) gridstoppers, maybe change them later since I already have a whole shoppingbag of beyshlag reisistors.
I have listened quite a lot to my peach, though not being home alone, so really listening to details have been almost impossible.
Sadly I am not completely pleased with the sound. Yet.
Please do not complain, here are some of my impressions of the sound so far.
With the 6n1p the bass feels tight and powerful, you might say "physical". The midrange... well...I cant put my finger on it but clearly there is something bothering me, sometimes I think it's quite good, sometimes quite poor. Unrefined, unlinear, Un-something. Highs are crisp and good.
The 6n23p makes the amp "calm down" somewhat, like driving a 300hp car at half throttle compared to the 6n1p.
Overall it feels like a smoother presentation, but also more boring.
Bass is there but not as defined and prominent, mids are smooth, but I cant get a grip of it, there is something lacking. Highs are also smoother.
I like the "slam" and "speed" I get with the 6n1p.
Maybe the 6n6p in combination with new coupling caps will do the trick and give me the magical mids I am missing.
Or swapping in some other plate and cathode resistors and sticking to the 6n1p to make it work more linear may be the way to go for me. I do not know.
Any suggestions are welcome.
I am not saying it sounds bad, remember I am comparing to other more expensive tube amps. In some ways it is not at all far behind the 300B amps I've owned (speed) and in others it is nowhere close (mostly midrange).
Audioromy makes a lot of crap, but their 838A model with FU13 power tubes is ok, I have also seen some people praising the GU29 model. I have used the Audioromy FU13 for one and a half year now to power my Magnepan SMGa´s, Its given no trouble. It came in the same crappy packaging pictured early in this string. I bought it from On9mart.com through their ebay sales. There is a strong interest in it in Germany. Here in Norway The Music Angel KT88 push-pull is pretty popular
Oh, and Globulator, all the tech talk about 0,1uF coupling caps, 47k plate resistors, 3k gridstoppers confused me too, until I got the amp home and opened it up and measured the values of the resistors and saw the layout of the board. All those parts are on the same circuitboard. You do not accept PM:s, but if you can send me a PM or email you are welcome to do so.
I am a tube noob in the sense that I have never done more than change tubes in my amps until now.
I am a tube noob in the sense that I have never done more than change tubes in my amps until now.
Hi Bicolor!
I have enabled PMs now, I didn't realise they were off - please feel free! Bit of a tube learning curve (along with the 'interesting' safety thread!) for me, the last tube amp I used in earnest was a lovely Armstrong 8W push-pull EL84 back in the 1970's when they were all over the place!! It was just a chassis too, never got a shock from it though, all those came from solid state - ironic.
I have a reasonable knowledge of solid state electronics but references like sand (silicon), SUT (step up transformer for MC phono), plate, stopper, CCS, SRRP etc are all new, I've been using Google a lot!
I have a feeling that the Peachy can sound very very good but needs one or two tweaks to get there, the 6n6p change (is this a straight plug-in mod?) seems interesting along with the other mods mentioned.
I'll be ripping out the phono stage too, as I have an external one (awaiting VAT payment at the post office). As for the DAC input, if they think I'm plugging my PC into anything with those kind of voltages the're wrong!!
The aim is to make it sound as good as the Audioromy FU13 I could not afford does
.I consider the 6n6p a potential "cure" for this particular application of the 6n1p, in the stock Peach the 6n1p operates at the the very lower limits of its curves with a very shallow load line, I suppose in theory this would allow the 6n1p to swing the greatest voltage but at a cost in sound quality. You can either change your plate resistor to something closer to 27k along with the cathode to about 325 ohms or swap in a tube that doesn't mind the stock 47k/1k combo such as the 6n6p (if you take a look at it's datasheet it appears to be very easy to work with and VERY powerful). So yes it is a drop in.
Bicolor, I think the 6n6p will improve the midrange to your liking as it isn't as gritty and unrefined as the 6n1p in this circuit..or better yet if you have some 3-5watt resistors change the plate and cathode resistors for the 6n1p, I just don't seem to have the time to play with this amp as much, I have a hotrod Volvo I'm working on these days.
Bicolor, I think the 6n6p will improve the midrange to your liking as it isn't as gritty and unrefined as the 6n1p in this circuit..or better yet if you have some 3-5watt resistors change the plate and cathode resistors for the 6n1p, I just don't seem to have the time to play with this amp as much, I have a hotrod Volvo I'm working on these days.
Hotrod Volvo? Are you serious? Which model is it based on?
"PV" 544? "Amazon" 122? 140-series?
I have a '61 Amazon P120, completely original..
I have finally gotten some time all alone at home, and took 1-2 hours to do some serious listening. I am starting to change my opinion here, playing with the 6n1p it has great tight bass and the highs are...maybe a bit too harsh for my ears.
Mids are there but far from ideal. Some instruments sound a bit dull, with no clear "edges".
I quickly swapped to the 6n23p and the sound is now much better balanced. Objectively, the bass gets a bit softer but it is still there, mids are actually much better (probably because the highs and lows are more linear??) and the higs feel more airy, simply sounds better.
I have ordered some mkp caps and 6n6p tubes from the 60's, I'll give a report when they are in place.
Still haven't decided if I am going to try other grid and cathode resistors, it would be fun to see how the 6n1p would sound given a better operating point.
Guess I'll follow your lead first, changing the caps and try the 6n6p.
I feel like I can now live with it as it is. Though tweaking it further is tempting.
"PV" 544? "Amazon" 122? 140-series?
I have a '61 Amazon P120, completely original..
I have finally gotten some time all alone at home, and took 1-2 hours to do some serious listening. I am starting to change my opinion here, playing with the 6n1p it has great tight bass and the highs are...maybe a bit too harsh for my ears.
Mids are there but far from ideal. Some instruments sound a bit dull, with no clear "edges".
I quickly swapped to the 6n23p and the sound is now much better balanced. Objectively, the bass gets a bit softer but it is still there, mids are actually much better (probably because the highs and lows are more linear??) and the higs feel more airy, simply sounds better.
I have ordered some mkp caps and 6n6p tubes from the 60's, I'll give a report when they are in place.
Still haven't decided if I am going to try other grid and cathode resistors, it would be fun to see how the 6n1p would sound given a better operating point.
Guess I'll follow your lead first, changing the caps and try the 6n6p.
I feel like I can now live with it as it is. Though tweaking it further is tempting.
Thats cool, a friend of mine up the road has a restored 120 he painted a nice Aston Martin green metalic. I just bought a Volvo 780 Bertone coupe, its being restored to stock status (down to the radio) with the exception of the drive train which has over 300k miles so its making way for a Ford 5.0l v8 and 5spd tranny. When I was a Volvo salesman I drove a 1980 245 wagon with a 5.0 and T5 5spd and it was a blast!
got my .1uf caps today, swapping the wima:s was an easy job that did not take many minutes. I am not a professional but I do know how to solder. Have not had the time to listen to it more than to check that it still works.
I also ordered 3w 27k resistors, dont have any close to 325 ohms over 0,25-0,5w, if I remember correctly the stock 1k resistors were also small suggesting I may be fine with the ones I have. I will check which resistors I have at home.
I think I will relax for a few days, I am expecting four 6n6p tubes to arrive by the end of the week, wont change anything else right now.
I also ordered 3w 27k resistors, dont have any close to 325 ohms over 0,25-0,5w, if I remember correctly the stock 1k resistors were also small suggesting I may be fine with the ones I have. I will check which resistors I have at home.
I think I will relax for a few days, I am expecting four 6n6p tubes to arrive by the end of the week, wont change anything else right now.
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If the Sweet Peach schematic is correct the original 6N1P runs with an anode resistor of 47k dropping (200-128) = 1.53mA.
So the 1k cathode resistor is therefore at 1.53V bias, which is a little low, and could be substituted for a red LED (1.7V) and a smaller resistor for the anode?
However I want to substitute that for an ECC88 which I can run at 2mA if I use a 4V cathode to grid voltage (Two orange leds) with a 36K anode resistor [disclaimer - I'm new to load lines!!]. What do you think?
Attachments
The original circuit uses 47k anode (plate) resistors.
I am using a 6n23p which is equivalent to the ecc88. I have not made any changes as of yet and it sounds pretty good.
Let us know when you get your amp, and how you decide to modify it.
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