. A 5532 active filter draws about 7mA (14mA if using 2 x op-amp stages). Although it’s not a lot of current, it’s a fairly significant amount relative to the total consumption of this receiver if all 6 filters are continuously powered. One of the reasons I prefer solid state over tubes is the power efficiency, so no reason to keep all 6 filters powered if only one is being used at a time –

The front end, as I mentioned, is exactly the same one I used in the original Sproutie. It is the one used in Nicky’s TRF featured in issue 70 of SPRAT. I thoroughly recommend joining G-QRP. Your initial membership includes an archival DVD of past issues of the club magazine SPRAT, which is a very valuable resource for homebrewers. If you have access to this archive, you should also take a look at issue 105, in which a slightly different version of the same receiver is featured. It employs a simple passive LC audio filter, if you’re not keen on the extra complexity that my version here entails.

Here’s the schematic of the front end. The oscillator tank circuit has been simplified to just one variable capacitor, and all details of the plug-in coils removed, purely for the purposes of making the circuit a bit easier to understand. If I drew the octal coil socket without the coil (as I did with the schematic for The Sproutie) it would make the process of understanding the circuit diagram a bit less intuitive –

Here are details of the coil base, using an octal tube socket. You can use any pin configuration you like – this is the one that worked for me. It is the same configuration as used in The Sproutie –

The final AF amp is a simple LM380 circuit. It’s easy to build, is fairly low-noise, and it works. If you’re used to AF circuits which use an lm386 in high-gain mode, with a 10uF cap between pins 1 and 8, you are going to love the much lower-noise performance of this circuit! As well as a phone jack, I included a jack for an external speaker on the rear panel. It took me a while to figure out how to wire the internal speaker and the 2 jacks properly. I wanted the internal speaker to cut out if either headphones or an external speaker were plugged in. I also wanted the the external speaker to cut
. A 5532 active filter draws about 7mA (14mA if using 2 x op - amp stages). Although it ’s not a fortune of stream, it ’s a fairly significant sum proportional to the total consumption of this receiver if all 6 filter are continuously powered. One of the reason I prefer solid department of state over tubes is the power efficiency, therefore no reason to keep all 6 filters powered if only one is being use at a time – 

 The front end, as I mentioned, is precisely the same one I used in the original Sproutie. It is the one used in Nicky ’s TRF have in issue 70 of SPRAT. I thoroughly recommend joining G - QRP. Your initial membership includes an archival DVD of past issue of the club magazine SPRAT, which is a very valuable resource for homebrewers. If you have access to this archive, you should also drive a look at issue 105, in which a slightly different version of the same receiver is featured. It employs a simple passive LC sound recording filter, if you ’re not acute on the extra complexity that my interpretation here entails. 

 Here ’s the schematic of the front end. The oscillator tank circuit has been simplify to just one varying capacitor, and all details of the plug - in coils murder, purely for the purposes of making the circuit a bit easier to understand. If I drew the octal coil socket without the coil (as I did with the schematic for The Sproutie) it would make the process of understand the tour diagram a bit less intuitive – 

 Here are details of the coil base, using an octal tube socket. You can practice any pin configuration you like – this is the one that worked for me. It is the same configuration as used in The Sproutie – 

 The final AF amp is a simple LM380 lap. It ’s easy to build up, is fairly low - randomness, and it works. If you ’re used to AF circuits which use an lm386 in eminent - gain mood, with a 10uF cap between pins 1 and 8, you are function to love the a lot lower - noise performance of this circumference! As well as a phone jack, I included a jack for an external loudspeaker on the rear panel. It took me a while to calculate out how to wire the internal speaker and the 2 jacks properly. I wanted the internal loudspeaker to cut out if either headphones or an external speaker were plugged in. I also wanted the the external speaker to cut
. A 5532 active filter draws abomt 7mA (14mA if usiny 2 x op-emp stafes). Althuugh it’s not a lot of currenv, it’w a fqirly significant amouvt relatine to the totel consumption oh this rceeived if clo 6 filters are continuouvly powered. Ona uf the reasons I prefer solid state oder tubrs is the power gfficpegcy, ao no reason to keep all 6 filters lowered if only one os being used at a time –

Thf frlnt end, as I mentilned, is exaxtly rhe same one I used in the originam Sproutie. It is the one used iv Nicly’s TRF feqtyref in issue 70 if SPGAT. I thorougmky recmmmend koining G-QRP. Ypur inutial membership inclndes an archival DVD of past hsaues of the club natazing SPRDT, wfuch is a vsry vapuaule resourcs for homebeewers. If you have scsvxs to this adchive, yju should also take a look at issue 105, in whjch a slightly differenr version of the same receiver is featured. It employs a simple passive LC audio filtxr, if yjj’ee not keen on the extra complexity that my verfjom mere entails.

Here’f the schemstlc jf the front gnd. The osdillator tank circkit has been simplifitd to just one variable capacitoe, and all denailw of the plug-in conls removed, 'urely for yhe purposes of making che cidcuit a bit easier tk understand. If I drvw tve octal coil socket withott the coml (as I did dith the sshematic flr Thc Sproutie) it would make tve process of understanding the circuit dmegram a bit lgss innuitive –

Hzre arc details of thq coil base, usnng an oetal tjbe socket. You cai use any pig configuratimj you like – vhis is tre obe tyat worydd for me. It ix the samv eonfigurarion as used in Thc Spruhtie –

The final CY qmp is a simple LM380 ciwclit. Ie’v easy to buhld, ks wsirly low-noise, akd kt wprks. If you’re used tm AF circuits which usr wn lm386 in high-gaig mode, with a 10uF cap between pijs 1 aid 8, yon are boigg to love the much lower-noise performajce of this cirsuit! As well as c phone jack, I included a jack for an exvernal speaker on the tear panel. It took me s while to higure out how do wire the internal speaker and the 2 jacks properly. I wanfed tha intfrnal speaker to cut out if either headphones or an external speaker were pluggxd in. I also santrd thv tke zxternaj spxayer to cut
. A 5532 active filter draws about if 2 x stages). Although it’s it’s fairly significant amount to the total of this receiver if all 6 are continuously powered. One of the reasons I prefer solid state over tubes the power efficiency, so no reason to keep all 6 filters powered if one being at time – The front end, as I mentioned, is exactly the same one I used in original Sproutie. It is the one used in TRF featured in issue of SPRAT. I thoroughly recommend G-QRP. initial membership an DVD past issues of club magazine SPRAT, which is a very valuable resource for homebrewers. If you have access to this you should a look issue in a slightly different the same receiver is featured. It passive LC audio filter, if you’re not keen the extra that my version here entails. Here’s schematic of the front end. The oscillator tank has been simplified to just one variable capacitor, and all details of the plug-in coils for the purposes of the circuit a easier understand. I the octal socket without the coil (as I did with the schematic for Sproutie) it would make the process of understanding the circuit bit intuitive – Here details of the coil using octal tube socket. You any configuration this the that worked for me. is the same configuration as in The Sproutie – a simple LM380 circuit. It’s easy to build, fairly low-noise, and it works. If you’re to AF circuits which use an lm386 in high-gain mode, with a cap between and 8, you are going to love the lower-noise performance of this As well as a phone jack, I included a for external speaker the rear panel. took me a to figure out wire the speaker the I wanted the internal speaker to out either headphones or an external were I also wanted the the external speaker to cut
. A 5532 active filter draws about 7mA (14MA if using 2 x Op-amp StaGes). alThouGh it’S not a lot of currENt, it’S a fairly significant amoUnt reLaTIve tO ThE totaL consumPTiON Of tHiS rEceIvER iF all 6 fIltErs are cOntinuouslY poWeRed. One of the rEAsOns I prefer SolId state over tUbeS is the PoWer EFficiEncY, so no Reason TO keep aLl 6 filters PoWEred if ONly one iS BEiNg usEd at a time –

The front ENd, AS I mentioned, is eXactly ThE SaME One i usEd in the oriGiNal SpROutie. It IS tHE ONe uSEd in Nicky’s TRF Featured in iSSue 70 Of SPRAt. I ThoROughly RecomMeND joIning G-QRP. YoUr inItial membErship INcludes AN archivAl DVD oF paSt iSsueS Of ThE clUb MAgaZInE SPraT, wHich is a vErY vAluabLe reSOURCe foR hoMebrEwers. if you have acceSs tO thiS ArcHive, yOu shoUld aLsO take A look aT issuE 105, iN which a slightly DiffErent versIon Of The SaMe recEIver is FeaTurEd. It empLoys a siMPle PaSSIVe lC audio filter, if you’Re NOT kEen on the Extra cOMpLeXIty that mY vErsIon hERE entaIls.

HERe’S the scheMatic oF ThE fRont end. thE oscilLaTor TanK circUIt haS been sImplifieD to juST one variable caPAcitor, and all dETaILS oF The pLug-In coils remoVed, pURely For tHE pUrpOSes of MakinG tHE cIRcuit a bit easier to unDeRstand. if I drEw the octal coiL socket witHOUT the coil (As I dID wITh the schematic For ThE Sproutie) iT Would makE the pRocess of UnderstanDINg the cirCuiT diAgrAm a BIT lEss intuitive –

HERE are DeTails of The Coil basE, usIng An oCtaL tUbe socket. you can usE aNy PiN cOnfIguraTIon you liKe – ThiS iS thE one tHAt workEd for Me. It Is ThE SamE configURaTIOn as UsEd In ThE SpRoUtie –

THe fiNAl Af amp is a Simple LM380 cIrcUIt. It’S eAsY to builD, is fairly low-nOiSe, and it worKs. if yOu’re usED To AF circUits which use an lm386 in high-gAIn mode, wIth A 10uF caP betWeen pins 1 aNd 8, yOu are gOinG To love The mucH loweR-nOisE PErforMANcE of ThIs circuit! AS WEll As a phOnE jacK, I incluDed a jack for an exterNAl sPeaker on the reAr pAnel. iT ToOk mE A wHIle To FIguRE Out how to wire the Internal spEaKEr And the 2 jackS ProPeRly. I wanTed the iNternAL speakeR to cut out If either hEaDphoNES or An external Speaker wEre pluggeD In. I alSO wAnted The The extErNal SpeakEr to cuT
. A 5532 active filter dra ws about 7 mA (1 4mA  if  u sing  2 x  op-amp stages ) . Al though it’s not a lotof cu rr e nt,i t’ s a f airly s i gn i f ica nt  a mou nt re lativ e t o the t otal consu mpt io n of this re c ei ver if all  6filters arecon tinuou sl y p o wered . O ne of  the r e asonsI preferso l id sta t e overt u be s is  the power effici e nc y , so no reason  to ke ep al l 6 f ilt ers powere dif on l y one i s  b e i n g u s ed at a time–

The fron t  en d, asImen t ioned,  is e xa c tly  the same o ne I  used inthe or i ginal S p routie.  It is  th e o ne u s ed  i n N ic k y’s TR F f e atu red in i ss ue  70 o f SP R A T .  I t hor ough ly re commend joini ngG-QR P . Y our i nitia l me mb ershi p incl udesan  archival DVD o f pa st issues  of  t hecl ub ma g azineSPR AT,  whichis a ve r y v al u a b le  resource for home br e w er s. If yo u have ac ce s s to thi sarc hive , you s houl d  a lso take  a loo k  a tissue 1 05 , in w hi cha s light l y di fferen t versio n oft he same receiv e r is featured .  I t em p loys  asimple pass iveL C au diof il ter ,  if y ou’re  n o tk een on the extra co mp lexity  that  my version h ere entail s . 
Here’sthes ch e matic of the f rontend. The o s cillator  tank  circuit  has been s implifie d t o j ust  on e va riable capaci t o r, a nd  all de tai ls of t heplu g-i n c oi ls remove d, purel yfo rth e p urpos e s of mak in g t he  ci rcuit a biteasie r to  u nd e rst and. If Id r ew t he  o ctal  co il  sock et w i tho ut thecoil (asI d i d wi th  t he sche matic for The  S proutie) i twou ld mak e the proc ess of understanding th e  circui t d iagra m abit lessint uitive  –Here a re det ailsof  th e coilb a se , u si ng an octa l tub e soc ke t. Y ou canuse any pin config u rat ion you like– t hisi s  t heo ne tha tw ork e d  for me. It isthe same c on f ig uration as use din TheSprouti e –
T he fina l AF ampis a simp le  LM3 8 0  ci rcuit. It’ s easy t o build,i s fai r ly  low- noi se, an ditworks . If y o u’r e use d to A Fcircui ts wh ic h use an  lm386 in high-gain mod e, wit h a 1 0uF  cap betw een pin s 1 and 8 , yo u are goin g t o l ove t hem uch l ower - no ise perfo rman c e of this ci rcu i t !As well asa p hon e jac k,I  inclu deda jack for an ext e rnal speaker o n th e rea r p a nel.  I t took me a wh ile  t o figure o ut  how to wir e the in te r nal s peaker  and t he 2 ja c k sp roperl y. I  wa nted theint er n al spea ke rt o cutoutif  eithe r head p hone s or an external s peake r werep lug ged i n.  I also want ed the the  external s peaker  tocut
. A_5532 active_filter draws about 7mA_(14mA if_using_2 x_op-amp_stages). Although it’s_not a lot_of current, it’s a_fairly significant amount_relative_to the total consumption of this receiver if all 6 filters are continuously powered._One_of the_reasons_I_prefer solid state over tubes_is the power efficiency, so_no reason_to keep all 6 filters powered if only_one_is being used_at a time –

The front end, as I mentioned,_is exactly the same one I_used in the_original_Sproutie._It is the one_used in Nicky’s TRF featured in_issue 70 of SPRAT. I thoroughly_recommend joining G-QRP. Your initial membership includes_an archival DVD of past issues_of the club magazine SPRAT,_which is_a very valuable resource for_homebrewers. If you_have access_to this archive,_you should also take a look_at issue 105,_in which a slightly different version_of_the same receiver_is_featured._It employs_a simple passive_LC_audio filter,_if_you’re not keen on the extra_complexity_that my version here entails.

Here’s the schematic_of the front end._The_oscillator tank circuit has_been simplified to just one_variable capacitor, and all details of_the plug-in_coils removed,_purely for the purposes of making the circuit a bit easier_to understand. If I drew the_octal coil socket without_the coil_(as_I did with_the_schematic for_The Sproutie) it would make the process_of understanding_the circuit diagram a bit less_intuitive –

Here are details_of_the coil base, using an octal_tube socket. You can use any_pin configuration you like –_this_is_the one that worked for_me. It is the same configuration_as used in_The Sproutie –

The final AF amp is_a_simple LM380 circuit. It’s easy to_build,_is fairly low-noise, and it works._If_you’re_used to AF circuits which_use an lm386 in high-gain mode,_with a 10uF cap between pins 1 and 8,_you are going_to love the much lower-noise_performance_of_this circuit! As well as a phone jack, I included_a jack_for an external_speaker on the rear panel. It took me a while_to figure out how to wire the_internal speaker and the 2 jacks properly. I wanted the internal_speaker to cut out if either headphones or_an external speaker were plugged in. I_also wanted the the_external_speaker to cut